From e780d58fd7b6eda76065327a9921d6157e4a7964 Mon Sep 17 00:00:00 2001 From: Michael Forney Date: Mon, 16 Mar 2020 12:56:56 -0700 Subject: Use breakpad_getcontext on all Linux platforms missing getcontext getcontext is also not available on musl libc, so generalize breakpad_getcontext so it can be used as a fallback for non-Android platforms as well. On x86_64 and i386, ucontext_t uses an Android-specific offset for storage of FP registers, since its sigset_t differs in size. So, make the definition of MCONTEXT_FPREGS_MEM and UCONTEXT_FPREGS_MEM_OFFSET conditional on whether we are building for Android. On glibc and musl, signal.h and asm/sigcontext.h can't be included together, so in breakpad_context_unittest.cc, only compare the libc and kernel _fpstate when on Android. Bug: google-breakpad:631 Change-Id: If81d73c4101bae946e9a3655b8d1c40a34ab6c38 Reviewed-on: https://chromium-review.googlesource.com/c/breakpad/breakpad/+/2102135 Reviewed-by: Mike Frysinger --- src/common/linux/breakpad_getcontext.S | 486 +++++++++++++++++++++++++++++++++ 1 file changed, 486 insertions(+) create mode 100644 src/common/linux/breakpad_getcontext.S (limited to 'src/common/linux/breakpad_getcontext.S') diff --git a/src/common/linux/breakpad_getcontext.S b/src/common/linux/breakpad_getcontext.S new file mode 100644 index 00000000..fea0109d --- /dev/null +++ b/src/common/linux/breakpad_getcontext.S @@ -0,0 +1,486 @@ +// Copyright (c) 2012, Google Inc. +// All rights reserved. +// +// Redistribution and use in source and binary forms, with or without +// modification, are permitted provided that the following conditions are +// met: +// +// * Redistributions of source code must retain the above copyright +// notice, this list of conditions and the following disclaimer. +// * Redistributions in binary form must reproduce the above +// copyright notice, this list of conditions and the following disclaimer +// in the documentation and/or other materials provided with the +// distribution. +// * Neither the name of Google Inc. nor the names of its +// contributors may be used to endorse or promote products derived from +// this software without specific prior written permission. +// +// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS +// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT +// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR +// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT +// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, +// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT +// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, +// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY +// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT +// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE +// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + +// A minimalistic implementation of getcontext() to be used by +// Google Breakpad when getcontext() is not available in libc. + +#include "common/linux/ucontext_constants.h" + +/* int getcontext (ucontext_t *ucp) */ + +#if defined(__arm__) + + .text + .global breakpad_getcontext + .hidden breakpad_getcontext + .type breakpad_getcontext, #function + .align 0 + .fnstart +breakpad_getcontext: + + /* First, save r4-r11 */ + add r1, r0, #(MCONTEXT_GREGS_OFFSET + 4*4) + stm r1, {r4-r11} + + /* r12 is a scratch register, don't save it */ + + /* Save sp and lr explicitly. */ + /* - sp can't be stored with stmia in Thumb-2 */ + /* - STM instructions that store sp and pc are deprecated in ARM */ + str sp, [r0, #(MCONTEXT_GREGS_OFFSET + 13*4)] + str lr, [r0, #(MCONTEXT_GREGS_OFFSET + 14*4)] + + /* Save the caller's address in 'pc' */ + str lr, [r0, #(MCONTEXT_GREGS_OFFSET + 15*4)] + + /* Save ucontext_t* pointer across next call */ + mov r4, r0 + + /* Call sigprocmask(SIG_BLOCK, NULL, &(ucontext->uc_sigmask)) */ + mov r0, #0 /* SIG_BLOCK */ + mov r1, #0 /* NULL */ + add r2, r4, #UCONTEXT_SIGMASK_OFFSET + bl sigprocmask(PLT) + + /* Intentionally do not save the FPU state here. This is because on + * Linux/ARM, one should instead use ptrace(PTRACE_GETFPREGS) or + * ptrace(PTRACE_GETVFPREGS) to get it. + * + * Note that a real implementation of getcontext() would need to save + * this here to allow setcontext()/swapcontext() to work correctly. + */ + + /* Restore the values of r4 and lr */ + mov r0, r4 + ldr lr, [r0, #(MCONTEXT_GREGS_OFFSET + 14*4)] + ldr r4, [r0, #(MCONTEXT_GREGS_OFFSET + 4*4)] + + /* Return 0 */ + mov r0, #0 + bx lr + + .fnend + .size breakpad_getcontext, . - breakpad_getcontext + +#elif defined(__aarch64__) + +#define _NSIG 64 +#define __NR_rt_sigprocmask 135 + + .text + .global breakpad_getcontext + .hidden breakpad_getcontext + .type breakpad_getcontext, #function + .align 4 + .cfi_startproc +breakpad_getcontext: + + /* The saved context will return to the getcontext() call point + with a return value of 0 */ + str xzr, [x0, MCONTEXT_GREGS_OFFSET + 0 * REGISTER_SIZE] + + stp x18, x19, [x0, MCONTEXT_GREGS_OFFSET + 18 * REGISTER_SIZE] + stp x20, x21, [x0, MCONTEXT_GREGS_OFFSET + 20 * REGISTER_SIZE] + stp x22, x23, [x0, MCONTEXT_GREGS_OFFSET + 22 * REGISTER_SIZE] + stp x24, x25, [x0, MCONTEXT_GREGS_OFFSET + 24 * REGISTER_SIZE] + stp x26, x27, [x0, MCONTEXT_GREGS_OFFSET + 26 * REGISTER_SIZE] + stp x28, x29, [x0, MCONTEXT_GREGS_OFFSET + 28 * REGISTER_SIZE] + str x30, [x0, MCONTEXT_GREGS_OFFSET + 30 * REGISTER_SIZE] + + /* Place LR into the saved PC, this will ensure that when + switching to this saved context with setcontext() control + will pass back to the caller of getcontext(), we have + already arranged to return the appropriate return value in x0 + above. */ + str x30, [x0, MCONTEXT_PC_OFFSET] + + /* Save the current SP */ + mov x2, sp + str x2, [x0, MCONTEXT_SP_OFFSET] + + /* Initialize the pstate. */ + str xzr, [x0, MCONTEXT_PSTATE_OFFSET] + + /* Figure out where to place the first context extension + block. */ + add x2, x0, #MCONTEXT_EXTENSION_OFFSET + + /* Write the context extension fpsimd header. */ + mov w3, #(FPSIMD_MAGIC & 0xffff) + movk w3, #(FPSIMD_MAGIC >> 16), lsl #16 + str w3, [x2, #FPSIMD_CONTEXT_MAGIC_OFFSET] + mov w3, #FPSIMD_CONTEXT_SIZE + str w3, [x2, #FPSIMD_CONTEXT_SIZE_OFFSET] + + /* Fill in the FP SIMD context. */ + add x3, x2, #(FPSIMD_CONTEXT_VREGS_OFFSET + 8 * SIMD_REGISTER_SIZE) + stp d8, d9, [x3], #(2 * SIMD_REGISTER_SIZE) + stp d10, d11, [x3], #(2 * SIMD_REGISTER_SIZE) + stp d12, d13, [x3], #(2 * SIMD_REGISTER_SIZE) + stp d14, d15, [x3], #(2 * SIMD_REGISTER_SIZE) + + add x3, x2, FPSIMD_CONTEXT_FPSR_OFFSET + + mrs x4, fpsr + str w4, [x3] + + mrs x4, fpcr + str w4, [x3, FPSIMD_CONTEXT_FPCR_OFFSET - FPSIMD_CONTEXT_FPSR_OFFSET] + + /* Write the termination context extension header. */ + add x2, x2, #FPSIMD_CONTEXT_SIZE + + str xzr, [x2, #FPSIMD_CONTEXT_MAGIC_OFFSET] + str xzr, [x2, #FPSIMD_CONTEXT_SIZE_OFFSET] + + /* Grab the signal mask */ + /* rt_sigprocmask (SIG_BLOCK, NULL, &ucp->uc_sigmask, _NSIG8) */ + add x2, x0, #UCONTEXT_SIGMASK_OFFSET + mov x0, #0 /* SIG_BLOCK */ + mov x1, #0 /* NULL */ + mov x3, #(_NSIG / 8) + mov x8, #__NR_rt_sigprocmask + svc 0 + + /* Return x0 for success */ + mov x0, 0 + ret + + .cfi_endproc + .size breakpad_getcontext, . - breakpad_getcontext + +#elif defined(__i386__) + + .text + .global breakpad_getcontext + .hidden breakpad_getcontext + .align 4 + .type breakpad_getcontext, @function + +breakpad_getcontext: + + movl 4(%esp), %eax /* eax = uc */ + + /* Save register values */ + movl %ecx, MCONTEXT_ECX_OFFSET(%eax) + movl %edx, MCONTEXT_EDX_OFFSET(%eax) + movl %ebx, MCONTEXT_EBX_OFFSET(%eax) + movl %edi, MCONTEXT_EDI_OFFSET(%eax) + movl %esi, MCONTEXT_ESI_OFFSET(%eax) + movl %ebp, MCONTEXT_EBP_OFFSET(%eax) + + movl (%esp), %edx /* return address */ + lea 4(%esp), %ecx /* exclude return address from stack */ + mov %edx, MCONTEXT_EIP_OFFSET(%eax) + mov %ecx, MCONTEXT_ESP_OFFSET(%eax) + + xorl %ecx, %ecx + movw %fs, %cx + mov %ecx, MCONTEXT_FS_OFFSET(%eax) + + movl $0, MCONTEXT_EAX_OFFSET(%eax) + + /* Save floating point state to fpregstate, then update + * the fpregs pointer to point to it */ + leal UCONTEXT_FPREGS_MEM_OFFSET(%eax), %ecx + fnstenv (%ecx) + fldenv (%ecx) + mov %ecx, UCONTEXT_FPREGS_OFFSET(%eax) + + /* Save signal mask: sigprocmask(SIGBLOCK, NULL, &uc->uc_sigmask) */ + leal UCONTEXT_SIGMASK_OFFSET(%eax), %edx + xorl %ecx, %ecx + push %edx /* &uc->uc_sigmask */ + push %ecx /* NULL */ + push %ecx /* SIGBLOCK == 0 on i386 */ + call sigprocmask@PLT + addl $12, %esp + + movl $0, %eax + ret + + .size breakpad_getcontext, . - breakpad_getcontext + +#elif defined(__mips__) + +// This implementation is inspired by implementation of getcontext in glibc. +#include +#include +#if _MIPS_SIM == _ABIO32 +#include +#endif + +// from asm-mips/asm.h +#if _MIPS_SIM == _ABIO32 +#define ALSZ 7 +#define ALMASK ~7 +#define SZREG 4 +#else // _MIPS_SIM != _ABIO32 +#define ALSZ 15 +#define ALMASK ~15 +#define SZREG 8 +#endif + +#include // for __NR_rt_sigprocmask + +#define _NSIG8 128 / 8 +#define SIG_BLOCK 1 + + + .text +LOCALS_NUM = 1 // save gp on stack +FRAME_SIZE = ((LOCALS_NUM * SZREG) + ALSZ) & ALMASK + +GP_FRAME_OFFSET = FRAME_SIZE - (1 * SZREG) +MCONTEXT_REG_SIZE = 8 + +#if _MIPS_SIM == _ABIO32 + +NESTED (breakpad_getcontext, FRAME_SIZE, ra) + .mask 0x00000000, 0 + .fmask 0x00000000, 0 + + .set noreorder + .cpload t9 + .set reorder + + move a2, sp +#define _SP a2 + + addiu sp, -FRAME_SIZE + .cprestore GP_FRAME_OFFSET + + sw s0, (16 * MCONTEXT_REG_SIZE + MCONTEXT_GREGS_OFFSET)(a0) + sw s1, (17 * MCONTEXT_REG_SIZE + MCONTEXT_GREGS_OFFSET)(a0) + sw s2, (18 * MCONTEXT_REG_SIZE + MCONTEXT_GREGS_OFFSET)(a0) + sw s3, (19 * MCONTEXT_REG_SIZE + MCONTEXT_GREGS_OFFSET)(a0) + sw s4, (20 * MCONTEXT_REG_SIZE + MCONTEXT_GREGS_OFFSET)(a0) + sw s5, (21 * MCONTEXT_REG_SIZE + MCONTEXT_GREGS_OFFSET)(a0) + sw s6, (22 * MCONTEXT_REG_SIZE + MCONTEXT_GREGS_OFFSET)(a0) + sw s7, (23 * MCONTEXT_REG_SIZE + MCONTEXT_GREGS_OFFSET)(a0) + sw _SP, (29 * MCONTEXT_REG_SIZE + MCONTEXT_GREGS_OFFSET)(a0) + sw fp, (30 * MCONTEXT_REG_SIZE + MCONTEXT_GREGS_OFFSET)(a0) + sw ra, (31 * MCONTEXT_REG_SIZE + MCONTEXT_GREGS_OFFSET)(a0) + sw ra, MCONTEXT_PC_OFFSET(a0) + +#ifdef __mips_hard_float + s.d fs0, (20 * MCONTEXT_REG_SIZE + MCONTEXT_FPREGS_OFFSET)(a0) + s.d fs1, (22 * MCONTEXT_REG_SIZE + MCONTEXT_FPREGS_OFFSET)(a0) + s.d fs2, (24 * MCONTEXT_REG_SIZE + MCONTEXT_FPREGS_OFFSET)(a0) + s.d fs3, (26 * MCONTEXT_REG_SIZE + MCONTEXT_FPREGS_OFFSET)(a0) + s.d fs4, (28 * MCONTEXT_REG_SIZE + MCONTEXT_FPREGS_OFFSET)(a0) + s.d fs5, (30 * MCONTEXT_REG_SIZE + MCONTEXT_FPREGS_OFFSET)(a0) + + cfc1 v1, fcr31 + sw v1, MCONTEXT_FPC_CSR(a0) +#endif // __mips_hard_float + + /* rt_sigprocmask (SIG_BLOCK, NULL, &ucp->uc_sigmask, _NSIG8) */ + li a3, _NSIG8 + addu a2, a0, UCONTEXT_SIGMASK_OFFSET + move a1, zero + li a0, SIG_BLOCK + li v0, __NR_rt_sigprocmask + syscall + + addiu sp, FRAME_SIZE + jr ra + +END (breakpad_getcontext) +#else + +#ifndef NESTED +/* + * NESTED - declare nested routine entry point + */ +#define NESTED(symbol, framesize, rpc) \ + .globl symbol; \ + .align 2; \ + .type symbol,@function; \ + .ent symbol,0; \ +symbol: .frame sp, framesize, rpc; +#endif + +/* + * END - mark end of function + */ +#ifndef END +# define END(function) \ + .end function; \ + .size function,.-function +#endif + +/* int getcontext (ucontext_t *ucp) */ + +NESTED (breakpad_getcontext, FRAME_SIZE, ra) + .mask 0x10000000, 0 + .fmask 0x00000000, 0 + + move a2, sp +#define _SP a2 + move a3, gp +#define _GP a3 + + daddiu sp, -FRAME_SIZE + .cpsetup $25, GP_FRAME_OFFSET, breakpad_getcontext + + /* Store a magic flag. */ + li v1, 1 + sd v1, (0 * MCONTEXT_REG_SIZE + MCONTEXT_GREGS_OFFSET)(a0) /* zero */ + + sd s0, (16 * MCONTEXT_REG_SIZE + MCONTEXT_GREGS_OFFSET)(a0) + sd s1, (17 * MCONTEXT_REG_SIZE + MCONTEXT_GREGS_OFFSET)(a0) + sd s2, (18 * MCONTEXT_REG_SIZE + MCONTEXT_GREGS_OFFSET)(a0) + sd s3, (19 * MCONTEXT_REG_SIZE + MCONTEXT_GREGS_OFFSET)(a0) + sd s4, (20 * MCONTEXT_REG_SIZE + MCONTEXT_GREGS_OFFSET)(a0) + sd s5, (21 * MCONTEXT_REG_SIZE + MCONTEXT_GREGS_OFFSET)(a0) + sd s6, (22 * MCONTEXT_REG_SIZE + MCONTEXT_GREGS_OFFSET)(a0) + sd s7, (23 * MCONTEXT_REG_SIZE + MCONTEXT_GREGS_OFFSET)(a0) + sd _GP, (28 * MCONTEXT_REG_SIZE + MCONTEXT_GREGS_OFFSET)(a0) + sd _SP, (29 * MCONTEXT_REG_SIZE + MCONTEXT_GREGS_OFFSET)(a0) + sd s8, (30 * MCONTEXT_REG_SIZE + MCONTEXT_GREGS_OFFSET)(a0) + sd ra, (31 * MCONTEXT_REG_SIZE + MCONTEXT_GREGS_OFFSET)(a0) + sd ra, MCONTEXT_PC_OFFSET(a0) + +#ifdef __mips_hard_float + s.d $f24, (24 * MCONTEXT_REG_SIZE + MCONTEXT_FPREGS_OFFSET)(a0) + s.d $f25, (25 * MCONTEXT_REG_SIZE + MCONTEXT_FPREGS_OFFSET)(a0) + s.d $f26, (26 * MCONTEXT_REG_SIZE + MCONTEXT_FPREGS_OFFSET)(a0) + s.d $f27, (27 * MCONTEXT_REG_SIZE + MCONTEXT_FPREGS_OFFSET)(a0) + s.d $f28, (28 * MCONTEXT_REG_SIZE + MCONTEXT_FPREGS_OFFSET)(a0) + s.d $f29, (29 * MCONTEXT_REG_SIZE + MCONTEXT_FPREGS_OFFSET)(a0) + s.d $f30, (30 * MCONTEXT_REG_SIZE + MCONTEXT_FPREGS_OFFSET)(a0) + s.d $f31, (31 * MCONTEXT_REG_SIZE + MCONTEXT_FPREGS_OFFSET)(a0) + + cfc1 v1, $31 + sw v1, MCONTEXT_FPC_CSR(a0) +#endif /* __mips_hard_float */ + +/* rt_sigprocmask (SIG_BLOCK, NULL, &ucp->uc_sigmask, _NSIG8) */ + li a3, _NSIG8 + daddu a2, a0, UCONTEXT_SIGMASK_OFFSET + move a1, zero + li a0, SIG_BLOCK + + li v0, __NR_rt_sigprocmask + syscall + + .cpreturn + daddiu sp, FRAME_SIZE + move v0, zero + jr ra + +END (breakpad_getcontext) +#endif // _MIPS_SIM == _ABIO32 + +#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 + Copyright (C) 2010 Konstantin Belousov + +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!" +#endif -- cgit v1.2.1