[compiler-rt] r366225 - [TSan] Improve handling of stack pointer mangling in {set, long}jmp, pt.10

[Julian Lettner via llvm-commits]

Author: yln
Date: Tue Jul 16 09:22:04 2019
New Revision: 366225

URL: http://llvm.org/viewvc/llvm-project?rev=366225&view=rev
Log:
[TSan] Improve handling of stack pointer mangling in {set,long}jmp, pt.10

Remove now-unused assembly code for determining xor key on
Linux/AArch64. This is the final commit of this refactoring.

Modified:
    compiler-rt/trunk/lib/tsan/rtl/tsan_platform_linux.cc
    compiler-rt/trunk/lib/tsan/rtl/tsan_rtl_aarch64.S

Modified: compiler-rt/trunk/lib/tsan/rtl/tsan_platform_linux.cc
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/tsan/rtl/tsan_platform_linux.cc?rev=366225&r1=366224&r2=366225&view=diff
==============================================================================
--- compiler-rt/trunk/lib/tsan/rtl/tsan_platform_linux.cc (original)
+++ compiler-rt/trunk/lib/tsan/rtl/tsan_platform_linux.cc Tue Jul 16 09:22:04 2019
@@ -67,11 +67,6 @@ extern "C" void *__libc_stack_end;
 void *__libc_stack_end = 0;
 #endif
 
-#if SANITIZER_LINUX && defined(__aarch64__)
-__tsan::uptr InitializeGuardPtr() __attribute__((visibility("hidden")));
-extern "C" __tsan::uptr _tsan_pointer_chk_guard;
-#endif
-
 #if SANITIZER_LINUX && defined(__aarch64__) && !SANITIZER_GO
 # define INIT_LONGJMP_XOR_KEY 1
 #else

Modified: compiler-rt/trunk/lib/tsan/rtl/tsan_rtl_aarch64.S
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/tsan/rtl/tsan_rtl_aarch64.S?rev=366225&r1=366224&r2=366225&view=diff
==============================================================================
--- compiler-rt/trunk/lib/tsan/rtl/tsan_rtl_aarch64.S (original)
+++ compiler-rt/trunk/lib/tsan/rtl/tsan_rtl_aarch64.S Tue Jul 16 09:22:04 2019
@@ -3,14 +3,6 @@
 
 #include "sanitizer_common/sanitizer_asm.h"
 
-#if !defined(__APPLE__)
-.section .bss
-.type	__tsan_pointer_chk_guard, %object
-ASM_SIZE(ASM_SYMBOL_INTERCEPTOR(__tsan_pointer_chk_guard))
-__tsan_pointer_chk_guard:
-.zero	8
-#endif
-
 #if defined(__APPLE__)
 .align  2
 
@@ -40,57 +32,6 @@ _sigsetjmp$non_lazy_ptr:
 .align 3
 #endif
 
-#if !defined(__APPLE__)
-// GLIBC mangles the function pointers in jmp_buf (used in {set,long}*jmp
-// functions) by XORing them with a random guard pointer.  For AArch64 it is a
-// global variable rather than a TCB one (as for x86_64/powerpc) and althought
-// its value is exported by the loader, it lies within a private GLIBC
-// namespace (meaning it should be only used by GLIBC itself and the ABI is
-// not stable). So InitializeGuardPtr obtains the pointer guard value by
-// issuing a setjmp and checking the resulting pointers values against the
-// original ones.
-ASM_HIDDEN(_Z18InitializeGuardPtrv)
-.global _Z18InitializeGuardPtrv
-ASM_TYPE_FUNCTION(ASM_SYMBOL_INTERCEPTOR(_Z18InitializeGuardPtrv))
-_Z18InitializeGuardPtrv:
-  CFI_STARTPROC
-  // Allocates a jmp_buf for the setjmp call.
-  stp	x29, x30, [sp, -336]!
-  CFI_DEF_CFA_OFFSET (336)
-  CFI_OFFSET (29, -336)
-  CFI_OFFSET (30, -328)
-  add	x29, sp, 0
-  CFI_DEF_CFA_REGISTER (29)
-  add	x0, x29, 24
-
-  // Call libc setjmp that mangle the stack pointer value
-  adrp  x1, :got:_ZN14__interception12real__setjmpE
-  ldr   x1, [x1, #:got_lo12:_ZN14__interception12real__setjmpE]
-  ldr   x1, [x1]
-  blr   x1
-
-  // glibc setjmp mangles both the frame pointer (FP, pc+4 on blr) and the
-  // stack pointer (SP). FP will be placed on ((uintptr*)jmp_buf)[11] and
-  // SP at ((uintptr*)jmp_buf)[13].
-  // The mangle operation is just 'value' xor 'pointer guard value' and
-  // if we know the original value (SP) and the expected one, we can derive
-  // the guard pointer value.
-  mov	x0, sp
-
-  // Loads the mangled SP pointer.
-  ldr	x1, [x29, 128]
-  eor	x0, x0, x1
-  adrp	x2, __tsan_pointer_chk_guard
-  str	x0, [x2, #:lo12:__tsan_pointer_chk_guard]
-  ldp	x29, x30, [sp], 336
-  CFI_RESTORE (30)
-  CFI_RESTORE (19)
-  CFI_DEF_CFA (31, 0)
-  ret
-  CFI_ENDPROC
-ASM_SIZE(ASM_SYMBOL_INTERCEPTOR(_Z18InitializeGuardPtrv))
-#endif
-
 ASM_HIDDEN(__tsan_setjmp)
 .comm _ZN14__interception11real_setjmpE,8,8
 .globl ASM_SYMBOL_INTERCEPTOR(setjmp)