From: Andy Lutomirski Date: Tue, 6 Oct 2015 00:48:03 +0000 (-0700) Subject: x86/entry/64/compat: Remove audit optimizations X-Git-Url: http://drtracing.org/?a=commitdiff_plain;h=c5f638ac90d514202155c87aa58730e86d484d9e;p=deliverable%2Flinux.git x86/entry/64/compat: Remove audit optimizations 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 Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-kernel@vger.kernel.org Link: http://lkml.kernel.org/r/0bcca79ac7ff835d0e5a38725298865b01347a82.1444091584.git.luto@kernel.org Signed-off-by: Ingo Molnar --- diff --git a/arch/x86/entry/entry_64_compat.S b/arch/x86/entry/entry_64_compat.S index 06a8966415f9..75f5fcf15e11 100644 --- a/arch/x86/entry/entry_64_compat.S +++ b/arch/x86/entry/entry_64_compat.S @@ -16,16 +16,6 @@ #include #include -/* Avoid __ASSEMBLER__'ifying just for this. */ -#include -#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 */