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/ *
* linux/ a r c h / i 3 8 6 / e n t r y . S
*
* Copyright ( C ) 1 9 9 1 , 1 9 9 2 L i n u s T o r v a l d s
* /
/ *
* entry. S c o n t a i n s t h e s y s t e m - c a l l a n d f a u l t l o w - l e v e l h a n d l i n g r o u t i n e s .
* This a l s o c o n t a i n s t h e t i m e r - i n t e r r u p t h a n d l e r , a s w e l l a s a l l i n t e r r u p t s
* and f a u l t s t h a t c a n r e s u l t i n a t a s k - s w i t c h .
*
* NOTE : This c o d e h a n d l e s s i g n a l - r e c o g n i t i o n , w h i c h h a p p e n s e v e r y t i m e
* after a t i m e r - i n t e r r u p t a n d a f t e r e a c h s y s t e m c a l l .
*
* I c h a n g e d a l l t h e . a l i g n ' s t o 4 ( 1 6 b y t e a l i g n m e n t ) , a s t h a t ' s f a s t e r
* on a 4 8 6 .
*
* Stack l a y o u t i n ' r e t _ f r o m _ s y s t e m _ c a l l ' :
* ptrace n e e d s t o h a v e a l l r e g s o n t h e s t a c k .
* if t h e o r d e r h e r e i s c h a n g e d , i t n e e d s t o b e
* updated i n f o r k . c : c o p y _ p r o c e s s , s i g n a l . c : d o _ s i g n a l ,
* ptrace. c a n d p t r a c e . h
*
* 0 ( % esp) - % e b x
* 4 ( % esp) - % e c x
* 8 ( % esp) - % e d x
* C( % e s p ) - % e s i
* 1 0 ( % esp) - % e d i
* 1 4 ( % esp) - % e b p
* 1 8 ( % esp) - % e a x
* 1 C( % e s p ) - % d s
* 2 0 ( % esp) - % e s
* 2 4 ( % esp) - o r i g _ e a x
* 2 8 ( % esp) - % e i p
* 2 C( % e s p ) - % c s
* 3 0 ( % esp) - % e f l a g s
* 3 4 ( % esp) - % o l d e s p
* 3 8 ( % esp) - % o l d s s
*
* " current" i s i n r e g i s t e r % e b x d u r i n g a n y s l o w e n t r i e s .
* /
# include < l i n u x / l i n k a g e . h >
# include < a s m / t h r e a d _ i n f o . h >
# include < a s m / e r r n o . h >
# include < a s m / s e g m e n t . h >
# include < a s m / s m p . h >
# include < a s m / p a g e . h >
# include < a s m / d e s c . h >
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# include < a s m / d w a r f2 . h >
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# include " i r q _ v e c t o r s . h "
# define n r _ s y s c a l l s ( ( s y s c a l l _ t a b l e _ s i z e ) / 4 )
EBX = 0 x00
ECX = 0 x04
EDX = 0 x08
ESI = 0 x0 C
EDI = 0 x10
EBP = 0 x14
EAX = 0 x18
DS = 0 x1 C
ES = 0 x20
ORIG_ E A X = 0 x24
EIP = 0 x28
CS = 0 x2 C
EFLAGS = 0 x30
OLDESP = 0 x34
OLDSS = 0 x38
CF_ M A S K = 0 x00 0 0 0 0 0 1
TF_ M A S K = 0 x00 0 0 0 1 0 0
IF_ M A S K = 0 x00 0 0 0 2 0 0
DF_ M A S K = 0 x00 0 0 0 4 0 0
NT_ M A S K = 0 x00 0 0 4 0 0 0
VM_ M A S K = 0 x00 0 2 0 0 0 0
# ifdef C O N F I G _ P R E E M P T
# define p r e e m p t _ s t o p c l i
# else
# define p r e e m p t _ s t o p
# define r e s u m e _ k e r n e l r e s t o r e _ n o c h e c k
# endif
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# ifdef C O N F I G _ V M 8 6
# define r e s u m e _ u s e r s p a c e _ s i g c h e c k _ u s e r s p a c e
# else
# define r e s u m e _ u s e r s p a c e _ s i g r e s u m e _ u s e r s p a c e
# endif
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# define S A V E _ A L L \
cld; \
pushl % e s ; \
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CFI_ A D J U S T _ C F A _ O F F S E T 4 ;\
/*CFI_REL_OFFSET es, 0;*/ \
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pushl % d s ; \
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CFI_ A D J U S T _ C F A _ O F F S E T 4 ;\
/*CFI_REL_OFFSET ds, 0;*/ \
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pushl % e a x ; \
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CFI_ A D J U S T _ C F A _ O F F S E T 4 ;\
CFI_ R E L _ O F F S E T e a x , 0 ;\
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pushl % e b p ; \
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CFI_ A D J U S T _ C F A _ O F F S E T 4 ;\
CFI_ R E L _ O F F S E T e b p , 0 ;\
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pushl % e d i ; \
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CFI_ A D J U S T _ C F A _ O F F S E T 4 ;\
CFI_ R E L _ O F F S E T e d i , 0 ;\
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pushl % e s i ; \
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CFI_ A D J U S T _ C F A _ O F F S E T 4 ;\
CFI_ R E L _ O F F S E T e s i , 0 ;\
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pushl % e d x ; \
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CFI_ A D J U S T _ C F A _ O F F S E T 4 ;\
CFI_ R E L _ O F F S E T e d x , 0 ;\
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pushl % e c x ; \
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CFI_ A D J U S T _ C F A _ O F F S E T 4 ;\
CFI_ R E L _ O F F S E T e c x , 0 ;\
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pushl % e b x ; \
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CFI_ A D J U S T _ C F A _ O F F S E T 4 ;\
CFI_ R E L _ O F F S E T e b x , 0 ;\
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movl $ ( _ _ U S E R _ D S ) , % e d x ; \
movl % e d x , % d s ; \
movl % e d x , % e s ;
# define R E S T O R E _ I N T _ R E G S \
popl % e b x ; \
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CFI_ A D J U S T _ C F A _ O F F S E T - 4 ;\
CFI_ R E S T O R E e b x ;\
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popl % e c x ; \
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CFI_ A D J U S T _ C F A _ O F F S E T - 4 ;\
CFI_ R E S T O R E e c x ;\
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popl % e d x ; \
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CFI_ A D J U S T _ C F A _ O F F S E T - 4 ;\
CFI_ R E S T O R E e d x ;\
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popl % e s i ; \
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CFI_ A D J U S T _ C F A _ O F F S E T - 4 ;\
CFI_ R E S T O R E e s i ;\
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popl % e d i ; \
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CFI_ A D J U S T _ C F A _ O F F S E T - 4 ;\
CFI_ R E S T O R E e d i ;\
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popl % e b p ; \
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CFI_ A D J U S T _ C F A _ O F F S E T - 4 ;\
CFI_ R E S T O R E e b p ;\
popl % e a x ; \
CFI_ A D J U S T _ C F A _ O F F S E T - 4 ;\
CFI_ R E S T O R E e a x
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# define R E S T O R E _ R E G S \
RESTORE_ I N T _ R E G S ; \
1 : popl % d s ; \
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CFI_ A D J U S T _ C F A _ O F F S E T - 4 ;\
/*CFI_RESTORE ds;*/ \
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2 : popl % e s ; \
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CFI_ A D J U S T _ C F A _ O F F S E T - 4 ;\
/*CFI_RESTORE es;*/ \
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.section .fixup , " ax" ; \
3 : movl $ 0 ,( % e s p ) ; \
jmp 1 b ; \
4 : movl $ 0 ,( % e s p ) ; \
jmp 2 b ; \
.previous ; \
.section _ _ ex_ t a b l e ," a " ;\
.align 4 ; \
.long 1 b,3 b ; \
.long 2 b,4 b ; \
.previous
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# define R I N G 0 _ I N T _ F R A M E \
CFI_ S T A R T P R O C s i m p l e ;\
CFI_ D E F _ C F A e s p , 3 * 4 ;\
/*CFI_OFFSET cs, -2*4;*/ \
CFI_ O F F S E T e i p , - 3 * 4
# define R I N G 0 _ E C _ F R A M E \
CFI_ S T A R T P R O C s i m p l e ;\
CFI_ D E F _ C F A e s p , 4 * 4 ;\
/*CFI_OFFSET cs, -2*4;*/ \
CFI_ O F F S E T e i p , - 3 * 4
# define R I N G 0 _ P T R E G S _ F R A M E \
CFI_ S T A R T P R O C s i m p l e ;\
CFI_ D E F _ C F A e s p , O L D E S P - E B X ;\
/*CFI_OFFSET cs, CS-OLDESP;*/ \
CFI_ O F F S E T e i p , E I P - O L D E S P ;\
/*CFI_OFFSET es, ES-OLDESP;*/ \
/*CFI_OFFSET ds, DS-OLDESP;*/ \
CFI_ O F F S E T e a x , E A X - O L D E S P ;\
CFI_ O F F S E T e b p , E B P - O L D E S P ;\
CFI_ O F F S E T e d i , E D I - O L D E S P ;\
CFI_ O F F S E T e s i , E S I - O L D E S P ;\
CFI_ O F F S E T e d x , E D X - O L D E S P ;\
CFI_ O F F S E T e c x , E C X - O L D E S P ;\
CFI_ O F F S E T e b x , E B X - O L D E S P
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ENTRY( r e t _ f r o m _ f o r k )
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CFI_ S T A R T P R O C
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pushl % e a x
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CFI_ A D J U S T _ C F A _ O F F S E T - 4
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call s c h e d u l e _ t a i l
GET_ T H R E A D _ I N F O ( % e b p )
popl % e a x
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CFI_ A D J U S T _ C F A _ O F F S E T - 4
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jmp s y s c a l l _ e x i t
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CFI_ E N D P R O C
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/ *
* Return t o u s e r m o d e i s n o t a s c o m p l e x a s a l l t h i s l o o k s ,
* but w e w a n t t h e d e f a u l t p a t h f o r a s y s t e m c a l l r e t u r n t o
* go a s q u i c k l y a s p o s s i b l e w h i c h i s w h y s o m e o f t h i s i s
* less c l e a r t h a n i t o t h e r w i s e s h o u l d b e .
* /
# userspace r e s u m p t i o n s t u b b y p a s s i n g s y s c a l l e x i t t r a c i n g
ALIGN
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RING0 _ P T R E G S _ F R A M E
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ret_from_exception :
preempt_ s t o p
ret_from_intr :
GET_ T H R E A D _ I N F O ( % e b p )
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check_userspace :
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movl E F L A G S ( % e s p ) , % e a x # m i x E F L A G S a n d C S
movb C S ( % e s p ) , % a l
testl $ ( V M _ M A S K | 3 ) , % e a x
jz r e s u m e _ k e r n e l
ENTRY( r e s u m e _ u s e r s p a c e )
cli # m a k e s u r e w e d o n ' t m i s s a n i n t e r r u p t
# setting n e e d _ r e s c h e d o r s i g p e n d i n g
# between s a m p l i n g a n d t h e i r e t
movl T I _ f l a g s ( % e b p ) , % e c x
andl $ _ T I F _ W O R K _ M A S K , % e c x # i s t h e r e a n y w o r k t o b e d o n e o n
# int/ e x c e p t i o n r e t u r n ?
jne w o r k _ p e n d i n g
jmp r e s t o r e _ a l l
# ifdef C O N F I G _ P R E E M P T
ENTRY( r e s u m e _ k e r n e l )
cli
cmpl $ 0 ,T I _ p r e e m p t _ c o u n t ( % e b p ) # n o n - z e r o p r e e m p t _ c o u n t ?
jnz r e s t o r e _ n o c h e c k
need_resched :
movl T I _ f l a g s ( % e b p ) , % e c x # n e e d _ r e s c h e d s e t ?
testb $ _ T I F _ N E E D _ R E S C H E D , % c l
jz r e s t o r e _ a l l
testl $ I F _ M A S K ,E F L A G S ( % e s p ) # i n t e r r u p t s o f f ( e x c e p t i o n p a t h ) ?
jz r e s t o r e _ a l l
call p r e e m p t _ s c h e d u l e _ i r q
jmp n e e d _ r e s c h e d
# endif
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CFI_ E N D P R O C
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/ * SYSENTER_ R E T U R N p o i n t s t o a f t e r t h e " s y s e n t e r " i n s t r u c t i o n i n
the v s y s c a l l p a g e . S e e v s y s c a l l - s y s e n t r y . S , w h i c h d e f i n e s t h e s y m b o l . * /
# sysenter c a l l h a n d l e r s t u b
ENTRY( s y s e n t e r _ e n t r y )
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CFI_ S T A R T P R O C s i m p l e
CFI_ D E F _ C F A e s p , 0
CFI_ R E G I S T E R e s p , e b p
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movl T S S _ s y s e n t e r _ e s p0 ( % e s p ) ,% e s p
sysenter_past_esp :
sti
pushl $ ( _ _ U S E R _ D S )
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CFI_ A D J U S T _ C F A _ O F F S E T 4
/*CFI_REL_OFFSET ss, 0*/
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pushl % e b p
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CFI_ A D J U S T _ C F A _ O F F S E T 4
CFI_ R E L _ O F F S E T e s p , 0
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pushfl
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CFI_ A D J U S T _ C F A _ O F F S E T 4
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pushl $ ( _ _ U S E R _ C S )
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CFI_ A D J U S T _ C F A _ O F F S E T 4
/*CFI_REL_OFFSET cs, 0*/
[PATCH] vdso: randomize the i386 vDSO by moving it into a vma
Move the i386 VDSO down into a vma and thus randomize it.
Besides the security implications, this feature also helps debuggers, which
can COW a vma-backed VDSO just like a normal DSO and can thus do
single-stepping and other debugging features.
It's good for hypervisors (Xen, VMWare) too, which typically live in the same
high-mapped address space as the VDSO, hence whenever the VDSO is used, they
get lots of guest pagefaults and have to fix such guest accesses up - which
slows things down instead of speeding things up (the primary purpose of the
VDSO).
There's a new CONFIG_COMPAT_VDSO (default=y) option, which provides support
for older glibcs that still rely on a prelinked high-mapped VDSO. Newer
distributions (using glibc 2.3.3 or later) can turn this option off. Turning
it off is also recommended for security reasons: attackers cannot use the
predictable high-mapped VDSO page as syscall trampoline anymore.
There is a new vdso=[0|1] boot option as well, and a runtime
/proc/sys/vm/vdso_enabled sysctl switch, that allows the VDSO to be turned
on/off.
(This version of the VDSO-randomization patch also has working ELF
coredumping, the previous patch crashed in the coredumping code.)
This code is a combined work of the exec-shield VDSO randomization
code and Gerd Hoffmann's hypervisor-centric VDSO patch. Rusty Russell
started this patch and i completed it.
[akpm@osdl.org: cleanups]
[akpm@osdl.org: compile fix]
[akpm@osdl.org: compile fix 2]
[akpm@osdl.org: compile fix 3]
[akpm@osdl.org: revernt MAXMEM change]
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Arjan van de Ven <arjan@infradead.org>
Cc: Gerd Hoffmann <kraxel@suse.de>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Zachary Amsden <zach@vmware.com>
Cc: Andi Kleen <ak@muc.de>
Cc: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-27 13:53:50 +04:00
/ *
* Push c u r r e n t _ t h r e a d _ i n f o ( ) - > s y s e n t e r _ r e t u r n t o t h e s t a c k .
* A t i n y b i t o f o f f s e t f i x u p i s n e c e s s a r y - 4 * 4 m e a n s t h e 4 w o r d s
* pushed a b o v e ; +8 corresponds to copy_thread's esp0 setting.
* /
pushl ( T I _ s y s e n t e r _ r e t u r n - T H R E A D _ S I Z E + 8 + 4 * 4 ) ( % e s p )
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CFI_ A D J U S T _ C F A _ O F F S E T 4
CFI_ R E L _ O F F S E T e i p , 0
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/ *
* Load t h e p o t e n t i a l s i x t h a r g u m e n t f r o m u s e r s t a c k .
* Careful a b o u t s e c u r i t y .
* /
cmpl $ _ _ P A G E _ O F F S E T - 3 ,% e b p
jae s y s c a l l _ f a u l t
1 : movl ( % e b p ) ,% e b p
.section _ _ ex_ t a b l e ," a "
.align 4
.long 1 b,s y s c a l l _ f a u l t
.previous
pushl % e a x
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CFI_ A D J U S T _ C F A _ O F F S E T 4
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SAVE_ A L L
GET_ T H R E A D _ I N F O ( % e b p )
/* Note, _TIF_SECCOMP is bit number 8, and so it needs testw and not testb */
[PATCH] UML Support - Ptrace: adds the host SYSEMU support, for UML and general usage
Jeff Dike <jdike@addtoit.com>,
Paolo 'Blaisorblade' Giarrusso <blaisorblade_spam@yahoo.it>,
Bodo Stroesser <bstroesser@fujitsu-siemens.com>
Adds a new ptrace(2) mode, called PTRACE_SYSEMU, resembling PTRACE_SYSCALL
except that the kernel does not execute the requested syscall; this is useful
to improve performance for virtual environments, like UML, which want to run
the syscall on their own.
In fact, using PTRACE_SYSCALL means stopping child execution twice, on entry
and on exit, and each time you also have two context switches; with SYSEMU you
avoid the 2nd stop and so save two context switches per syscall.
Also, some architectures don't have support in the host for changing the
syscall number via ptrace(), which is currently needed to skip syscall
execution (UML turns any syscall into getpid() to avoid it being executed on
the host). Fixing that is hard, while SYSEMU is easier to implement.
* This version of the patch includes some suggestions of Jeff Dike to avoid
adding any instructions to the syscall fast path, plus some other little
changes, by myself, to make it work even when the syscall is executed with
SYSENTER (but I'm unsure about them). It has been widely tested for quite a
lot of time.
* Various fixed were included to handle the various switches between
various states, i.e. when for instance a syscall entry is traced with one of
PT_SYSCALL / _SYSEMU / _SINGLESTEP and another one is used on exit.
Basically, this is done by remembering which one of them was used even after
the call to ptrace_notify().
* We're combining TIF_SYSCALL_EMU with TIF_SYSCALL_TRACE or TIF_SINGLESTEP
to make do_syscall_trace() notice that the current syscall was started with
SYSEMU on entry, so that no notification ought to be done in the exit path;
this is a bit of a hack, so this problem is solved in another way in next
patches.
* Also, the effects of the patch:
"Ptrace - i386: fix Syscall Audit interaction with singlestep"
are cancelled; they are restored back in the last patch of this series.
Detailed descriptions of the patches doing this kind of processing follow (but
I've already summed everything up).
* Fix behaviour when changing interception kind #1.
In do_syscall_trace(), we check the status of the TIF_SYSCALL_EMU flag
only after doing the debugger notification; but the debugger might have
changed the status of this flag because he continued execution with
PTRACE_SYSCALL, so this is wrong. This patch fixes it by saving the flag
status before calling ptrace_notify().
* Fix behaviour when changing interception kind #2:
avoid intercepting syscall on return when using SYSCALL again.
A guest process switching from using PTRACE_SYSEMU to PTRACE_SYSCALL
crashes.
The problem is in arch/i386/kernel/entry.S. The current SYSEMU patch
inhibits the syscall-handler to be called, but does not prevent
do_syscall_trace() to be called after this for syscall completion
interception.
The appended patch fixes this. It reuses the flag TIF_SYSCALL_EMU to
remember "we come from PTRACE_SYSEMU and now are in PTRACE_SYSCALL", since
the flag is unused in the depicted situation.
* Fix behaviour when changing interception kind #3:
avoid intercepting syscall on return when using SINGLESTEP.
When testing 2.6.9 and the skas3.v6 patch, with my latest patch and had
problems with singlestepping on UML in SKAS with SYSEMU. It looped
receiving SIGTRAPs without moving forward. EIP of the traced process was
the same for all SIGTRAPs.
What's missing is to handle switching from PTRACE_SYSCALL_EMU to
PTRACE_SINGLESTEP in a way very similar to what is done for the change from
PTRACE_SYSCALL_EMU to PTRACE_SYSCALL_TRACE.
I.e., after calling ptrace(PTRACE_SYSEMU), on the return path, the debugger is
notified and then wake ups the process; the syscall is executed (or skipped,
when do_syscall_trace() returns 0, i.e. when using PTRACE_SYSEMU), and
do_syscall_trace() is called again. Since we are on the return path of a
SYSEMU'd syscall, if the wake up is performed through ptrace(PTRACE_SYSCALL),
we must still avoid notifying the parent of the syscall exit. Now, this
behaviour is extended even to resuming with PTRACE_SINGLESTEP.
Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Cc: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-04 02:57:18 +04:00
testw $ ( _ T I F _ S Y S C A L L _ E M U | _ T I F _ S Y S C A L L _ T R A C E | _ T I F _ S E C C O M P | _ T I F _ S Y S C A L L _ A U D I T ) ,T I _ f l a g s ( % e b p )
2005-04-17 02:20:36 +04:00
jnz s y s c a l l _ t r a c e _ e n t r y
cmpl $ ( n r _ s y s c a l l s ) , % e a x
jae s y s c a l l _ b a d s y s
call * s y s _ c a l l _ t a b l e ( ,% e a x ,4 )
movl % e a x ,E A X ( % e s p )
cli
movl T I _ f l a g s ( % e b p ) , % e c x
testw $ _ T I F _ A L L W O R K _ M A S K , % c x
jne s y s c a l l _ e x i t _ w o r k
/* if something modifies registers it must also disable sysexit */
movl E I P ( % e s p ) , % e d x
movl O L D E S P ( % e s p ) , % e c x
xorl % e b p ,% e b p
sti
sysexit
2006-06-26 15:57:44 +04:00
CFI_ E N D P R O C
2005-04-17 02:20:36 +04:00
# system c a l l h a n d l e r s t u b
ENTRY( s y s t e m _ c a l l )
2006-06-26 15:57:44 +04:00
RING0 _ I N T _ F R A M E # c a n ' t u n w i n d i n t o u s e r s p a c e a n y w a y
2005-04-17 02:20:36 +04:00
pushl % e a x # s a v e o r i g _ e a x
2006-06-26 15:57:44 +04:00
CFI_ A D J U S T _ C F A _ O F F S E T 4
2005-04-17 02:20:36 +04:00
SAVE_ A L L
GET_ T H R E A D _ I N F O ( % e b p )
[PATCH] i386: fix singlestep through an int80 syscall
Using PTRACE_SINGLESTEP on a child that does an int80 syscall misses the
SIGTRAP that should be delivered upon syscall exit. Fix that by setting
TIF_SINGLESTEP when entering the kernel via int80 with TF set.
/* Test whether singlestep through an int80 syscall works.
*/
#define _GNU_SOURCE
#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/ptrace.h>
#include <sys/wait.h>
#include <sys/mman.h>
#include <asm/user.h>
static int child, status;
static struct user_regs_struct regs;
static void do_child()
{
ptrace(PTRACE_TRACEME, 0, 0, 0);
kill(getpid(), SIGUSR1);
asm ("int $0x80" : : "a" (20)); /* getpid */
}
static void do_parent()
{
unsigned long eip, expected = 0;
again:
waitpid(child, &status, 0);
if (WIFEXITED(status) || WIFSIGNALED(status))
return;
if (WIFSTOPPED(status)) {
ptrace(PTRACE_GETREGS, child, 0, ®s);
eip = regs.eip;
if (expected)
fprintf(stderr, "child stop @ %08x, expected %08x %s\n",
eip, expected,
eip == expected ? "" : " <== ERROR");
if (*(unsigned short *)eip == 0x80cd) {
fprintf(stderr, "int 0x80 at %08x\n", (unsigned int)eip);
expected = eip + 2;
} else
expected = 0;
ptrace(PTRACE_SINGLESTEP, child, NULL, NULL);
}
goto again;
}
int main(int argc, char * const argv[])
{
child = fork();
if (child)
do_parent();
else
do_child();
return 0;
}
Signed-off-by: Chuck Ebbert <76306.1226@compuserve.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-23 13:59:48 +03:00
testl $ T F _ M A S K ,E F L A G S ( % e s p )
jz n o _ s i n g l e s t e p
orl $ _ T I F _ S I N G L E S T E P ,T I _ f l a g s ( % e b p )
no_singlestep :
[PATCH] UML Support - Ptrace: adds the host SYSEMU support, for UML and general usage
Jeff Dike <jdike@addtoit.com>,
Paolo 'Blaisorblade' Giarrusso <blaisorblade_spam@yahoo.it>,
Bodo Stroesser <bstroesser@fujitsu-siemens.com>
Adds a new ptrace(2) mode, called PTRACE_SYSEMU, resembling PTRACE_SYSCALL
except that the kernel does not execute the requested syscall; this is useful
to improve performance for virtual environments, like UML, which want to run
the syscall on their own.
In fact, using PTRACE_SYSCALL means stopping child execution twice, on entry
and on exit, and each time you also have two context switches; with SYSEMU you
avoid the 2nd stop and so save two context switches per syscall.
Also, some architectures don't have support in the host for changing the
syscall number via ptrace(), which is currently needed to skip syscall
execution (UML turns any syscall into getpid() to avoid it being executed on
the host). Fixing that is hard, while SYSEMU is easier to implement.
* This version of the patch includes some suggestions of Jeff Dike to avoid
adding any instructions to the syscall fast path, plus some other little
changes, by myself, to make it work even when the syscall is executed with
SYSENTER (but I'm unsure about them). It has been widely tested for quite a
lot of time.
* Various fixed were included to handle the various switches between
various states, i.e. when for instance a syscall entry is traced with one of
PT_SYSCALL / _SYSEMU / _SINGLESTEP and another one is used on exit.
Basically, this is done by remembering which one of them was used even after
the call to ptrace_notify().
* We're combining TIF_SYSCALL_EMU with TIF_SYSCALL_TRACE or TIF_SINGLESTEP
to make do_syscall_trace() notice that the current syscall was started with
SYSEMU on entry, so that no notification ought to be done in the exit path;
this is a bit of a hack, so this problem is solved in another way in next
patches.
* Also, the effects of the patch:
"Ptrace - i386: fix Syscall Audit interaction with singlestep"
are cancelled; they are restored back in the last patch of this series.
Detailed descriptions of the patches doing this kind of processing follow (but
I've already summed everything up).
* Fix behaviour when changing interception kind #1.
In do_syscall_trace(), we check the status of the TIF_SYSCALL_EMU flag
only after doing the debugger notification; but the debugger might have
changed the status of this flag because he continued execution with
PTRACE_SYSCALL, so this is wrong. This patch fixes it by saving the flag
status before calling ptrace_notify().
* Fix behaviour when changing interception kind #2:
avoid intercepting syscall on return when using SYSCALL again.
A guest process switching from using PTRACE_SYSEMU to PTRACE_SYSCALL
crashes.
The problem is in arch/i386/kernel/entry.S. The current SYSEMU patch
inhibits the syscall-handler to be called, but does not prevent
do_syscall_trace() to be called after this for syscall completion
interception.
The appended patch fixes this. It reuses the flag TIF_SYSCALL_EMU to
remember "we come from PTRACE_SYSEMU and now are in PTRACE_SYSCALL", since
the flag is unused in the depicted situation.
* Fix behaviour when changing interception kind #3:
avoid intercepting syscall on return when using SINGLESTEP.
When testing 2.6.9 and the skas3.v6 patch, with my latest patch and had
problems with singlestepping on UML in SKAS with SYSEMU. It looped
receiving SIGTRAPs without moving forward. EIP of the traced process was
the same for all SIGTRAPs.
What's missing is to handle switching from PTRACE_SYSCALL_EMU to
PTRACE_SINGLESTEP in a way very similar to what is done for the change from
PTRACE_SYSCALL_EMU to PTRACE_SYSCALL_TRACE.
I.e., after calling ptrace(PTRACE_SYSEMU), on the return path, the debugger is
notified and then wake ups the process; the syscall is executed (or skipped,
when do_syscall_trace() returns 0, i.e. when using PTRACE_SYSEMU), and
do_syscall_trace() is called again. Since we are on the return path of a
SYSEMU'd syscall, if the wake up is performed through ptrace(PTRACE_SYSCALL),
we must still avoid notifying the parent of the syscall exit. Now, this
behaviour is extended even to resuming with PTRACE_SINGLESTEP.
Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Cc: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-04 02:57:18 +04:00
# system c a l l t r a c i n g i n o p e r a t i o n / e m u l a t i o n
2005-04-17 02:20:36 +04:00
/* Note, _TIF_SECCOMP is bit number 8, and so it needs testw and not testb */
[PATCH] UML Support - Ptrace: adds the host SYSEMU support, for UML and general usage
Jeff Dike <jdike@addtoit.com>,
Paolo 'Blaisorblade' Giarrusso <blaisorblade_spam@yahoo.it>,
Bodo Stroesser <bstroesser@fujitsu-siemens.com>
Adds a new ptrace(2) mode, called PTRACE_SYSEMU, resembling PTRACE_SYSCALL
except that the kernel does not execute the requested syscall; this is useful
to improve performance for virtual environments, like UML, which want to run
the syscall on their own.
In fact, using PTRACE_SYSCALL means stopping child execution twice, on entry
and on exit, and each time you also have two context switches; with SYSEMU you
avoid the 2nd stop and so save two context switches per syscall.
Also, some architectures don't have support in the host for changing the
syscall number via ptrace(), which is currently needed to skip syscall
execution (UML turns any syscall into getpid() to avoid it being executed on
the host). Fixing that is hard, while SYSEMU is easier to implement.
* This version of the patch includes some suggestions of Jeff Dike to avoid
adding any instructions to the syscall fast path, plus some other little
changes, by myself, to make it work even when the syscall is executed with
SYSENTER (but I'm unsure about them). It has been widely tested for quite a
lot of time.
* Various fixed were included to handle the various switches between
various states, i.e. when for instance a syscall entry is traced with one of
PT_SYSCALL / _SYSEMU / _SINGLESTEP and another one is used on exit.
Basically, this is done by remembering which one of them was used even after
the call to ptrace_notify().
* We're combining TIF_SYSCALL_EMU with TIF_SYSCALL_TRACE or TIF_SINGLESTEP
to make do_syscall_trace() notice that the current syscall was started with
SYSEMU on entry, so that no notification ought to be done in the exit path;
this is a bit of a hack, so this problem is solved in another way in next
patches.
* Also, the effects of the patch:
"Ptrace - i386: fix Syscall Audit interaction with singlestep"
are cancelled; they are restored back in the last patch of this series.
Detailed descriptions of the patches doing this kind of processing follow (but
I've already summed everything up).
* Fix behaviour when changing interception kind #1.
In do_syscall_trace(), we check the status of the TIF_SYSCALL_EMU flag
only after doing the debugger notification; but the debugger might have
changed the status of this flag because he continued execution with
PTRACE_SYSCALL, so this is wrong. This patch fixes it by saving the flag
status before calling ptrace_notify().
* Fix behaviour when changing interception kind #2:
avoid intercepting syscall on return when using SYSCALL again.
A guest process switching from using PTRACE_SYSEMU to PTRACE_SYSCALL
crashes.
The problem is in arch/i386/kernel/entry.S. The current SYSEMU patch
inhibits the syscall-handler to be called, but does not prevent
do_syscall_trace() to be called after this for syscall completion
interception.
The appended patch fixes this. It reuses the flag TIF_SYSCALL_EMU to
remember "we come from PTRACE_SYSEMU and now are in PTRACE_SYSCALL", since
the flag is unused in the depicted situation.
* Fix behaviour when changing interception kind #3:
avoid intercepting syscall on return when using SINGLESTEP.
When testing 2.6.9 and the skas3.v6 patch, with my latest patch and had
problems with singlestepping on UML in SKAS with SYSEMU. It looped
receiving SIGTRAPs without moving forward. EIP of the traced process was
the same for all SIGTRAPs.
What's missing is to handle switching from PTRACE_SYSCALL_EMU to
PTRACE_SINGLESTEP in a way very similar to what is done for the change from
PTRACE_SYSCALL_EMU to PTRACE_SYSCALL_TRACE.
I.e., after calling ptrace(PTRACE_SYSEMU), on the return path, the debugger is
notified and then wake ups the process; the syscall is executed (or skipped,
when do_syscall_trace() returns 0, i.e. when using PTRACE_SYSEMU), and
do_syscall_trace() is called again. Since we are on the return path of a
SYSEMU'd syscall, if the wake up is performed through ptrace(PTRACE_SYSCALL),
we must still avoid notifying the parent of the syscall exit. Now, this
behaviour is extended even to resuming with PTRACE_SINGLESTEP.
Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Cc: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-04 02:57:18 +04:00
testw $ ( _ T I F _ S Y S C A L L _ E M U | _ T I F _ S Y S C A L L _ T R A C E | _ T I F _ S E C C O M P | _ T I F _ S Y S C A L L _ A U D I T ) ,T I _ f l a g s ( % e b p )
2005-04-17 02:20:36 +04:00
jnz s y s c a l l _ t r a c e _ e n t r y
cmpl $ ( n r _ s y s c a l l s ) , % e a x
jae s y s c a l l _ b a d s y s
syscall_call :
call * s y s _ c a l l _ t a b l e ( ,% e a x ,4 )
movl % e a x ,E A X ( % e s p ) # s t o r e t h e r e t u r n v a l u e
syscall_exit :
cli # m a k e s u r e w e d o n ' t m i s s a n i n t e r r u p t
# setting n e e d _ r e s c h e d o r s i g p e n d i n g
# between s a m p l i n g a n d t h e i r e t
movl T I _ f l a g s ( % e b p ) , % e c x
testw $ _ T I F _ A L L W O R K _ M A S K , % c x # c u r r e n t - > w o r k
jne s y s c a l l _ e x i t _ w o r k
restore_all :
movl E F L A G S ( % e s p ) , % e a x # m i x E F L A G S , S S a n d C S
2005-04-17 02:24:01 +04:00
# Warning : OLDSS( % e s p ) c o n t a i n s t h e w r o n g / r a n d o m v a l u e s i f w e
# are r e t u r n i n g t o t h e k e r n e l .
# See c o m m e n t s i n p r o c e s s . c : c o p y _ t h r e a d ( ) f o r d e t a i l s .
2005-04-17 02:20:36 +04:00
movb O L D S S ( % e s p ) , % a h
movb C S ( % e s p ) , % a l
andl $ ( V M _ M A S K | ( 4 < < 8 ) | 3 ) , % e a x
cmpl $ ( ( 4 < < 8 ) | 3 ) , % e a x
2006-06-26 15:57:44 +04:00
CFI_ R E M E M B E R _ S T A T E
2005-04-17 02:20:36 +04:00
je l d t _ s s # r e t u r n i n g t o u s e r - s p a c e w i t h L D T S S
restore_nocheck :
RESTORE_ R E G S
addl $ 4 , % e s p
2006-06-26 15:57:44 +04:00
CFI_ A D J U S T _ C F A _ O F F S E T - 4
2005-04-17 02:20:36 +04:00
1 : iret
.section .fixup , " ax"
iret_exc :
sti
2005-04-29 20:38:44 +04:00
pushl $ 0 # n o e r r o r c o d e
pushl $ d o _ i r e t _ e r r o r
jmp e r r o r _ c o d e
2005-04-17 02:20:36 +04:00
.previous
.section _ _ ex_ t a b l e ," a "
.align 4
.long 1 b,i r e t _ e x c
.previous
2006-06-26 15:57:44 +04:00
CFI_ R E S T O R E _ S T A T E
2005-04-17 02:20:36 +04:00
ldt_ss :
larl O L D S S ( % e s p ) , % e a x
jnz r e s t o r e _ n o c h e c k
testl $ 0 x00 4 0 0 0 0 0 , % e a x # r e t u r n i n g t o 32 b i t s t a c k ?
jnz r e s t o r e _ n o c h e c k # a l l r i g h t , n o r m a l r e t u r n
/ * If r e t u r n i n g t o u s e r s p a c e w i t h 1 6 b i t s t a c k ,
* try t o f i x t h e h i g h e r w o r d o f E S P , a s t h e C P U
* won' t r e s t o r e i t .
* This i s a n " o f f i c i a l " b u g o f a l l t h e x86 - c o m p a t i b l e
* CPUs, w h i c h w e c a n t r y t o w o r k a r o u n d t o m a k e
* dosemu a n d w i n e h a p p y . * /
subl $ 8 , % e s p # r e s e r v e s p a c e f o r s w i t c h 16 p o i n t e r
2006-06-26 15:57:44 +04:00
CFI_ A D J U S T _ C F A _ O F F S E T 8
2005-04-17 02:20:36 +04:00
cli
movl % e s p , % e a x
/ * Set u p t h e 1 6 b i t s t a c k f r a m e w i t h s w i t c h32 p o i n t e r o n t o p ,
* and a s w i t c h16 p o i n t e r o n t o p o f t h e c u r r e n t f r a m e . * /
call s e t u p _ x86 _ b o g u s _ s t a c k
2006-06-26 15:57:44 +04:00
CFI_ A D J U S T _ C F A _ O F F S E T - 8 # f r a m e h a s m o v e d
2005-04-17 02:20:36 +04:00
RESTORE_ R E G S
lss 2 0 + 4 ( % e s p ) , % e s p # s w i t c h t o 16 b i t s t a c k
1 : iret
.section _ _ ex_ t a b l e ," a "
.align 4
.long 1 b,i r e t _ e x c
.previous
2006-06-26 15:57:44 +04:00
CFI_ E N D P R O C
2005-04-17 02:20:36 +04:00
# perform w o r k t h a t n e e d s t o b e d o n e i m m e d i a t e l y b e f o r e r e s u m p t i o n
ALIGN
2006-06-26 15:57:44 +04:00
RING0 _ P T R E G S _ F R A M E # c a n ' t u n w i n d i n t o u s e r s p a c e a n y w a y
2005-04-17 02:20:36 +04:00
work_pending :
testb $ _ T I F _ N E E D _ R E S C H E D , % c l
jz w o r k _ n o t i f y s i g
work_resched :
call s c h e d u l e
cli # m a k e s u r e w e d o n ' t m i s s a n i n t e r r u p t
# setting n e e d _ r e s c h e d o r s i g p e n d i n g
# between s a m p l i n g a n d t h e i r e t
movl T I _ f l a g s ( % e b p ) , % e c x
andl $ _ T I F _ W O R K _ M A S K , % e c x # i s t h e r e a n y w o r k t o b e d o n e o t h e r
# than s y s c a l l t r a c i n g ?
jz r e s t o r e _ a l l
testb $ _ T I F _ N E E D _ R E S C H E D , % c l
jnz w o r k _ r e s c h e d
work_notifysig : # deal w i t h p e n d i n g s i g n a l s a n d
# notify- r e s u m e r e q u e s t s
testl $ V M _ M A S K , E F L A G S ( % e s p )
movl % e s p , % e a x
jne w o r k _ n o t i f y s i g _ v86 # r e t u r n i n g t o k e r n e l - s p a c e o r
# vm8 6 - s p a c e
xorl % e d x , % e d x
call d o _ n o t i f y _ r e s u m e
2006-06-27 13:53:48 +04:00
jmp r e s u m e _ u s e r s p a c e _ s i g
2005-04-17 02:20:36 +04:00
ALIGN
work_notifysig_v86 :
2006-01-08 12:05:26 +03:00
# ifdef C O N F I G _ V M 8 6
2005-04-17 02:20:36 +04:00
pushl % e c x # s a v e t i _ f l a g s f o r d o _ n o t i f y _ r e s u m e
2006-06-26 15:57:44 +04:00
CFI_ A D J U S T _ C F A _ O F F S E T 4
2005-04-17 02:20:36 +04:00
call s a v e _ v86 _ s t a t e # % e a x c o n t a i n s p t _ r e g s p o i n t e r
popl % e c x
2006-06-26 15:57:44 +04:00
CFI_ A D J U S T _ C F A _ O F F S E T - 4
2005-04-17 02:20:36 +04:00
movl % e a x , % e s p
xorl % e d x , % e d x
call d o _ n o t i f y _ r e s u m e
2006-06-27 13:53:48 +04:00
jmp r e s u m e _ u s e r s p a c e _ s i g
2006-01-08 12:05:26 +03:00
# endif
2005-04-17 02:20:36 +04:00
# perform s y s c a l l e x i t t r a c i n g
ALIGN
syscall_trace_entry :
movl $ - E N O S Y S ,E A X ( % e s p )
movl % e s p , % e a x
xorl % e d x ,% e d x
call d o _ s y s c a l l _ t r a c e
[PATCH] UML Support - Ptrace: adds the host SYSEMU support, for UML and general usage
Jeff Dike <jdike@addtoit.com>,
Paolo 'Blaisorblade' Giarrusso <blaisorblade_spam@yahoo.it>,
Bodo Stroesser <bstroesser@fujitsu-siemens.com>
Adds a new ptrace(2) mode, called PTRACE_SYSEMU, resembling PTRACE_SYSCALL
except that the kernel does not execute the requested syscall; this is useful
to improve performance for virtual environments, like UML, which want to run
the syscall on their own.
In fact, using PTRACE_SYSCALL means stopping child execution twice, on entry
and on exit, and each time you also have two context switches; with SYSEMU you
avoid the 2nd stop and so save two context switches per syscall.
Also, some architectures don't have support in the host for changing the
syscall number via ptrace(), which is currently needed to skip syscall
execution (UML turns any syscall into getpid() to avoid it being executed on
the host). Fixing that is hard, while SYSEMU is easier to implement.
* This version of the patch includes some suggestions of Jeff Dike to avoid
adding any instructions to the syscall fast path, plus some other little
changes, by myself, to make it work even when the syscall is executed with
SYSENTER (but I'm unsure about them). It has been widely tested for quite a
lot of time.
* Various fixed were included to handle the various switches between
various states, i.e. when for instance a syscall entry is traced with one of
PT_SYSCALL / _SYSEMU / _SINGLESTEP and another one is used on exit.
Basically, this is done by remembering which one of them was used even after
the call to ptrace_notify().
* We're combining TIF_SYSCALL_EMU with TIF_SYSCALL_TRACE or TIF_SINGLESTEP
to make do_syscall_trace() notice that the current syscall was started with
SYSEMU on entry, so that no notification ought to be done in the exit path;
this is a bit of a hack, so this problem is solved in another way in next
patches.
* Also, the effects of the patch:
"Ptrace - i386: fix Syscall Audit interaction with singlestep"
are cancelled; they are restored back in the last patch of this series.
Detailed descriptions of the patches doing this kind of processing follow (but
I've already summed everything up).
* Fix behaviour when changing interception kind #1.
In do_syscall_trace(), we check the status of the TIF_SYSCALL_EMU flag
only after doing the debugger notification; but the debugger might have
changed the status of this flag because he continued execution with
PTRACE_SYSCALL, so this is wrong. This patch fixes it by saving the flag
status before calling ptrace_notify().
* Fix behaviour when changing interception kind #2:
avoid intercepting syscall on return when using SYSCALL again.
A guest process switching from using PTRACE_SYSEMU to PTRACE_SYSCALL
crashes.
The problem is in arch/i386/kernel/entry.S. The current SYSEMU patch
inhibits the syscall-handler to be called, but does not prevent
do_syscall_trace() to be called after this for syscall completion
interception.
The appended patch fixes this. It reuses the flag TIF_SYSCALL_EMU to
remember "we come from PTRACE_SYSEMU and now are in PTRACE_SYSCALL", since
the flag is unused in the depicted situation.
* Fix behaviour when changing interception kind #3:
avoid intercepting syscall on return when using SINGLESTEP.
When testing 2.6.9 and the skas3.v6 patch, with my latest patch and had
problems with singlestepping on UML in SKAS with SYSEMU. It looped
receiving SIGTRAPs without moving forward. EIP of the traced process was
the same for all SIGTRAPs.
What's missing is to handle switching from PTRACE_SYSCALL_EMU to
PTRACE_SINGLESTEP in a way very similar to what is done for the change from
PTRACE_SYSCALL_EMU to PTRACE_SYSCALL_TRACE.
I.e., after calling ptrace(PTRACE_SYSEMU), on the return path, the debugger is
notified and then wake ups the process; the syscall is executed (or skipped,
when do_syscall_trace() returns 0, i.e. when using PTRACE_SYSEMU), and
do_syscall_trace() is called again. Since we are on the return path of a
SYSEMU'd syscall, if the wake up is performed through ptrace(PTRACE_SYSCALL),
we must still avoid notifying the parent of the syscall exit. Now, this
behaviour is extended even to resuming with PTRACE_SINGLESTEP.
Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Cc: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-04 02:57:18 +04:00
cmpl $ 0 , % e a x
2005-09-04 02:57:22 +04:00
jne r e s u m e _ u s e r s p a c e # r e t ! = 0 - > r u n n i n g u n d e r P T R A C E _ S Y S E M U ,
[PATCH] UML Support - Ptrace: adds the host SYSEMU support, for UML and general usage
Jeff Dike <jdike@addtoit.com>,
Paolo 'Blaisorblade' Giarrusso <blaisorblade_spam@yahoo.it>,
Bodo Stroesser <bstroesser@fujitsu-siemens.com>
Adds a new ptrace(2) mode, called PTRACE_SYSEMU, resembling PTRACE_SYSCALL
except that the kernel does not execute the requested syscall; this is useful
to improve performance for virtual environments, like UML, which want to run
the syscall on their own.
In fact, using PTRACE_SYSCALL means stopping child execution twice, on entry
and on exit, and each time you also have two context switches; with SYSEMU you
avoid the 2nd stop and so save two context switches per syscall.
Also, some architectures don't have support in the host for changing the
syscall number via ptrace(), which is currently needed to skip syscall
execution (UML turns any syscall into getpid() to avoid it being executed on
the host). Fixing that is hard, while SYSEMU is easier to implement.
* This version of the patch includes some suggestions of Jeff Dike to avoid
adding any instructions to the syscall fast path, plus some other little
changes, by myself, to make it work even when the syscall is executed with
SYSENTER (but I'm unsure about them). It has been widely tested for quite a
lot of time.
* Various fixed were included to handle the various switches between
various states, i.e. when for instance a syscall entry is traced with one of
PT_SYSCALL / _SYSEMU / _SINGLESTEP and another one is used on exit.
Basically, this is done by remembering which one of them was used even after
the call to ptrace_notify().
* We're combining TIF_SYSCALL_EMU with TIF_SYSCALL_TRACE or TIF_SINGLESTEP
to make do_syscall_trace() notice that the current syscall was started with
SYSEMU on entry, so that no notification ought to be done in the exit path;
this is a bit of a hack, so this problem is solved in another way in next
patches.
* Also, the effects of the patch:
"Ptrace - i386: fix Syscall Audit interaction with singlestep"
are cancelled; they are restored back in the last patch of this series.
Detailed descriptions of the patches doing this kind of processing follow (but
I've already summed everything up).
* Fix behaviour when changing interception kind #1.
In do_syscall_trace(), we check the status of the TIF_SYSCALL_EMU flag
only after doing the debugger notification; but the debugger might have
changed the status of this flag because he continued execution with
PTRACE_SYSCALL, so this is wrong. This patch fixes it by saving the flag
status before calling ptrace_notify().
* Fix behaviour when changing interception kind #2:
avoid intercepting syscall on return when using SYSCALL again.
A guest process switching from using PTRACE_SYSEMU to PTRACE_SYSCALL
crashes.
The problem is in arch/i386/kernel/entry.S. The current SYSEMU patch
inhibits the syscall-handler to be called, but does not prevent
do_syscall_trace() to be called after this for syscall completion
interception.
The appended patch fixes this. It reuses the flag TIF_SYSCALL_EMU to
remember "we come from PTRACE_SYSEMU and now are in PTRACE_SYSCALL", since
the flag is unused in the depicted situation.
* Fix behaviour when changing interception kind #3:
avoid intercepting syscall on return when using SINGLESTEP.
When testing 2.6.9 and the skas3.v6 patch, with my latest patch and had
problems with singlestepping on UML in SKAS with SYSEMU. It looped
receiving SIGTRAPs without moving forward. EIP of the traced process was
the same for all SIGTRAPs.
What's missing is to handle switching from PTRACE_SYSCALL_EMU to
PTRACE_SINGLESTEP in a way very similar to what is done for the change from
PTRACE_SYSCALL_EMU to PTRACE_SYSCALL_TRACE.
I.e., after calling ptrace(PTRACE_SYSEMU), on the return path, the debugger is
notified and then wake ups the process; the syscall is executed (or skipped,
when do_syscall_trace() returns 0, i.e. when using PTRACE_SYSEMU), and
do_syscall_trace() is called again. Since we are on the return path of a
SYSEMU'd syscall, if the wake up is performed through ptrace(PTRACE_SYSCALL),
we must still avoid notifying the parent of the syscall exit. Now, this
behaviour is extended even to resuming with PTRACE_SINGLESTEP.
Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Cc: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-04 02:57:18 +04:00
# so m u s t s k i p a c t u a l s y s c a l l
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movl O R I G _ E A X ( % e s p ) , % e a x
cmpl $ ( n r _ s y s c a l l s ) , % e a x
jnae s y s c a l l _ c a l l
jmp s y s c a l l _ e x i t
# perform s y s c a l l e x i t t r a c i n g
ALIGN
syscall_exit_work :
testb $ ( _ T I F _ S Y S C A L L _ T R A C E | _ T I F _ S Y S C A L L _ A U D I T | _ T I F _ S I N G L E S T E P ) , % c l
jz w o r k _ p e n d i n g
sti # c o u l d l e t d o _ s y s c a l l _ t r a c e ( ) c a l l
# schedule( ) i n s t e a d
movl % e s p , % e a x
movl $ 1 , % e d x
call d o _ s y s c a l l _ t r a c e
jmp r e s u m e _ u s e r s p a c e
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CFI_ E N D P R O C
2005-04-17 02:20:36 +04:00
2006-06-26 15:57:44 +04:00
RING0 _ I N T _ F R A M E # c a n ' t u n w i n d i n t o u s e r s p a c e a n y w a y
2005-04-17 02:20:36 +04:00
syscall_fault :
pushl % e a x # s a v e o r i g _ e a x
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CFI_ A D J U S T _ C F A _ O F F S E T 4
2005-04-17 02:20:36 +04:00
SAVE_ A L L
GET_ T H R E A D _ I N F O ( % e b p )
movl $ - E F A U L T ,E A X ( % e s p )
jmp r e s u m e _ u s e r s p a c e
syscall_badsys :
movl $ - E N O S Y S ,E A X ( % e s p )
jmp r e s u m e _ u s e r s p a c e
2006-06-26 15:57:44 +04:00
CFI_ E N D P R O C
2005-04-17 02:20:36 +04:00
# define F I X U P _ E S P F I X _ S T A C K \
movl % e s p , % e a x ; \
/* switch to 32bit stack using the pointer on top of 16bit stack */ \
lss % s s : C P U _ 1 6 B I T _ S T A C K _ S I Z E - 8 , % e s p ; \
/* copy data from 16bit stack to 32bit stack */ \
call f i x u p _ x86 _ b o g u s _ s t a c k ; \
/* put ESP to the proper location */ \
movl % e a x , % e s p ;
# define U N W I N D _ E S P F I X _ S T A C K \
pushl % e a x ; \
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CFI_ A D J U S T _ C F A _ O F F S E T 4 ; \
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movl % s s , % e a x ; \
/* see if on 16bit stack */ \
cmpw $ _ _ E S P F I X _ S S , % a x ; \
2006-06-26 15:57:44 +04:00
je 2 8 f ; \
27 : popl % e a x ; \
CFI_ A D J U S T _ C F A _ O F F S E T - 4 ; \
.section .fixup , " ax" ; \
28 : movl $ _ _ K E R N E L _ D S , % e a x ; \
movl % e a x , % d s ; \
movl % e a x , % e s ; \
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/* switch to 32bit stack */ \
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FIXUP_ E S P F I X _ S T A C K ; \
jmp 2 7 b ; \
.previous
2005-04-17 02:20:36 +04:00
/ *
* Build t h e e n t r y s t u b s a n d p o i n t e r t a b l e w i t h
* some a s s e m b l e r m a g i c .
* /
.data
ENTRY( i n t e r r u p t )
.text
vector=0
ENTRY( i r q _ e n t r i e s _ s t a r t )
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RING0 _ I N T _ F R A M E
2005-04-17 02:20:36 +04:00
.rept NR_IRQS
ALIGN
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.if vector
CFI_ A D J U S T _ C F A _ O F F S E T - 4
.endif
2006-06-27 13:53:44 +04:00
1 : pushl $ ~ ( v e c t o r )
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CFI_ A D J U S T _ C F A _ O F F S E T 4
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jmp c o m m o n _ i n t e r r u p t
.data
.long 1b
.text
vector=vector + 1
.endr
ALIGN
common_interrupt :
SAVE_ A L L
movl % e s p ,% e a x
call d o _ I R Q
jmp r e t _ f r o m _ i n t r
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CFI_ E N D P R O C
2005-04-17 02:20:36 +04:00
# define B U I L D _ I N T E R R U P T ( n a m e , n r ) \
ENTRY( n a m e ) \
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RING0 _ I N T _ F R A M E ; \
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pushl $ ~ ( n r ) ; \
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CFI_ A D J U S T _ C F A _ O F F S E T 4 ; \
SAVE_ A L L ; \
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movl % e s p ,% e a x ; \
call s m p _ / * * / n a m e ; \
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jmp r e t _ f r o m _ i n t r ; \
CFI_ E N D P R O C
2005-04-17 02:20:36 +04:00
/* The include is where all of the SMP etc. interrupts come from */
# include " e n t r y _ a r c h . h "
ENTRY( d i v i d e _ e r r o r )
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RING0 _ I N T _ F R A M E
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pushl $ 0 # n o e r r o r c o d e
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CFI_ A D J U S T _ C F A _ O F F S E T 4
2005-04-17 02:20:36 +04:00
pushl $ d o _ d i v i d e _ e r r o r
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CFI_ A D J U S T _ C F A _ O F F S E T 4
2005-04-17 02:20:36 +04:00
ALIGN
error_code :
pushl % d s
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CFI_ A D J U S T _ C F A _ O F F S E T 4
/*CFI_REL_OFFSET ds, 0*/
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pushl % e a x
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CFI_ A D J U S T _ C F A _ O F F S E T 4
CFI_ R E L _ O F F S E T e a x , 0
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xorl % e a x , % e a x
pushl % e b p
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CFI_ A D J U S T _ C F A _ O F F S E T 4
CFI_ R E L _ O F F S E T e b p , 0
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pushl % e d i
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CFI_ A D J U S T _ C F A _ O F F S E T 4
CFI_ R E L _ O F F S E T e d i , 0
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pushl % e s i
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CFI_ A D J U S T _ C F A _ O F F S E T 4
CFI_ R E L _ O F F S E T e s i , 0
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pushl % e d x
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CFI_ A D J U S T _ C F A _ O F F S E T 4
CFI_ R E L _ O F F S E T e d x , 0
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decl % e a x # e a x = - 1
pushl % e c x
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CFI_ A D J U S T _ C F A _ O F F S E T 4
CFI_ R E L _ O F F S E T e c x , 0
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pushl % e b x
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CFI_ A D J U S T _ C F A _ O F F S E T 4
CFI_ R E L _ O F F S E T e b x , 0
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cld
pushl % e s
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CFI_ A D J U S T _ C F A _ O F F S E T 4
/*CFI_REL_OFFSET es, 0*/
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UNWIND_ E S P F I X _ S T A C K
popl % e c x
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CFI_ A D J U S T _ C F A _ O F F S E T - 4
/*CFI_REGISTER es, ecx*/
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movl E S ( % e s p ) , % e d i # g e t t h e f u n c t i o n a d d r e s s
movl O R I G _ E A X ( % e s p ) , % e d x # g e t t h e e r r o r c o d e
movl % e a x , O R I G _ E A X ( % e s p )
movl % e c x , E S ( % e s p )
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/*CFI_REL_OFFSET es, ES*/
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movl $ ( _ _ U S E R _ D S ) , % e c x
movl % e c x , % d s
movl % e c x , % e s
movl % e s p ,% e a x # p t _ r e g s p o i n t e r
call * % e d i
jmp r e t _ f r o m _ e x c e p t i o n
2006-06-26 15:57:44 +04:00
CFI_ E N D P R O C
2005-04-17 02:20:36 +04:00
ENTRY( c o p r o c e s s o r _ e r r o r )
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RING0 _ I N T _ F R A M E
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pushl $ 0
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CFI_ A D J U S T _ C F A _ O F F S E T 4
2005-04-17 02:20:36 +04:00
pushl $ d o _ c o p r o c e s s o r _ e r r o r
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CFI_ A D J U S T _ C F A _ O F F S E T 4
2005-04-17 02:20:36 +04:00
jmp e r r o r _ c o d e
2006-06-26 15:57:44 +04:00
CFI_ E N D P R O C
2005-04-17 02:20:36 +04:00
ENTRY( s i m d _ c o p r o c e s s o r _ e r r o r )
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RING0 _ I N T _ F R A M E
2005-04-17 02:20:36 +04:00
pushl $ 0
2006-06-26 15:57:44 +04:00
CFI_ A D J U S T _ C F A _ O F F S E T 4
2005-04-17 02:20:36 +04:00
pushl $ d o _ s i m d _ c o p r o c e s s o r _ e r r o r
2006-06-26 15:57:44 +04:00
CFI_ A D J U S T _ C F A _ O F F S E T 4
2005-04-17 02:20:36 +04:00
jmp e r r o r _ c o d e
2006-06-26 15:57:44 +04:00
CFI_ E N D P R O C
2005-04-17 02:20:36 +04:00
ENTRY( d e v i c e _ n o t _ a v a i l a b l e )
2006-06-26 15:57:44 +04:00
RING0 _ I N T _ F R A M E
2005-04-17 02:20:36 +04:00
pushl $ - 1 # m a r k t h i s a s a n i n t
2006-06-26 15:57:44 +04:00
CFI_ A D J U S T _ C F A _ O F F S E T 4
2005-04-17 02:20:36 +04:00
SAVE_ A L L
movl % c r0 , % e a x
testl $ 0 x4 , % e a x # E M ( m a t h e m u l a t i o n b i t )
jne d e v i c e _ n o t _ a v a i l a b l e _ e m u l a t e
preempt_ s t o p
call m a t h _ s t a t e _ r e s t o r e
jmp r e t _ f r o m _ e x c e p t i o n
device_not_available_emulate :
pushl $ 0 # t e m p o r a r y s t o r a g e f o r O R I G _ E I P
2006-06-26 15:57:44 +04:00
CFI_ A D J U S T _ C F A _ O F F S E T 4
2005-04-17 02:20:36 +04:00
call m a t h _ e m u l a t e
addl $ 4 , % e s p
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CFI_ A D J U S T _ C F A _ O F F S E T - 4
2005-04-17 02:20:36 +04:00
jmp r e t _ f r o m _ e x c e p t i o n
2006-06-26 15:57:44 +04:00
CFI_ E N D P R O C
2005-04-17 02:20:36 +04:00
/ *
* Debug t r a p s a n d N M I c a n h a p p e n a t t h e o n e S Y S E N T E R i n s t r u c t i o n
* that s e t s u p t h e r e a l k e r n e l s t a c k . C h e c k h e r e , s i n c e w e c a n ' t
* allow t h e w r o n g s t a c k t o b e u s e d .
*
* " TSS_ s y s e n t e r _ e s p0 + 1 2 " i s b e c a u s e t h e N M I / d e b u g h a n d l e r w i l l h a v e
* already p u s h e d 3 w o r d s i f i t h i t s o n t h e s y s e n t e r i n s t r u c t i o n :
* eflags, c s a n d e i p .
*
* We j u s t l o a d t h e r i g h t s t a c k , a n d p u s h t h e t h r e e ( k n o w n ) v a l u e s
* by h a n d o n t o t h e n e w s t a c k - w h i l e u p d a t i n g t h e r e t u r n e i p p a s t
* the i n s t r u c t i o n t h a t w o u l d h a v e d o n e i t f o r s y s e n t e r .
* /
# define F I X _ S T A C K ( o f f s e t , o k , l a b e l ) \
cmpw $ _ _ K E R N E L _ C S ,4 ( % e s p ) ; \
jne o k ; \
label : \
movl T S S _ s y s e n t e r _ e s p0 + o f f s e t ( % e s p ) ,% e s p ; \
pushfl; \
pushl $ _ _ K E R N E L _ C S ; \
pushl $ s y s e n t e r _ p a s t _ e s p
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KPROBE_ E N T R Y ( d e b u g )
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RING0 _ I N T _ F R A M E
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cmpl $ s y s e n t e r _ e n t r y ,( % e s p )
jne d e b u g _ s t a c k _ c o r r e c t
FIX_ S T A C K ( 1 2 , d e b u g _ s t a c k _ c o r r e c t , d e b u g _ e s p _ f i x _ i n s n )
debug_stack_correct :
pushl $ - 1 # m a r k t h i s a s a n i n t
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CFI_ A D J U S T _ C F A _ O F F S E T 4
2005-04-17 02:20:36 +04:00
SAVE_ A L L
xorl % e d x ,% e d x # e r r o r c o d e 0
movl % e s p ,% e a x # p t _ r e g s p o i n t e r
call d o _ d e b u g
jmp r e t _ f r o m _ e x c e p t i o n
2006-06-26 15:57:44 +04:00
CFI_ E N D P R O C
2005-09-07 02:19:27 +04:00
.previous .text
2005-04-17 02:20:36 +04:00
/ *
* NMI i s d o u b l y n a s t y . I t c a n h a p p e n _ w h i l e _ w e ' r e h a n d l i n g
* a d e b u g f a u l t , a n d t h e d e b u g f a u l t h a s n ' t y e t b e e n a b l e t o
* clear u p t h e s t a c k . S o w e f i r s t c h e c k w h e t h e r w e g o t a n
* NMI o n t h e s y s e n t e r e n t r y p a t h , b u t a f t e r t h a t w e n e e d t o
* check w h e t h e r w e g o t a n N M I o n t h e d e b u g p a t h w h e r e t h e d e b u g
* fault h a p p e n e d o n t h e s y s e n t e r p a t h .
* /
ENTRY( n m i )
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RING0 _ I N T _ F R A M E
2005-04-17 02:20:36 +04:00
pushl % e a x
2006-06-26 15:57:44 +04:00
CFI_ A D J U S T _ C F A _ O F F S E T 4
2005-04-17 02:20:36 +04:00
movl % s s , % e a x
cmpw $ _ _ E S P F I X _ S S , % a x
popl % e a x
2006-06-26 15:57:44 +04:00
CFI_ A D J U S T _ C F A _ O F F S E T - 4
2005-04-17 02:20:36 +04:00
je n m i _ 1 6 b i t _ s t a c k
cmpl $ s y s e n t e r _ e n t r y ,( % e s p )
je n m i _ s t a c k _ f i x u p
pushl % e a x
2006-06-26 15:57:44 +04:00
CFI_ A D J U S T _ C F A _ O F F S E T 4
2005-04-17 02:20:36 +04:00
movl % e s p ,% e a x
/ * Do n o t a c c e s s m e m o r y a b o v e t h e e n d o f o u r s t a c k p a g e ,
* it m i g h t n o t e x i s t .
* /
andl $ ( T H R E A D _ S I Z E - 1 ) ,% e a x
cmpl $ ( T H R E A D _ S I Z E - 2 0 ) ,% e a x
popl % e a x
2006-06-26 15:57:44 +04:00
CFI_ A D J U S T _ C F A _ O F F S E T - 4
2005-04-17 02:20:36 +04:00
jae n m i _ s t a c k _ c o r r e c t
cmpl $ s y s e n t e r _ e n t r y ,1 2 ( % e s p )
je n m i _ d e b u g _ s t a c k _ c h e c k
nmi_stack_correct :
pushl % e a x
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CFI_ A D J U S T _ C F A _ O F F S E T 4
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SAVE_ A L L
xorl % e d x ,% e d x # z e r o e r r o r c o d e
movl % e s p ,% e a x # p t _ r e g s p o i n t e r
call d o _ n m i
jmp r e s t o r e _ a l l
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CFI_ E N D P R O C
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nmi_stack_fixup :
FIX_ S T A C K ( 1 2 ,n m i _ s t a c k _ c o r r e c t , 1 )
jmp n m i _ s t a c k _ c o r r e c t
nmi_debug_stack_check :
cmpw $ _ _ K E R N E L _ C S ,1 6 ( % e s p )
jne n m i _ s t a c k _ c o r r e c t
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cmpl $ d e b u g ,( % e s p )
jb n m i _ s t a c k _ c o r r e c t
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cmpl $ d e b u g _ e s p _ f i x _ i n s n ,( % e s p )
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ja n m i _ s t a c k _ c o r r e c t
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FIX_ S T A C K ( 2 4 ,n m i _ s t a c k _ c o r r e c t , 1 )
jmp n m i _ s t a c k _ c o r r e c t
nmi_16bit_stack :
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RING0 _ I N T _ F R A M E
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/* create the pointer to lss back */
pushl % s s
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CFI_ A D J U S T _ C F A _ O F F S E T 4
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pushl % e s p
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CFI_ A D J U S T _ C F A _ O F F S E T 4
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movzwl % s p , % e s p
addw $ 4 , ( % e s p )
/* copy the iret frame of 12 bytes */
.rept 3
pushl 1 6 ( % e s p )
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CFI_ A D J U S T _ C F A _ O F F S E T 4
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.endr
pushl % e a x
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CFI_ A D J U S T _ C F A _ O F F S E T 4
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SAVE_ A L L
FIXUP_ E S P F I X _ S T A C K # % e a x = = % e s p
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CFI_ A D J U S T _ C F A _ O F F S E T - 2 0 # t h e f r a m e h a s n o w m o v e d
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xorl % e d x ,% e d x # z e r o e r r o r c o d e
call d o _ n m i
RESTORE_ R E G S
lss 1 2 + 4 ( % e s p ) , % e s p # b a c k t o 16 b i t s t a c k
1 : iret
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CFI_ E N D P R O C
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.section _ _ ex_ t a b l e ," a "
.align 4
.long 1 b,i r e t _ e x c
.previous
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KPROBE_ E N T R Y ( i n t 3 )
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RING0 _ I N T _ F R A M E
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pushl $ - 1 # m a r k t h i s a s a n i n t
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CFI_ A D J U S T _ C F A _ O F F S E T 4
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SAVE_ A L L
xorl % e d x ,% e d x # z e r o e r r o r c o d e
movl % e s p ,% e a x # p t _ r e g s p o i n t e r
call d o _ i n t 3
jmp r e t _ f r o m _ e x c e p t i o n
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CFI_ E N D P R O C
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.previous .text
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ENTRY( o v e r f l o w )
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RING0 _ I N T _ F R A M E
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pushl $ 0
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CFI_ A D J U S T _ C F A _ O F F S E T 4
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pushl $ d o _ o v e r f l o w
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CFI_ A D J U S T _ C F A _ O F F S E T 4
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jmp e r r o r _ c o d e
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CFI_ E N D P R O C
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ENTRY( b o u n d s )
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RING0 _ I N T _ F R A M E
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pushl $ 0
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CFI_ A D J U S T _ C F A _ O F F S E T 4
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pushl $ d o _ b o u n d s
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CFI_ A D J U S T _ C F A _ O F F S E T 4
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jmp e r r o r _ c o d e
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CFI_ E N D P R O C
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ENTRY( i n v a l i d _ o p )
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RING0 _ I N T _ F R A M E
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pushl $ 0
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CFI_ A D J U S T _ C F A _ O F F S E T 4
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pushl $ d o _ i n v a l i d _ o p
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CFI_ A D J U S T _ C F A _ O F F S E T 4
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jmp e r r o r _ c o d e
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CFI_ E N D P R O C
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ENTRY( c o p r o c e s s o r _ s e g m e n t _ o v e r r u n )
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RING0 _ I N T _ F R A M E
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pushl $ 0
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CFI_ A D J U S T _ C F A _ O F F S E T 4
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pushl $ d o _ c o p r o c e s s o r _ s e g m e n t _ o v e r r u n
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CFI_ A D J U S T _ C F A _ O F F S E T 4
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jmp e r r o r _ c o d e
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CFI_ E N D P R O C
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ENTRY( i n v a l i d _ T S S )
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RING0 _ E C _ F R A M E
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pushl $ d o _ i n v a l i d _ T S S
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CFI_ A D J U S T _ C F A _ O F F S E T 4
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jmp e r r o r _ c o d e
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CFI_ E N D P R O C
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ENTRY( s e g m e n t _ n o t _ p r e s e n t )
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RING0 _ E C _ F R A M E
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pushl $ d o _ s e g m e n t _ n o t _ p r e s e n t
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CFI_ A D J U S T _ C F A _ O F F S E T 4
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jmp e r r o r _ c o d e
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CFI_ E N D P R O C
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ENTRY( s t a c k _ s e g m e n t )
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RING0 _ E C _ F R A M E
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pushl $ d o _ s t a c k _ s e g m e n t
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CFI_ A D J U S T _ C F A _ O F F S E T 4
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jmp e r r o r _ c o d e
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CFI_ E N D P R O C
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KPROBE_ E N T R Y ( g e n e r a l _ p r o t e c t i o n )
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RING0 _ E C _ F R A M E
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pushl $ d o _ g e n e r a l _ p r o t e c t i o n
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CFI_ A D J U S T _ C F A _ O F F S E T 4
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jmp e r r o r _ c o d e
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CFI_ E N D P R O C
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.previous .text
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ENTRY( a l i g n m e n t _ c h e c k )
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RING0 _ E C _ F R A M E
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pushl $ d o _ a l i g n m e n t _ c h e c k
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CFI_ A D J U S T _ C F A _ O F F S E T 4
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jmp e r r o r _ c o d e
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CFI_ E N D P R O C
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KPROBE_ E N T R Y ( p a g e _ f a u l t )
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RING0 _ E C _ F R A M E
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pushl $ d o _ p a g e _ f a u l t
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CFI_ A D J U S T _ C F A _ O F F S E T 4
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jmp e r r o r _ c o d e
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CFI_ E N D P R O C
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.previous .text
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# ifdef C O N F I G _ X 8 6 _ M C E
ENTRY( m a c h i n e _ c h e c k )
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RING0 _ I N T _ F R A M E
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pushl $ 0
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CFI_ A D J U S T _ C F A _ O F F S E T 4
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pushl m a c h i n e _ c h e c k _ v e c t o r
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CFI_ A D J U S T _ C F A _ O F F S E T 4
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jmp e r r o r _ c o d e
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CFI_ E N D P R O C
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# endif
ENTRY( s p u r i o u s _ i n t e r r u p t _ b u g )
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RING0 _ I N T _ F R A M E
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pushl $ 0
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CFI_ A D J U S T _ C F A _ O F F S E T 4
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pushl $ d o _ s p u r i o u s _ i n t e r r u p t _ b u g
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CFI_ A D J U S T _ C F A _ O F F S E T 4
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jmp e r r o r _ c o d e
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CFI_ E N D P R O C
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# ifdef C O N F I G _ S T A C K _ U N W I N D
ENTRY( a r c h _ u n w i n d _ i n i t _ r u n n i n g )
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CFI_ S T A R T P R O C
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movl 4 ( % e s p ) , % e d x
movl ( % e s p ) , % e c x
leal 4 ( % e s p ) , % e a x
movl % e b x , E B X ( % e d x )
xorl % e b x , % e b x
movl % e b x , E C X ( % e d x )
movl % e b x , E D X ( % e d x )
movl % e s i , E S I ( % e d x )
movl % e d i , E D I ( % e d x )
movl % e b p , E B P ( % e d x )
movl % e b x , E A X ( % e d x )
movl $ _ _ U S E R _ D S , D S ( % e d x )
movl $ _ _ U S E R _ D S , E S ( % e d x )
movl % e b x , O R I G _ E A X ( % e d x )
movl % e c x , E I P ( % e d x )
movl 1 2 ( % e s p ) , % e c x
movl $ _ _ K E R N E L _ C S , C S ( % e d x )
movl % e b x , E F L A G S ( % e d x )
movl % e a x , O L D E S P ( % e d x )
movl 8 ( % e s p ) , % e a x
movl % e c x , 8 ( % e s p )
movl E B X ( % e d x ) , % e b x
movl $ _ _ K E R N E L _ D S , O L D S S ( % e d x )
jmpl * % e a x
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CFI_ E N D P R O C
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ENDPROC( a r c h _ u n w i n d _ i n i t _ r u n n i n g )
# endif
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.section .rodata , " a"
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# include " s y s c a l l _ t a b l e . S "
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syscall_ t a b l e _ s i z e = ( . - s y s _ c a l l _ t a b l e )
