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 <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>

diff --git a/arch/x86/entry/entry_64_compat.S b/arch/x86/entry/entry_64_compat.S
index 06a8966..75f5fcf 100644 (file)
--- a/arch/x86/entry/entry_64_compat.S
+++ b/arch/x86/entry/entry_64_compat.S
@@ -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 */