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x86/entry/64/compat: Remove audit optimizations

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These audit optimizations are messy and hard to maintain.  We'll
get a similar effect from opportunistic sysret when fast compat
system calls are re-implemented.

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Link: http://lkml.kernel.org/r/0bcca79ac7ff835d0e5a38725298865b01347a82.1444091584.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Andy Lutomirski 2015-10-05 17:48:03 -07:00 committed by Ingo Molnar
parent e62a254a1f
commit c5f638ac90
1 changed files with 2 additions and 96 deletions
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98
arch/x86/entry/entry_64_compat.S
View File

@ -16,16 +16,6 @@
#include <linux/linkage.h>
#include <linux/err.h>
/* Avoid __ASSEMBLER__'ifying <linux/audit.h> just for this. */
#include <linux/elf-em.h>
#define AUDIT_ARCH_I386 (EM_386|__AUDIT_ARCH_LE)
#define __AUDIT_ARCH_LE 0x40000000
#ifndef CONFIG_AUDITSYSCALL
# define sysexit_audit ia32_ret_from_sys_call_irqs_off
# define sysretl_audit ia32_ret_from_sys_call_irqs_off
#endif
.section .entry.text, "ax"
#ifdef CONFIG_PARAVIRT
@ -148,7 +138,7 @@ sysenter_dispatch:
DISABLE_INTERRUPTS(CLBR_NONE)
TRACE_IRQS_OFF
testl $_TIF_ALLWORK_MASK, ASM_THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS)
jnz sysexit_audit
jnz ia32_ret_from_sys_call_irqs_off
sysexit_from_sys_call:
/*
* NB: SYSEXIT is not obviously safe for 64-bit kernels -- an
@ -200,81 +190,12 @@ sysexit_from_sys_call:
*/
USERGS_SYSRET32
#ifdef CONFIG_AUDITSYSCALL
.macro auditsys_entry_common
/*
* At this point, registers hold syscall args in the 32-bit syscall ABI:
* EAX is syscall number, the 6 args are in EBX,ECX,EDX,ESI,EDI,EBP.
*
* We want to pass them to __audit_syscall_entry(), which is a 64-bit
* C function with 5 parameters, so shuffle them to match what
* the function expects: RDI,RSI,RDX,RCX,R8.
*/
movl %esi, %r8d /* arg5 (R8 ) <= 4th syscall arg (ESI) */
xchg %ecx, %edx /* arg4 (RCX) <= 3rd syscall arg (EDX) */
/* arg3 (RDX) <= 2nd syscall arg (ECX) */
movl %ebx, %esi /* arg2 (RSI) <= 1st syscall arg (EBX) */
movl %eax, %edi /* arg1 (RDI) <= syscall number (EAX) */
call __audit_syscall_entry
/*
* We are going to jump back to the syscall dispatch code.
* Prepare syscall args as required by the 64-bit C ABI.
* Registers clobbered by __audit_syscall_entry() are
* loaded from pt_regs on stack:
*/
movl ORIG_RAX(%rsp), %eax /* syscall number */
movl %ebx, %edi /* arg1 */
movl RCX(%rsp), %esi /* arg2 */
movl RDX(%rsp), %edx /* arg3 */
movl RSI(%rsp), %ecx /* arg4 */
movl RDI(%rsp), %r8d /* arg5 */
.endm
.macro auditsys_exit exit
TRACE_IRQS_ON
ENABLE_INTERRUPTS(CLBR_NONE)
testl $(_TIF_ALLWORK_MASK & ~_TIF_SYSCALL_AUDIT), ASM_THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS)
jnz ia32_ret_from_sys_call
movl %eax, %esi /* second arg, syscall return value */
cmpl $-MAX_ERRNO, %eax /* is it an error ? */
jbe 1f
movslq %eax, %rsi /* if error sign extend to 64 bits */
1: setbe %al /* 1 if error, 0 if not */
movzbl %al, %edi /* zero-extend that into %edi */
call __audit_syscall_exit
movl $(_TIF_ALLWORK_MASK & ~_TIF_SYSCALL_AUDIT), %edi
DISABLE_INTERRUPTS(CLBR_NONE)
TRACE_IRQS_OFF
testl %edi, ASM_THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS)
jz \exit
xorl %eax, %eax /* Do not leak kernel information */
movq %rax, R11(%rsp)
movq %rax, R10(%rsp)
movq %rax, R9(%rsp)
movq %rax, R8(%rsp)
jmp int_ret_from_sys_call_irqs_off
.endm
sysenter_auditsys:
auditsys_entry_common
movl %ebp, %r9d /* reload 6th syscall arg */
jmp sysenter_dispatch
sysexit_audit:
auditsys_exit sysexit_from_sys_call
#endif
sysenter_fix_flags:
pushq $X86_EFLAGS_FIXED
popfq
jmp sysenter_flags_fixed
sysenter_tracesys:
#ifdef CONFIG_AUDITSYSCALL
testl $(_TIF_WORK_SYSCALL_ENTRY & ~_TIF_SYSCALL_AUDIT), ASM_THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS)
jz sysenter_auditsys
#endif
SAVE_EXTRA_REGS
xorl %eax, %eax /* Do not leak kernel information */
movq %rax, R11(%rsp)
@ -389,7 +310,7 @@ cstar_dispatch:
DISABLE_INTERRUPTS(CLBR_NONE)
TRACE_IRQS_OFF
testl $_TIF_ALLWORK_MASK, ASM_THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS)
jnz sysretl_audit
jnz ia32_ret_from_sys_call_irqs_off
sysretl_from_sys_call:
andl $~TS_COMPAT, ASM_THREAD_INFO(TI_status, %rsp, SIZEOF_PTREGS)
@ -420,22 +341,7 @@ sysretl_from_sys_call:
*/
USERGS_SYSRET32
#ifdef CONFIG_AUDITSYSCALL
cstar_auditsys:
movl %r9d, R9(%rsp) /* register to be clobbered by call */
auditsys_entry_common
movl R9(%rsp), %r9d /* reload 6th syscall arg */
jmp cstar_dispatch
sysretl_audit:
auditsys_exit sysretl_from_sys_call
#endif
cstar_tracesys:
#ifdef CONFIG_AUDITSYSCALL
testl $(_TIF_WORK_SYSCALL_ENTRY & ~_TIF_SYSCALL_AUDIT), ASM_THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS)
jz cstar_auditsys
#endif
xchgl %r9d, %ebp
SAVE_EXTRA_REGS
xorl %eax, %eax /* Do not leak kernel information */