#silifuzz Make x86 GPR offsets in ucontext_offsets.h relative to GReg…

…Set. This will make splitting of GRegSet from UContext easier. PiperOrigin-RevId: 616181742
google · Mar 15, 2024 · 36757d5 · 36757d5
1 parent 9ae7f8d
commit 36757d5
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Showing 6 changed files with 198 additions and 194 deletions.
diff --git a/third_party/silifuzz_libunwind/restore_ucontext_body.inc b/third_party/silifuzz_libunwind/restore_ucontext_body.inc
@@ -37,9 +37,11 @@ WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.  */
   pushq %rbp
   movq %rsp, %rbp
 
-  /* Save ucontext (%RDI) ptr in %R15 to allow later code use %RDI for
-     syscalls without the need to push/pop every time. */
-  mov %rdi, %r15
+  /* Load GRegSet and FPRegSet pointers into callee save registers so that
+     they are preserved across calls and syscalls below. These will be restored
+     at the exit of this function */
+  leaq UCONTEXT_FPREGS_OFFSET(%rdi), %r14
+  leaq UCONTEXT_GREGS_OFFSET(%rdi), %r15
 
   /*
      if (HasAVX512Registers()) {
@@ -57,21 +59,20 @@ WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.  */
 
   /* Restore fp state. */
   vzeroupper
-  leaq UCONTEXT_FPREGS_OFFSET(%r15), %r8
-  fxrstor64 (%r8) /* Value of r8 must be 16-aligned.
-                     UContext type ensures that. */
-
-  movw UCONTEXT_GREGS_ES_OFFSET(%r15), %es
-  movw UCONTEXT_GREGS_DS_OFFSET(%r15), %ds
-  movw UCONTEXT_GREGS_FS_OFFSET(%r15), %fs
-  movw UCONTEXT_GREGS_GS_OFFSET(%r15), %gs
+  fxrstor64 (%r14) /* Value of r14 must be 16-aligned.
+                      UContext type ensures that. */
+
+  movw GREGS_ES_OFFSET(%r15), %es
+  movw GREGS_DS_OFFSET(%r15), %ds
+  movw GREGS_FS_OFFSET(%r15), %fs
+  movw GREGS_GS_OFFSET(%r15), %gs
   /* We do not restore CS and SS - see comments for SaveUContext()
      and RestoreUContext() in ucontext.h. */
   /* Changing %ss is fraught with danger
      (https://www.felixcloutier.com/x86/mov#operation)
-  movw UCONTEXT_GREGS_SS_OFFSET(%r15), %ss */
+  movw GREGS_SS_OFFSET(%r15), %ss */
   /* %cs cannot be changed with a MOV (causes #UD) https://stackoverflow.com/questions/57314216
-  movw UCONTEXT_GREGS_SS_OFFSET(%r15), %cs */
+  movw GREGS_SS_OFFSET(%r15), %cs */
 
 /* Skip this if we are not allowed to make syscalls */
 #if !defined(UCONTEXT_NO_SYSCALLS)
@@ -83,42 +84,42 @@ WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.  */
      later. */
   mov $__NR_arch_prctl, %rax
   mov $ARCH_SET_FS, %rdi
-  movq UCONTEXT_GREGS_FS_BASE_OFFSET(%r15), %rsi
+  movq GREGS_FS_BASE_OFFSET(%r15), %rsi
   syscall
   mov $__NR_arch_prctl, %rax
   mov $ARCH_SET_GS, %rdi
-  movq UCONTEXT_GREGS_GS_BASE_OFFSET(%r15), %rsi
+  movq GREGS_GS_BASE_OFFSET(%r15), %rsi
   syscall
 #endif /* UCONTEXT_NO_SYSCALLS */
 
   /* Restore bulk of the registers. */
-  movq UCONTEXT_GREGS_R8_OFFSET(%r15),%r8
-  movq UCONTEXT_GREGS_R9_OFFSET(%r15),%r9
-  movq UCONTEXT_GREGS_R10_OFFSET(%r15),%r10
-  movq UCONTEXT_GREGS_R11_OFFSET(%r15),%r11
-  movq UCONTEXT_GREGS_RBX_OFFSET(%r15),%rbx
-  movq UCONTEXT_GREGS_RBP_OFFSET(%r15),%rbp
-  movq UCONTEXT_GREGS_R12_OFFSET(%r15),%r12
-  movq UCONTEXT_GREGS_R13_OFFSET(%r15),%r13
-  movq UCONTEXT_GREGS_R14_OFFSET(%r15),%r14
-  movq UCONTEXT_GREGS_RSI_OFFSET(%r15),%rsi
-  movq UCONTEXT_GREGS_RDI_OFFSET(%r15),%rdi
-  movq UCONTEXT_GREGS_RDX_OFFSET(%r15),%rdx
-  movq UCONTEXT_GREGS_RAX_OFFSET(%r15),%rax
-  movq UCONTEXT_GREGS_RSP_OFFSET(%r15),%rsp
+  movq GREGS_R8_OFFSET(%r15),%r8
+  movq GREGS_R9_OFFSET(%r15),%r9
+  movq GREGS_R10_OFFSET(%r15),%r10
+  movq GREGS_R11_OFFSET(%r15),%r11
+  movq GREGS_RBX_OFFSET(%r15),%rbx
+  movq GREGS_RBP_OFFSET(%r15),%rbp
+  movq GREGS_R12_OFFSET(%r15),%r12
+  movq GREGS_R13_OFFSET(%r15),%r13
+  movq GREGS_R14_OFFSET(%r15),%r14
+  movq GREGS_RSI_OFFSET(%r15),%rsi
+  movq GREGS_RDI_OFFSET(%r15),%rdi
+  movq GREGS_RDX_OFFSET(%r15),%rdx
+  movq GREGS_RAX_OFFSET(%r15),%rax
+  movq GREGS_RSP_OFFSET(%r15),%rsp
 
   /* Push the return address on the restored stack for below retq to use. */
-  movq UCONTEXT_GREGS_RIP_OFFSET(%r15),%rcx
+  movq GREGS_RIP_OFFSET(%r15),%rcx
   pushq %rcx
 
   /* Restore rcx. */
-  movq UCONTEXT_GREGS_RCX_OFFSET(%r15),%rcx
+  movq GREGS_RCX_OFFSET(%r15),%rcx
 
   /* Push eflags on the restored stack for popfq below to use. */
-  pushq UCONTEXT_GREGS_EFLAGS_OFFSET(%r15)
+  pushq GREGS_EFLAGS_OFFSET(%r15)
 
   /* Restore r15. */
-  movq UCONTEXT_GREGS_R15_OFFSET(%r15),%r15
+  movq GREGS_R15_OFFSET(%r15),%r15
 
   /* Restore eflags. */
   popfq

diff --git a/third_party/silifuzz_libunwind/save_ucontext_body.inc b/third_party/silifuzz_libunwind/save_ucontext_body.inc
@@ -36,48 +36,47 @@ WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.  */
   pushq %rbp
   movq %rsp, %rbp
 
-  /* Save eflags. */
+  /* Save eflags and %r15 and also load GRegSet base to callee-saved register
+     %r15 so that it is preserved across calls and syscalls below. */
   pushfq
-  popq UCONTEXT_GREGS_EFLAGS_OFFSET(%rdi)
-
-  /* Save %R15 in ucontext. Then copy ucontext (%RDI) ptr in %R15 to allow
-    later code use %RDI for syscalls without the need to push/pop every time. */
-  movq %r15, UCONTEXT_GREGS_R15_OFFSET(%rdi)
-  mov %rdi, %r15
+  pushq %r15
+  leaq UCONTEXT_GREGS_OFFSET(%rdi), %r15
+  popq GREGS_R15_OFFSET(%r15)
+  popq GREGS_EFLAGS_OFFSET(%r15)
 
   /* Callee saved registers %rbx, %r12-%14. */
-  movq %r12, UCONTEXT_GREGS_R12_OFFSET(%r15)
-  movq %r13, UCONTEXT_GREGS_R13_OFFSET(%r15)
-  movq %r14, UCONTEXT_GREGS_R14_OFFSET(%r15)
-  movq %rbx, UCONTEXT_GREGS_RBX_OFFSET(%r15)
+  movq %r12, GREGS_R12_OFFSET(%r15)
+  movq %r13, GREGS_R13_OFFSET(%r15)
+  movq %r14, GREGS_R14_OFFSET(%r15)
+  movq %rbx, GREGS_RBX_OFFSET(%r15)
 
   /* Save argument registers. */
-  movq %r8,  UCONTEXT_GREGS_R8_OFFSET(%r15)
-  movq %r9,  UCONTEXT_GREGS_R9_OFFSET(%r15)
-  movq %r10, UCONTEXT_GREGS_R10_OFFSET(%r15)
-  movq %r11, UCONTEXT_GREGS_R11_OFFSET(%r15)
-  movq %rdi, UCONTEXT_GREGS_RDI_OFFSET(%r15)
-  movq %rsi, UCONTEXT_GREGS_RSI_OFFSET(%r15)
-  movq %rdx, UCONTEXT_GREGS_RDX_OFFSET(%r15)
-  movq %rax, UCONTEXT_GREGS_RAX_OFFSET(%r15)
-  movq %rcx, UCONTEXT_GREGS_RCX_OFFSET(%r15)
-
-/* We want to save %rsp of the caller before the call instead of the current
+  movq %r8,  GREGS_R8_OFFSET(%r15)
+  movq %r9,  GREGS_R9_OFFSET(%r15)
+  movq %r10, GREGS_R10_OFFSET(%r15)
+  movq %r11, GREGS_R11_OFFSET(%r15)
+  movq %rdi, GREGS_RDI_OFFSET(%r15)
+  movq %rsi, GREGS_RSI_OFFSET(%r15)
+  movq %rdx, GREGS_RDX_OFFSET(%r15)
+  movq %rax, GREGS_RAX_OFFSET(%r15)
+  movq %rcx, GREGS_RCX_OFFSET(%r15)
+
+  /* We want to save %rsp of the caller before the call instead of the current
    value. We can derived it from the frame pointer. */
   leaq 0x10(%rbp), %rax
-  movq %rax, UCONTEXT_GREGS_RSP_OFFSET(%r15)
+  movq %rax, GREGS_RSP_OFFSET(%r15)
 
   /* Similarly, save %rbp of the caller. */
   movq (%rbp), %rax
-  movq %rax, UCONTEXT_GREGS_RBP_OFFSET(%r15)
+  movq %rax, GREGS_RBP_OFFSET(%r15)
 
   /* Save segment registers. */
-  movw %cs, UCONTEXT_GREGS_CS_OFFSET(%r15)
-  movw %gs, UCONTEXT_GREGS_GS_OFFSET(%r15)
-  movw %fs, UCONTEXT_GREGS_FS_OFFSET(%r15)
-  movw %ss, UCONTEXT_GREGS_SS_OFFSET(%r15)
-  movw %ds, UCONTEXT_GREGS_DS_OFFSET(%r15)
-  movw %es, UCONTEXT_GREGS_ES_OFFSET(%r15)
+  movw %cs, GREGS_CS_OFFSET(%r15)
+  movw %gs, GREGS_GS_OFFSET(%r15)
+  movw %fs, GREGS_FS_OFFSET(%r15)
+  movw %ss, GREGS_SS_OFFSET(%r15)
+  movw %ds, GREGS_DS_OFFSET(%r15)
+  movw %es, GREGS_ES_OFFSET(%r15)
 
   /* Skip this if we are not allowed to make syscalls */
 #if !defined(UCONTEXT_NO_SYSCALLS)
@@ -89,26 +88,26 @@ WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.  */
      get restored later. */
   mov $__NR_arch_prctl, %rax
   mov $ARCH_GET_FS, %rdi
-  leaq UCONTEXT_GREGS_FS_BASE_OFFSET(%r15), %rsi
+  leaq GREGS_FS_BASE_OFFSET(%r15), %rsi
   syscall
   mov $__NR_arch_prctl, %rax
   mov $ARCH_GET_GS, %rdi
-  leaq UCONTEXT_GREGS_GS_BASE_OFFSET(%r15), %rsi
+  leaq GREGS_GS_BASE_OFFSET(%r15), %rsi
   syscall
 #else
   /* Make sure fs_base and gs_base are initialized. */
-  movq $0, UCONTEXT_GREGS_FS_BASE_OFFSET(%r15)
-  movq $0, UCONTEXT_GREGS_GS_BASE_OFFSET(%r15)
+  movq $0, GREGS_FS_BASE_OFFSET(%r15)
+  movq $0, GREGS_GS_BASE_OFFSET(%r15)
 #endif
 
   /* Save fp state. */
-  leaq UCONTEXT_FPREGS_OFFSET(%r15), %r8
-  fxsave64 (%r8) /* Value of r8 must be 16-aligned.
-                    UContext type ensures that */
+  movq GREGS_RDI_OFFSET(%r15), %rdi
+  fxsave64 UCONTEXT_FPREGS_OFFSET(%rdi) /* Address must be 16-aligned.
+                                           UContext type ensures that */
 
   /* Save %rip. It is the PC value after call instruction in caller. */
   movq 8(%rbp), %rax
-  movq %rax, UCONTEXT_GREGS_RIP_OFFSET(%r15)
+  movq %rax, GREGS_RIP_OFFSET(%r15)
 
   /* Restore all argument registers.
      Some we have clobbered above; some might have been clobbered in syscall.
@@ -117,19 +116,17 @@ WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.  */
      registers do not change), but doing the restore makes the definition,
      behavior, and testing of SaveUContext() and RestoreUContext() simpler
      and more aligned. */
-  movq UCONTEXT_GREGS_R8_OFFSET(%r15), %r8
-  movq UCONTEXT_GREGS_R9_OFFSET(%r15), %r9
-  movq UCONTEXT_GREGS_R10_OFFSET(%r15), %r10
-  movq UCONTEXT_GREGS_R11_OFFSET(%r15), %r11
-  movq UCONTEXT_GREGS_RSI_OFFSET(%r15), %rsi
-  movq UCONTEXT_GREGS_RDX_OFFSET(%r15), %rdx
-  movq UCONTEXT_GREGS_RAX_OFFSET(%r15), %rax
-  movq UCONTEXT_GREGS_RCX_OFFSET(%r15), %rcx
-  mov %r15, %rdi
-  movq UCONTEXT_GREGS_R15_OFFSET(%r15), %r15
-
-  /* Restore eflags. */
-  pushq UCONTEXT_GREGS_EFLAGS_OFFSET(%rdi)
+  movq GREGS_R8_OFFSET(%r15), %r8
+  movq GREGS_R9_OFFSET(%r15), %r9
+  movq GREGS_R10_OFFSET(%r15), %r10
+  movq GREGS_R11_OFFSET(%r15), %r11
+  movq GREGS_RSI_OFFSET(%r15), %rsi
+  movq GREGS_RDX_OFFSET(%r15), %rdx
+  movq GREGS_RAX_OFFSET(%r15), %rax
+  movq GREGS_RCX_OFFSET(%r15), %rcx
+  movq GREGS_RDI_OFFSET(%r15), %rdi
+  pushq GREGS_EFLAGS_OFFSET(%r15)
+  movq GREGS_R15_OFFSET(%r15), %r15
   popfq
 
   /* Instructions in the epilogue must not change %rflags. */

diff --git a/util/ucontext/BUILD b/util/ucontext/BUILD
@@ -328,5 +328,8 @@ cc_test(
 cc_binary(
     name = "ucontext_offsets_gen",
     srcs = ["x86_64/ucontext_offsets_gen.cc"],
-    deps = [":ucontext_types"],
+    deps = [
+        ":ucontext_types",
+        "@silifuzz//util:arch",
+    ],
 )
diff --git a/util/ucontext/x86_64/ucontext_offsets.h b/util/ucontext/x86_64/ucontext_offsets.h
@@ -1,4 +1,4 @@
-// Copyright 2022 The SiliFuzz Authors.
+// Copyright 2024 The SiliFuzz Authors.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
@@ -16,30 +16,31 @@
 #ifndef THIRD_PARTY_SILIFUZZ_UTIL_UCONTEXT_X86_64_UCONTEXT_OFFSETS_H_
 #define THIRD_PARTY_SILIFUZZ_UTIL_UCONTEXT_X86_64_UCONTEXT_OFFSETS_H_
 #define UCONTEXT_FPREGS_OFFSET 0x0
-#define UCONTEXT_GREGS_R8_OFFSET 0x200
-#define UCONTEXT_GREGS_R9_OFFSET 0x208
-#define UCONTEXT_GREGS_R10_OFFSET 0x210
-#define UCONTEXT_GREGS_R11_OFFSET 0x218
-#define UCONTEXT_GREGS_R12_OFFSET 0x220
-#define UCONTEXT_GREGS_R13_OFFSET 0x228
-#define UCONTEXT_GREGS_R14_OFFSET 0x230
-#define UCONTEXT_GREGS_R15_OFFSET 0x238
-#define UCONTEXT_GREGS_RAX_OFFSET 0x268
-#define UCONTEXT_GREGS_RBX_OFFSET 0x258
-#define UCONTEXT_GREGS_RCX_OFFSET 0x270
-#define UCONTEXT_GREGS_RDX_OFFSET 0x260
-#define UCONTEXT_GREGS_RBP_OFFSET 0x250
-#define UCONTEXT_GREGS_RSP_OFFSET 0x278
-#define UCONTEXT_GREGS_RSI_OFFSET 0x248
-#define UCONTEXT_GREGS_RDI_OFFSET 0x240
-#define UCONTEXT_GREGS_RIP_OFFSET 0x280
-#define UCONTEXT_GREGS_EFLAGS_OFFSET 0x288
-#define UCONTEXT_GREGS_FS_BASE_OFFSET 0x2a0
-#define UCONTEXT_GREGS_GS_BASE_OFFSET 0x2a8
-#define UCONTEXT_GREGS_CS_OFFSET 0x290
-#define UCONTEXT_GREGS_SS_OFFSET 0x296
-#define UCONTEXT_GREGS_FS_OFFSET 0x294
-#define UCONTEXT_GREGS_GS_OFFSET 0x292
-#define UCONTEXT_GREGS_ES_OFFSET 0x29a
-#define UCONTEXT_GREGS_DS_OFFSET 0x298
+#define UCONTEXT_GREGS_OFFSET 0x200
+#define GREGS_R8_OFFSET 0x0
+#define GREGS_R9_OFFSET 0x8
+#define GREGS_R10_OFFSET 0x10
+#define GREGS_R11_OFFSET 0x18
+#define GREGS_R12_OFFSET 0x20
+#define GREGS_R13_OFFSET 0x28
+#define GREGS_R14_OFFSET 0x30
+#define GREGS_R15_OFFSET 0x38
+#define GREGS_RAX_OFFSET 0x68
+#define GREGS_RBX_OFFSET 0x58
+#define GREGS_RCX_OFFSET 0x70
+#define GREGS_RDX_OFFSET 0x60
+#define GREGS_RBP_OFFSET 0x50
+#define GREGS_RSP_OFFSET 0x78
+#define GREGS_RSI_OFFSET 0x48
+#define GREGS_RDI_OFFSET 0x40
+#define GREGS_RIP_OFFSET 0x80
+#define GREGS_EFLAGS_OFFSET 0x88
+#define GREGS_FS_BASE_OFFSET 0xa0
+#define GREGS_GS_BASE_OFFSET 0xa8
+#define GREGS_CS_OFFSET 0x90
+#define GREGS_SS_OFFSET 0x96
+#define GREGS_FS_OFFSET 0x94
+#define GREGS_GS_OFFSET 0x92
+#define GREGS_ES_OFFSET 0x9a
+#define GREGS_DS_OFFSET 0x98
 #endif  // THIRD_PARTY_SILIFUZZ_UTIL_UCONTEXT_X86_64_UCONTEXT_OFFSETS_H_