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[PATCH] trigger a syntax error if percpu macros are incorrectly used

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get_cpu_var()/per_cpu()/__get_cpu_var() arguments must be simple
identifiers.  Otherwise the arch dependent implementations might break.

This patch enforces the correct usage of the macros by producing a syntax
error if the variable is not a simple identifier.

Signed-off-by: Jan Blunck <jblunck@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Jan Blunck 2006-09-25 23:30:53 -07:00 committed by Linus Torvalds
parent 0a2966b48f
commit 632bbfeee4
4 changed files with 31 additions and 15 deletions
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4
include/asm-generic/percpu.h
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@ -14,7 +14,9 @@ extern unsigned long __per_cpu_offset[NR_CPUS];
__attribute__((__section__(".data.percpu"))) __typeof__(type) per_cpu__##name
/* var is in discarded region: offset to particular copy we want */
#define per_cpu(var, cpu) (*RELOC_HIDE(&per_cpu__##var, __per_cpu_offset[cpu]))
#define per_cpu(var, cpu) (*({ \
extern int simple_indentifier_##var(void); \
RELOC_HIDE(&per_cpu__##var, __per_cpu_offset[cpu]); }))
#define __get_cpu_var(var) per_cpu(var, smp_processor_id())
#define __raw_get_cpu_var(var) per_cpu(var, raw_smp_processor_id())

20
include/asm-s390/percpu.h
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@ -15,18 +15,20 @@
*/
#if defined(__s390x__) && defined(MODULE)
#define __reloc_hide(var,offset) \
(*({ unsigned long *__ptr; \
asm ( "larl %0,per_cpu__"#var"@GOTENT" \
: "=a" (__ptr) : "X" (per_cpu__##var) ); \
(typeof(&per_cpu__##var))((*__ptr) + (offset)); }))
#define __reloc_hide(var,offset) (*({ \
extern int simple_indentifier_##var(void); \
unsigned long *__ptr; \
asm ( "larl %0,per_cpu__"#var"@GOTENT" \
: "=a" (__ptr) : "X" (per_cpu__##var) ); \
(typeof(&per_cpu__##var))((*__ptr) + (offset)); }))
#else
#define __reloc_hide(var, offset) \
(*({ unsigned long __ptr; \
asm ( "" : "=a" (__ptr) : "0" (&per_cpu__##var) ); \
(typeof(&per_cpu__##var)) (__ptr + (offset)); }))
#define __reloc_hide(var, offset) (*({ \
extern int simple_indentifier_##var(void); \
unsigned long __ptr; \
asm ( "" : "=a" (__ptr) : "0" (&per_cpu__##var) ); \
(typeof(&per_cpu__##var)) (__ptr + (offset)); }))
#endif

12
include/asm-x86_64/percpu.h
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@ -21,9 +21,15 @@
__attribute__((__section__(".data.percpu"))) __typeof__(type) per_cpu__##name
/* var is in discarded region: offset to particular copy we want */
#define per_cpu(var, cpu) (*RELOC_HIDE(&per_cpu__##var, __per_cpu_offset(cpu)))
#define __get_cpu_var(var) (*RELOC_HIDE(&per_cpu__##var, __my_cpu_offset()))
#define __raw_get_cpu_var(var) (*RELOC_HIDE(&per_cpu__##var, __my_cpu_offset()))
#define per_cpu(var, cpu) (*({ \
extern int simple_indentifier_##var(void); \
RELOC_HIDE(&per_cpu__##var, __per_cpu_offset(cpu)); }))
#define __get_cpu_var(var) (*({ \
extern int simple_indentifier_##var(void); \
RELOC_HIDE(&per_cpu__##var, __my_cpu_offset()); }))
#define __raw_get_cpu_var(var) (*({ \
extern int simple_indentifier_##var(void); \
RELOC_HIDE(&per_cpu__##var, __my_cpu_offset()); }))
/* A macro to avoid #include hell... */
#define percpu_modcopy(pcpudst, src, size) \

10
include/linux/percpu.h
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@ -11,8 +11,14 @@
#define PERCPU_ENOUGH_ROOM 32768
#endif
/* Must be an lvalue. */
#define get_cpu_var(var) (*({ preempt_disable(); &__get_cpu_var(var); }))
/*
* Must be an lvalue. Since @var must be a simple identifier,
* we force a syntax error here if it isn't.
*/
#define get_cpu_var(var) (*({ \
extern int simple_indentifier_##var(void); \
preempt_disable(); \
&__get_cpu_var(var); }))
#define put_cpu_var(var) preempt_enable()
#ifdef CONFIG_SMP