Add x64 version of getcontext.

Assembly code is derived in part from code in libunwind.
Code tested on desktop linux (Android testing pending emulation
support).

BUG=346626
R=dannyb@google.com, thestig@chromium.org

Review URL: https://breakpad.appspot.com/1454002

git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@1311 4c0a9323-5329-0410-9bdc-e9ce6186880e

5 files changed, 275 insertions, 0 deletions

diff --git a/src/common/android/breakpad_getcontext.S b/src/common/android/breakpad_getcontext.S
index 86ef8daf..79fe88df 100644
--- a/src/common/android/breakpad_getcontext.S
+++ b/src/common/android/breakpad_getcontext.S
@@ -305,6 +305,87 @@ NESTED (breakpad_getcontext, FRAME_SIZE, ra)
 
 END (breakpad_getcontext)
 
+#elif defined(__x86_64__)
+/* The x64 implementation of breakpad_getcontext was derived in part
+   from the implementation of libunwind which requires the following
+   notice. */
+/* libunwind - a platform-independent unwind library
+   Copyright (C) 2008 Google, Inc
+	Contributed by Paul Pluzhnikov <ppluzhnikov@google.com>
+   Copyright (C) 2010 Konstantin Belousov <kib@freebsd.org>
+
+This file is part of libunwind.
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+"Software"), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.  */
+
+  .text
+  .global breakpad_getcontext
+  .hidden breakpad_getcontext
+  .align 4
+  .type breakpad_getcontext, @function
+
+breakpad_getcontext:
+  .cfi_startproc
+
+  /* Callee saved: RBX, RBP, R12-R15  */
+  movq %r12, MCONTEXT_GREGS_R12(%rdi)
+  movq %r13, MCONTEXT_GREGS_R13(%rdi)
+  movq %r14, MCONTEXT_GREGS_R14(%rdi)
+  movq %r15, MCONTEXT_GREGS_R15(%rdi)
+  movq %rbp, MCONTEXT_GREGS_RBP(%rdi)
+  movq %rbx, MCONTEXT_GREGS_RBX(%rdi)
+
+  /* Save argument registers (not strictly needed, but setcontext
+     restores them, so don't restore garbage).  */
+  movq %r8,  MCONTEXT_GREGS_R8(%rdi)
+  movq %r9,  MCONTEXT_GREGS_R9(%rdi)
+  movq %rdi, MCONTEXT_GREGS_RDI(%rdi)
+  movq %rsi, MCONTEXT_GREGS_RSI(%rdi)
+  movq %rdx, MCONTEXT_GREGS_RDX(%rdi)
+  movq %rax, MCONTEXT_GREGS_RAX(%rdi)
+  movq %rcx, MCONTEXT_GREGS_RCX(%rdi)
+
+  /* Save fp state (not needed, except for setcontext not
+     restoring garbage).  */
+  leaq MCONTEXT_FPREGS_MEM(%rdi),%r8
+  movq %r8, MCONTEXT_FPREGS_PTR(%rdi)
+  fnstenv (%r8)
+  stmxcsr FPREGS_OFFSET_MXCSR(%r8)
+
+  leaq 8(%rsp), %rax /* exclude this call.  */
+  movq %rax, MCONTEXT_GREGS_RSP(%rdi)
+
+  movq 0(%rsp), %rax
+  movq %rax, MCONTEXT_GREGS_RIP(%rdi)
+
+  /* Save signal mask: sigprocmask(SIGBLOCK, NULL, &uc->uc_sigmask) */
+  leaq UCONTEXT_SIGMASK_OFFSET(%rdi), %rdx  // arg3
+  xorq %rsi, %rsi  // arg2 NULL
+  xorq %rdi, %rdi  // arg1 SIGBLOCK == 0
+  call sigprocmask@PLT
+
+  /* Always return 0 for success, even if sigprocmask failed. */
+  xorl %eax, %eax
+  ret
+  .cfi_endproc
+  .size breakpad_getcontext, . - breakpad_getcontext
 
 #else
 #error "This file has not been ported for your CPU!"
diff --git a/src/common/android/breakpad_getcontext_unittest.cc b/src/common/android/breakpad_getcontext_unittest.cc
index 14d7927a..2c550bf2 100644
--- a/src/common/android/breakpad_getcontext_unittest.cc
+++ b/src/common/android/breakpad_getcontext_unittest.cc
@@ -27,11 +27,26 @@
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
+#if defined(__x86_64__)
+#include <asm/sigcontext.h>
+#endif
+
 #include <sys/ucontext.h>
 
 #include "breakpad_googletest_includes.h"
 #include "common/android/ucontext_constants.h"
 
+template <int left, int right>
+struct CompileAssertEquals {
+  // a compilation error here indicates left and right are not equal.
+  char left_too_large[right - left];
+  // a compilation error here indicates left and right are not equal.
+  char right_too_large[left - right];
+};
+
+#define COMPILE_ASSERT_EQ(left, right, tag) \
+  CompileAssertEquals<left, right> tag;
+
 TEST(AndroidUContext, GRegsOffset) {
 #if defined(__arm__)
   // There is no gregs[] array on ARM, so compare to the offset of
@@ -95,6 +110,70 @@ TEST(AndroidUContext, GRegsOffset) {
 
   ASSERT_EQ(static_cast<size_t>(MCONTEXT_FPC_CSR),
             offsetof(ucontext_t,uc_mcontext.fpc_csr));
+#elif defined(__x86_64__)
+
+  COMPILE_ASSERT_EQ(static_cast<size_t>(MCONTEXT_GREGS_OFFSET),
+                    offsetof(ucontext_t,uc_mcontext.gregs),
+                    mcontext_gregs_offset);
+#define CHECK_REG(x) \
+  COMPILE_ASSERT_EQ(static_cast<size_t>(MCONTEXT_GREGS_##x), \
+                    offsetof(ucontext_t,uc_mcontext.gregs[REG_##x]), reg_##x)
+  CHECK_REG(R8);
+  CHECK_REG(R9);
+  CHECK_REG(R10);
+  CHECK_REG(R11);
+  CHECK_REG(R12);
+  CHECK_REG(R13);
+  CHECK_REG(R14);
+  CHECK_REG(R15);
+  CHECK_REG(RDI);
+  CHECK_REG(RSI);
+  CHECK_REG(RBP);
+  CHECK_REG(RBX);
+  CHECK_REG(RDX);
+  CHECK_REG(RAX);
+  CHECK_REG(RCX);
+  CHECK_REG(RSP);
+  CHECK_REG(RIP);
+
+  // sigcontext is an analog to mcontext_t. The layout should be the same.
+  COMPILE_ASSERT_EQ(offsetof(mcontext_t,fpregs),
+                    offsetof(sigcontext,fpstate), sigcontext_fpstate);
+  // Check that _fpstate from asm/sigcontext.h is essentially the same
+  // as _libc_fpstate.
+  COMPILE_ASSERT_EQ(sizeof(_libc_fpstate), sizeof(_fpstate),
+                    sigcontext_fpstate_size);
+  COMPILE_ASSERT_EQ(offsetof(_libc_fpstate,cwd),offsetof(_fpstate,cwd),
+                    sigcontext_fpstate_cwd);
+  COMPILE_ASSERT_EQ(offsetof(_libc_fpstate,swd),offsetof(_fpstate,swd),
+                    sigcontext_fpstate_swd);
+  COMPILE_ASSERT_EQ(offsetof(_libc_fpstate,ftw),offsetof(_fpstate,twd),
+                    sigcontext_fpstate_twd);
+  COMPILE_ASSERT_EQ(offsetof(_libc_fpstate,fop),offsetof(_fpstate,fop),
+                    sigcontext_fpstate_fop);
+  COMPILE_ASSERT_EQ(offsetof(_libc_fpstate,rip),offsetof(_fpstate,rip),
+                    sigcontext_fpstate_rip);
+  COMPILE_ASSERT_EQ(offsetof(_libc_fpstate,rdp),offsetof(_fpstate,rdp),
+                    sigcontext_fpstate_rdp);
+  COMPILE_ASSERT_EQ(offsetof(_libc_fpstate,mxcsr),offsetof(_fpstate,mxcsr),
+                    sigcontext_fpstate_mxcsr);
+  COMPILE_ASSERT_EQ(offsetof(_libc_fpstate,mxcr_mask),
+                    offsetof(_fpstate,mxcsr_mask),
+                    sigcontext_fpstate_mxcsr_mask);
+  COMPILE_ASSERT_EQ(offsetof(_libc_fpstate,_st), offsetof(_fpstate,st_space),
+                    sigcontext_fpstate_stspace);
+  COMPILE_ASSERT_EQ(offsetof(_libc_fpstate,_xmm), offsetof(_fpstate,xmm_space),
+                    sigcontext_fpstate_xmm_space);
+
+  COMPILE_ASSERT_EQ(MCONTEXT_FPREGS_PTR,
+                    offsetof(ucontext_t,uc_mcontext.fpregs),
+                    mcontext_fpregs_ptr);
+  COMPILE_ASSERT_EQ(MCONTEXT_FPREGS_MEM, offsetof(ucontext_t,__fpregs_mem),
+                    mcontext_fpregs_mem);
+  COMPILE_ASSERT_EQ(FPREGS_OFFSET_MXCSR, offsetof(_libc_fpstate,mxcsr),
+                    fpregs_offset_mxcsr);
+  COMPILE_ASSERT_EQ(UCONTEXT_SIGMASK_OFFSET, offsetof(ucontext_t, uc_sigmask),
+                    ucontext_sigmask);
 #else
   ASSERT_EQ(static_cast<size_t>(MCONTEXT_GREGS_OFFSET),
             offsetof(ucontext_t,uc_mcontext.gregs));
diff --git a/src/common/android/include/sys/ucontext.h b/src/common/android/include/sys/ucontext.h
index bfc22c44..df7019c4 100644
--- a/src/common/android/include/sys/ucontext.h
+++ b/src/common/android/include/sys/ucontext.h
@@ -175,6 +175,73 @@ typedef struct ucontext {
   // Other fields are not used by Google Breakpad. Don't define them.
 } ucontext_t;
 
+#elif defined(__x86_64__)
+enum {
+  REG_R8 = 0,
+  REG_R9,
+  REG_R10,
+  REG_R11,
+  REG_R12,
+  REG_R13,
+  REG_R14,
+  REG_R15,
+  REG_RDI,
+  REG_RSI,
+  REG_RBP,
+  REG_RBX,
+  REG_RDX,
+  REG_RAX,
+  REG_RCX,
+  REG_RSP,
+  REG_RIP,
+  REG_EFL,
+  REG_CSGSFS,
+  REG_ERR,
+  REG_TRAPNO,
+  REG_OLDMASK,
+  REG_CR2,
+  NGREG
+};
+
+// This struct is essentially the same as _fpstate in asm/sigcontext.h
+// except that the individual field names are chosen here to match the
+// ones used in breakpad for other x86_64 platforms.
+struct _libc_fpstate {
+  /* 64-bit FXSAVE format.  */
+  uint16_t cwd;
+  uint16_t swd;
+  uint16_t ftw;
+  uint16_t fop;
+  uint64_t rip;
+  uint64_t rdp;
+  uint32_t mxcsr;
+  uint32_t mxcr_mask;
+  uint32_t _st[32];      // 128 bytes for the ST/MM registers 0-7
+  uint32_t _xmm[64];     // 256 bytes for the XMM registers 0-7
+  uint32_t padding[24];  //  96 bytes
+};
+
+typedef long greg_t;
+typedef greg_t gregset_t[NGREG];
+
+typedef struct _libc_fpstate* fpregset_t;
+
+typedef struct {
+  gregset_t gregs;
+  fpregset_t fpregs;
+  uint64_t __reserved1[8];
+} mcontext_t;
+
+typedef struct ucontext {
+  unsigned long uc_flags;
+  struct ucontext* uc_link;
+  stack_t uc_stack;
+  mcontext_t uc_mcontext;
+  sigset_t uc_sigmask;
+  uint64_t __padding[15];
+  _libc_fpstate __fpregs_mem;
+} ucontext_t;
+
 #else
 #  error "Unsupported Android CPU ABI!"
 #endif
diff --git a/src/common/android/include/sys/user.h b/src/common/android/include/sys/user.h
index 257cd803..7cafd2c9 100644
--- a/src/common/android/include/sys/user.h
+++ b/src/common/android/include/sys/user.h
@@ -143,6 +143,28 @@ struct user_fpregs_struct {
   unsigned int fir;
 };
 
+#elif defined(__x86_64__)
+#include <sys/types.h>
+#include_next <sys/user.h>
+
+// This struct is essentially the same as user_i387_struct in sys/user.h
+// except that the struct name and individual field names are chosen here
+// to match the ones used in breakpad for other x86_64 platforms.
+
+struct user_fpregs_struct {
+  __u16 cwd;
+  __u16 swd;
+  __u16 ftw;
+  __u16 fop;
+  __u64 rip;
+  __u64 rdp;
+  __u32 mxcsr;
+  __u32 mxcr_mask;
+  __u32 st_space[32];   /* 8*16 bytes for each FP-reg = 128 bytes */
+  __u32 xmm_space[64];  /* 16*16 bytes for each XMM-reg = 256 bytes */
+  __u32 padding[24];
+};
+
 #else
 #  error "Unsupported Android CPU ABI"
 #endif
diff --git a/src/common/android/ucontext_constants.h b/src/common/android/ucontext_constants.h
index 251718c3..92871b43 100644
--- a/src/common/android/ucontext_constants.h
+++ b/src/common/android/ucontext_constants.h
@@ -103,6 +103,32 @@
 #define  MCONTEXT_FPC_CSR          556
 #define  UCONTEXT_SIGMASK_OFFSET   616
 
+#elif defined(__x86_64__)
+
+#define MCONTEXT_GREGS_OFFSET     40
+#define UCONTEXT_SIGMASK_OFFSET   296
+
+#define MCONTEXT_GREGS_R8    40
+#define MCONTEXT_GREGS_R9    48
+#define MCONTEXT_GREGS_R10   56
+#define MCONTEXT_GREGS_R11   64
+#define MCONTEXT_GREGS_R12   72
+#define MCONTEXT_GREGS_R13   80
+#define MCONTEXT_GREGS_R14   88
+#define MCONTEXT_GREGS_R15   96
+#define MCONTEXT_GREGS_RDI   104
+#define MCONTEXT_GREGS_RSI   112
+#define MCONTEXT_GREGS_RBP   120
+#define MCONTEXT_GREGS_RBX   128
+#define MCONTEXT_GREGS_RDX   136
+#define MCONTEXT_GREGS_RAX   144
+#define MCONTEXT_GREGS_RCX   152
+#define MCONTEXT_GREGS_RSP   160
+#define MCONTEXT_GREGS_RIP   168
+#define MCONTEXT_FPREGS_PTR  224
+#define MCONTEXT_FPREGS_MEM  424
+#define FPREGS_OFFSET_MXCSR  24
+
 #else
 #error "This header has not been ported for your CPU"
 #endif