darlinghq/darling-JavaScriptCore
1
0
Fork 0
mirror of https://github.com/darlinghq/darling-JavaScriptCore.git synced 2025-04-16 05:49:58 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity
darling-JavaScriptCore/assembler/MacroAssemblerARM.cpp
Andrew Hyatt f596e9277a Update JavaScriptCore to 7604.1.38.1.6
2018-01-02 21:17:19 -08:00

371 lines
19 KiB
C++
Raw Blame History

/*
* Copyright (C) 2013-2017 Apple Inc.
* Copyright (C) 2009 University of Szeged
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. 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.
*
* THIS SOFTWARE IS PROVIDED BY UNIVERSITY OF SZEGED ``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 UNIVERSITY OF SZEGED 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.
*/
#include "config.h"
#if ENABLE(ASSEMBLER) && CPU(ARM_TRADITIONAL)
#include "MacroAssembler.h"
#include <wtf/InlineASM.h>
#if OS(LINUX)
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <elf.h>
#include <asm/hwcap.h>
#endif
namespace JSC {
static bool isVFPPresent()
{
#if OS(LINUX)
int fd = open("/proc/self/auxv", O_RDONLY);
if (fd != -1) {
Elf32_auxv_t aux;
while (read(fd, &aux, sizeof(Elf32_auxv_t))) {
if (aux.a_type == AT_HWCAP) {
close(fd);
return aux.a_un.a_val & HWCAP_VFP;
}
}
close(fd);
}
#endif // OS(LINUX)
#if (COMPILER(GCC_OR_CLANG) && defined(__VFP_FP__))
return true;
#else
return false;
#endif
}
const bool MacroAssemblerARM::s_isVFPPresent = isVFPPresent();
#if CPU(ARMV5_OR_LOWER)
/* On ARMv5 and below, natural alignment is required. */
void MacroAssemblerARM::load32WithUnalignedHalfWords(BaseIndex address, RegisterID dest)
{
ARMWord op2;
ASSERT(address.scale >= 0 && address.scale <= 3);
op2 = m_assembler.lsl(address.index, static_cast<int>(address.scale));
if (address.offset >= 0 && address.offset + 0x2 <= 0xff) {
m_assembler.add(ARMRegisters::S0, address.base, op2);
m_assembler.halfDtrUp(ARMAssembler::LoadUint16, dest, ARMRegisters::S0, ARMAssembler::getOp2Half(address.offset));
m_assembler.halfDtrUp(ARMAssembler::LoadUint16, ARMRegisters::S0, ARMRegisters::S0, ARMAssembler::getOp2Half(address.offset + 0x2));
} else if (address.offset < 0 && address.offset >= -0xff) {
m_assembler.add(ARMRegisters::S0, address.base, op2);
m_assembler.halfDtrDown(ARMAssembler::LoadUint16, dest, ARMRegisters::S0, ARMAssembler::getOp2Half(-address.offset));
m_assembler.halfDtrDown(ARMAssembler::LoadUint16, ARMRegisters::S0, ARMRegisters::S0, ARMAssembler::getOp2Half(-address.offset - 0x2));
} else {
m_assembler.moveImm(address.offset, ARMRegisters::S0);
m_assembler.add(ARMRegisters::S0, ARMRegisters::S0, op2);
m_assembler.halfDtrUpRegister(ARMAssembler::LoadUint16, dest, address.base, ARMRegisters::S0);
m_assembler.add(ARMRegisters::S0, ARMRegisters::S0, ARMAssembler::Op2Immediate | 0x2);
m_assembler.halfDtrUpRegister(ARMAssembler::LoadUint16, ARMRegisters::S0, address.base, ARMRegisters::S0);
}
m_assembler.orr(dest, dest, m_assembler.lsl(ARMRegisters::S0, 16));
}
#endif // CPU(ARMV5_OR_LOWER)
#if ENABLE(MASM_PROBE)
extern "C" void ctiMasmProbeTrampoline();
#if COMPILER(GCC_OR_CLANG)
// The following are offsets for ProbeContext fields accessed
// by the ctiMasmProbeTrampoline stub.
#define PTR_SIZE 4
#define PROBE_PROBE_FUNCTION_OFFSET (0 * PTR_SIZE)
#define PROBE_ARG_OFFSET (1 * PTR_SIZE)
#define PROBE_FIRST_GPREG_OFFSET (2 * PTR_SIZE)
#define GPREG_SIZE 4
#define PROBE_CPU_R0_OFFSET (PROBE_FIRST_GPREG_OFFSET + (0 * GPREG_SIZE))
#define PROBE_CPU_R1_OFFSET (PROBE_FIRST_GPREG_OFFSET + (1 * GPREG_SIZE))
#define PROBE_CPU_R2_OFFSET (PROBE_FIRST_GPREG_OFFSET + (2 * GPREG_SIZE))
#define PROBE_CPU_R3_OFFSET (PROBE_FIRST_GPREG_OFFSET + (3 * GPREG_SIZE))
#define PROBE_CPU_R4_OFFSET (PROBE_FIRST_GPREG_OFFSET + (4 * GPREG_SIZE))
#define PROBE_CPU_R5_OFFSET (PROBE_FIRST_GPREG_OFFSET + (5 * GPREG_SIZE))
#define PROBE_CPU_R6_OFFSET (PROBE_FIRST_GPREG_OFFSET + (6 * GPREG_SIZE))
#define PROBE_CPU_R7_OFFSET (PROBE_FIRST_GPREG_OFFSET + (7 * GPREG_SIZE))
#define PROBE_CPU_R8_OFFSET (PROBE_FIRST_GPREG_OFFSET + (8 * GPREG_SIZE))
#define PROBE_CPU_R9_OFFSET (PROBE_FIRST_GPREG_OFFSET + (9 * GPREG_SIZE))
#define PROBE_CPU_R10_OFFSET (PROBE_FIRST_GPREG_OFFSET + (10 * GPREG_SIZE))
#define PROBE_CPU_R11_OFFSET (PROBE_FIRST_GPREG_OFFSET + (11 * GPREG_SIZE))
#define PROBE_CPU_IP_OFFSET (PROBE_FIRST_GPREG_OFFSET + (12 * GPREG_SIZE))
#define PROBE_CPU_SP_OFFSET (PROBE_FIRST_GPREG_OFFSET + (13 * GPREG_SIZE))
#define PROBE_CPU_LR_OFFSET (PROBE_FIRST_GPREG_OFFSET + (14 * GPREG_SIZE))
#define PROBE_CPU_PC_OFFSET (PROBE_FIRST_GPREG_OFFSET + (15 * GPREG_SIZE))
#define PROBE_CPU_APSR_OFFSET (PROBE_FIRST_GPREG_OFFSET + (16 * GPREG_SIZE))
#define PROBE_CPU_FPSCR_OFFSET (PROBE_FIRST_GPREG_OFFSET + (17 * GPREG_SIZE))
#define PROBE_FIRST_FPREG_OFFSET (PROBE_FIRST_GPREG_OFFSET + (18 * GPREG_SIZE))
#define FPREG_SIZE 8
#define PROBE_CPU_D0_OFFSET (PROBE_FIRST_FPREG_OFFSET + (0 * FPREG_SIZE))
#define PROBE_CPU_D1_OFFSET (PROBE_FIRST_FPREG_OFFSET + (1 * FPREG_SIZE))
#define PROBE_CPU_D2_OFFSET (PROBE_FIRST_FPREG_OFFSET + (2 * FPREG_SIZE))
#define PROBE_CPU_D3_OFFSET (PROBE_FIRST_FPREG_OFFSET + (3 * FPREG_SIZE))
#define PROBE_CPU_D4_OFFSET (PROBE_FIRST_FPREG_OFFSET + (4 * FPREG_SIZE))
#define PROBE_CPU_D5_OFFSET (PROBE_FIRST_FPREG_OFFSET + (5 * FPREG_SIZE))
#define PROBE_CPU_D6_OFFSET (PROBE_FIRST_FPREG_OFFSET + (6 * FPREG_SIZE))
#define PROBE_CPU_D7_OFFSET (PROBE_FIRST_FPREG_OFFSET + (7 * FPREG_SIZE))
#define PROBE_CPU_D8_OFFSET (PROBE_FIRST_FPREG_OFFSET + (8 * FPREG_SIZE))
#define PROBE_CPU_D9_OFFSET (PROBE_FIRST_FPREG_OFFSET + (9 * FPREG_SIZE))
#define PROBE_CPU_D10_OFFSET (PROBE_FIRST_FPREG_OFFSET + (10 * FPREG_SIZE))
#define PROBE_CPU_D11_OFFSET (PROBE_FIRST_FPREG_OFFSET + (11 * FPREG_SIZE))
#define PROBE_CPU_D12_OFFSET (PROBE_FIRST_FPREG_OFFSET + (12 * FPREG_SIZE))
#define PROBE_CPU_D13_OFFSET (PROBE_FIRST_FPREG_OFFSET + (13 * FPREG_SIZE))
#define PROBE_CPU_D14_OFFSET (PROBE_FIRST_FPREG_OFFSET + (14 * FPREG_SIZE))
#define PROBE_CPU_D15_OFFSET (PROBE_FIRST_FPREG_OFFSET + (15 * FPREG_SIZE))
#define PROBE_SIZE (PROBE_FIRST_FPREG_OFFSET + (16 * FPREG_SIZE))
#define PROBE_ALIGNED_SIZE (PROBE_SIZE)
// These ASSERTs remind you that if you change the layout of ProbeContext,
// you need to change ctiMasmProbeTrampoline offsets above to match.
#define PROBE_OFFSETOF(x) offsetof(struct ProbeContext, x)
COMPILE_ASSERT(PROBE_OFFSETOF(probeFunction) == PROBE_PROBE_FUNCTION_OFFSET, ProbeContext_probeFunction_offset_matches_ctiMasmProbeTrampoline);
COMPILE_ASSERT(PROBE_OFFSETOF(arg) == PROBE_ARG_OFFSET, ProbeContext_arg_offset_matches_ctiMasmProbeTrampoline);
COMPILE_ASSERT(!(PROBE_CPU_R0_OFFSET & 0x3), ProbeContext_cpu_r0_offset_should_be_4_byte_aligned);
COMPILE_ASSERT(PROBE_OFFSETOF(cpu.r0) == PROBE_CPU_R0_OFFSET, ProbeContext_cpu_r0_offset_matches_ctiMasmProbeTrampoline);
COMPILE_ASSERT(PROBE_OFFSETOF(cpu.r1) == PROBE_CPU_R1_OFFSET, ProbeContext_cpu_r1_offset_matches_ctiMasmProbeTrampoline);
COMPILE_ASSERT(PROBE_OFFSETOF(cpu.r2) == PROBE_CPU_R2_OFFSET, ProbeContext_cpu_r2_offset_matches_ctiMasmProbeTrampoline);
COMPILE_ASSERT(PROBE_OFFSETOF(cpu.r3) == PROBE_CPU_R3_OFFSET, ProbeContext_cpu_r3_offset_matches_ctiMasmProbeTrampoline);
COMPILE_ASSERT(PROBE_OFFSETOF(cpu.r4) == PROBE_CPU_R4_OFFSET, ProbeContext_cpu_r4_offset_matches_ctiMasmProbeTrampoline);
COMPILE_ASSERT(PROBE_OFFSETOF(cpu.r5) == PROBE_CPU_R5_OFFSET, ProbeContext_cpu_r5_offset_matches_ctiMasmProbeTrampoline);
COMPILE_ASSERT(PROBE_OFFSETOF(cpu.r6) == PROBE_CPU_R6_OFFSET, ProbeContext_cpu_r6_offset_matches_ctiMasmProbeTrampoline);
COMPILE_ASSERT(PROBE_OFFSETOF(cpu.r7) == PROBE_CPU_R7_OFFSET, ProbeContext_cpu_r7_offset_matches_ctiMasmProbeTrampoline);
COMPILE_ASSERT(PROBE_OFFSETOF(cpu.r8) == PROBE_CPU_R8_OFFSET, ProbeContext_cpu_r8_offset_matches_ctiMasmProbeTrampoline);
COMPILE_ASSERT(PROBE_OFFSETOF(cpu.r9) == PROBE_CPU_R9_OFFSET, ProbeContext_cpu_r9_offset_matches_ctiMasmProbeTrampoline);
COMPILE_ASSERT(PROBE_OFFSETOF(cpu.r10) == PROBE_CPU_R10_OFFSET, ProbeContext_cpu_r10_offset_matches_ctiMasmProbeTrampoline);
COMPILE_ASSERT(PROBE_OFFSETOF(cpu.r11) == PROBE_CPU_R11_OFFSET, ProbeContext_cpu_r11_offset_matches_ctiMasmProbeTrampoline);
COMPILE_ASSERT(PROBE_OFFSETOF(cpu.ip) == PROBE_CPU_IP_OFFSET, ProbeContext_cpu_ip_offset_matches_ctiMasmProbeTrampoline);
COMPILE_ASSERT(PROBE_OFFSETOF(cpu.sp) == PROBE_CPU_SP_OFFSET, ProbeContext_cpu_sp_offset_matches_ctiMasmProbeTrampoline);
COMPILE_ASSERT(PROBE_OFFSETOF(cpu.lr) == PROBE_CPU_LR_OFFSET, ProbeContext_cpu_lr_offset_matches_ctiMasmProbeTrampoline);
COMPILE_ASSERT(PROBE_OFFSETOF(cpu.pc) == PROBE_CPU_PC_OFFSET, ProbeContext_cpu_pc_offset_matches_ctiMasmProbeTrampoline);
COMPILE_ASSERT(PROBE_OFFSETOF(cpu.apsr) == PROBE_CPU_APSR_OFFSET, ProbeContext_cpu_apsr_offset_matches_ctiMasmProbeTrampoline);
COMPILE_ASSERT(PROBE_OFFSETOF(cpu.fpscr) == PROBE_CPU_FPSCR_OFFSET, ProbeContext_cpu_fpscr_offset_matches_ctiMasmProbeTrampoline);
COMPILE_ASSERT(!(PROBE_CPU_D0_OFFSET & 0xf), ProbeContext_cpu_d0_offset_should_be_16_byte_aligned);
COMPILE_ASSERT(PROBE_OFFSETOF(cpu.d0) == PROBE_CPU_D0_OFFSET, ProbeContext_cpu_d0_offset_matches_ctiMasmProbeTrampoline);
COMPILE_ASSERT(PROBE_OFFSETOF(cpu.d1) == PROBE_CPU_D1_OFFSET, ProbeContext_cpu_d1_offset_matches_ctiMasmProbeTrampoline);
COMPILE_ASSERT(PROBE_OFFSETOF(cpu.d2) == PROBE_CPU_D2_OFFSET, ProbeContext_cpu_d2_offset_matches_ctiMasmProbeTrampoline);
COMPILE_ASSERT(PROBE_OFFSETOF(cpu.d3) == PROBE_CPU_D3_OFFSET, ProbeContext_cpu_d3_offset_matches_ctiMasmProbeTrampoline);
COMPILE_ASSERT(PROBE_OFFSETOF(cpu.d4) == PROBE_CPU_D4_OFFSET, ProbeContext_cpu_d4_offset_matches_ctiMasmProbeTrampoline);
COMPILE_ASSERT(PROBE_OFFSETOF(cpu.d5) == PROBE_CPU_D5_OFFSET, ProbeContext_cpu_d5_offset_matches_ctiMasmProbeTrampoline);
COMPILE_ASSERT(PROBE_OFFSETOF(cpu.d6) == PROBE_CPU_D6_OFFSET, ProbeContext_cpu_d6_offset_matches_ctiMasmProbeTrampoline);
COMPILE_ASSERT(PROBE_OFFSETOF(cpu.d7) == PROBE_CPU_D7_OFFSET, ProbeContext_cpu_d7_offset_matches_ctiMasmProbeTrampoline);
COMPILE_ASSERT(PROBE_OFFSETOF(cpu.d8) == PROBE_CPU_D8_OFFSET, ProbeContext_cpu_d8_offset_matches_ctiMasmProbeTrampoline);
COMPILE_ASSERT(PROBE_OFFSETOF(cpu.d9) == PROBE_CPU_D9_OFFSET, ProbeContext_cpu_d9_offset_matches_ctiMasmProbeTrampoline);
COMPILE_ASSERT(PROBE_OFFSETOF(cpu.d10) == PROBE_CPU_D10_OFFSET, ProbeContext_cpu_d10_offset_matches_ctiMasmProbeTrampoline);
COMPILE_ASSERT(PROBE_OFFSETOF(cpu.d11) == PROBE_CPU_D11_OFFSET, ProbeContext_cpu_d11_offset_matches_ctiMasmProbeTrampoline);
COMPILE_ASSERT(PROBE_OFFSETOF(cpu.d12) == PROBE_CPU_D12_OFFSET, ProbeContext_cpu_d12_offset_matches_ctiMasmProbeTrampoline);
COMPILE_ASSERT(PROBE_OFFSETOF(cpu.d13) == PROBE_CPU_D13_OFFSET, ProbeContext_cpu_d13_offset_matches_ctiMasmProbeTrampoline);
COMPILE_ASSERT(PROBE_OFFSETOF(cpu.d14) == PROBE_CPU_D14_OFFSET, ProbeContext_cpu_d14_offset_matches_ctiMasmProbeTrampoline);
COMPILE_ASSERT(PROBE_OFFSETOF(cpu.d15) == PROBE_CPU_D15_OFFSET, ProbeContext_cpu_d15_offset_matches_ctiMasmProbeTrampoline);
COMPILE_ASSERT(sizeof(ProbeContext) == PROBE_SIZE, ProbeContext_size_matches_ctiMasmProbeTrampoline);
COMPILE_ASSERT(!(PROBE_ALIGNED_SIZE & 0xf), ProbeContext_aligned_size_offset_should_be_16_byte_aligned);
#undef PROBE_OFFSETOF
asm (
".text" "\n"
".globl " SYMBOL_STRING(ctiMasmProbeTrampoline) "\n"
HIDE_SYMBOL(ctiMasmProbeTrampoline) "\n"
INLINE_ARM_FUNCTION(ctiMasmProbeTrampoline) "\n"
SYMBOL_STRING(ctiMasmProbeTrampoline) ":" "\n"
// MacroAssemblerARM::probe() has already generated code to store some values.
// The top of stack now looks like this:
// esp[0 * ptrSize]: probeFunction
// esp[1 * ptrSize]: arg
// esp[2 * ptrSize]: saved r3 / S0
// esp[3 * ptrSize]: saved ip
// esp[4 * ptrSize]: saved lr
// esp[5 * ptrSize]: saved sp
"mov ip, sp" "\n"
"mov r3, sp" "\n"
"sub r3, r3, #" STRINGIZE_VALUE_OF(PROBE_ALIGNED_SIZE) "\n"
// The ARM EABI specifies that the stack needs to be 16 byte aligned.
"bic r3, r3, #0xf" "\n"
"mov sp, r3" "\n"
"str lr, [sp, #" STRINGIZE_VALUE_OF(PROBE_CPU_PC_OFFSET) "]" "\n"
"add lr, sp, #" STRINGIZE_VALUE_OF(PROBE_CPU_R0_OFFSET) "\n"
"stmia lr, { r0-r11 }" "\n"
"mrs lr, APSR" "\n"
"str lr, [sp, #" STRINGIZE_VALUE_OF(PROBE_CPU_APSR_OFFSET) "]" "\n"
"vmrs lr, FPSCR" "\n"
"str lr, [sp, #" STRINGIZE_VALUE_OF(PROBE_CPU_FPSCR_OFFSET) "]" "\n"
"ldr lr, [ip, #0 * " STRINGIZE_VALUE_OF(PTR_SIZE) "]" "\n"
"str lr, [sp, #" STRINGIZE_VALUE_OF(PROBE_PROBE_FUNCTION_OFFSET) "]" "\n"
"ldr lr, [ip, #1 * " STRINGIZE_VALUE_OF(PTR_SIZE) "]" "\n"
"str lr, [sp, #" STRINGIZE_VALUE_OF(PROBE_ARG_OFFSET) "]" "\n"
"ldr lr, [ip, #2 * " STRINGIZE_VALUE_OF(PTR_SIZE) "]" "\n"
"str lr, [sp, #" STRINGIZE_VALUE_OF(PROBE_CPU_R3_OFFSET) "]" "\n"
"ldr lr, [ip, #3 * " STRINGIZE_VALUE_OF(PTR_SIZE) "]" "\n"
"str lr, [sp, #" STRINGIZE_VALUE_OF(PROBE_CPU_IP_OFFSET) "]" "\n"
"ldr lr, [ip, #4 * " STRINGIZE_VALUE_OF(PTR_SIZE) "]" "\n"
"str lr, [sp, #" STRINGIZE_VALUE_OF(PROBE_CPU_LR_OFFSET) "]" "\n"
"ldr lr, [ip, #5 * " STRINGIZE_VALUE_OF(PTR_SIZE) "]" "\n"
"str lr, [sp, #" STRINGIZE_VALUE_OF(PROBE_CPU_SP_OFFSET) "]" "\n"
"ldr lr, [sp, #" STRINGIZE_VALUE_OF(PROBE_CPU_PC_OFFSET) "]" "\n"
"add ip, sp, #" STRINGIZE_VALUE_OF(PROBE_CPU_D0_OFFSET) "\n"
"vstmia.64 ip, { d0-d15 }" "\n"
"mov fp, sp" "\n" // Save the ProbeContext*.
"ldr ip, [sp, #" STRINGIZE_VALUE_OF(PROBE_PROBE_FUNCTION_OFFSET) "]" "\n"
"mov r0, sp" "\n" // the ProbeContext* arg.
"blx ip" "\n"
"mov sp, fp" "\n"
// To enable probes to modify register state, we copy all registers
// out of the ProbeContext before returning.
"add ip, sp, #" STRINGIZE_VALUE_OF(PROBE_CPU_D15_OFFSET + FPREG_SIZE) "\n"
"vldmdb.64 ip!, { d0-d15 }" "\n"
"add ip, sp, #" STRINGIZE_VALUE_OF(PROBE_CPU_R11_OFFSET + GPREG_SIZE) "\n"
"ldmdb ip, { r0-r11 }" "\n"
"ldr ip, [sp, #" STRINGIZE_VALUE_OF(PROBE_CPU_FPSCR_OFFSET) "]" "\n"
"vmsr FPSCR, ip" "\n"
// There are 5 more registers left to restore: ip, sp, lr, pc, and apsr.
// There are 2 issues that complicate the restoration of these last few
// registers:
//
// 1. Normal ARM calling convention relies on moving lr to pc to return to
// the caller. In our case, the address to return to is specified by
// ProbeContext.cpu.pc. And at that moment, we won't have any available
// scratch registers to hold the return address (lr needs to hold
// ProbeContext.cpu.lr, not the return address).
//
// The solution is to store the return address on the stack and load the
// pc from there.
//
// 2. Issue 1 means we will need to write to the stack location at
// ProbeContext.cpu.sp - 4. But if the user probe function had modified
// the value of ProbeContext.cpu.sp to point in the range between
// &ProbeContext.cpu.ip thru &ProbeContext.cpu.aspr, then the action for
// Issue 1 may trash the values to be restored before we can restore
// them.
//
// The solution is to check if ProbeContext.cpu.sp contains a value in
// the undesirable range. If so, we copy the remaining ProbeContext
// register data to a safe range (at memory lower than where
// ProbeContext.cpu.sp points) first, and restore the remaining register
// from this new range.
"add ip, sp, #" STRINGIZE_VALUE_OF(PROBE_CPU_APSR_OFFSET) "\n"
"ldr lr, [sp, #" STRINGIZE_VALUE_OF(PROBE_CPU_SP_OFFSET) "]" "\n"
"cmp lr, ip" "\n"
"bgt " SYMBOL_STRING(ctiMasmProbeTrampolineEnd) "\n"
// We get here because the new expected stack pointer location is lower
// than where it's supposed to be. This means the safe range of stack
// memory where we'll be copying the remaining register restore values to
// might be in a region of memory below the sp i.e. unallocated stack
// memory. This in turn makes it vulnerable to interrupts potentially
// trashing the copied values. To prevent that, we must first allocate the
// needed stack memory by adjusting the sp before the copying.
"sub lr, lr, #(6 * " STRINGIZE_VALUE_OF(PTR_SIZE)
" + " STRINGIZE_VALUE_OF(PROBE_CPU_IP_OFFSET) ")" "\n"
"mov ip, sp" "\n"
"mov sp, lr" "\n"
"mov lr, ip" "\n"
"ldr ip, [lr, #" STRINGIZE_VALUE_OF(PROBE_CPU_IP_OFFSET) "]" "\n"
"str ip, [sp, #" STRINGIZE_VALUE_OF(PROBE_CPU_IP_OFFSET) "]" "\n"
"ldr ip, [lr, #" STRINGIZE_VALUE_OF(PROBE_CPU_SP_OFFSET) "]" "\n"
"str ip, [sp, #" STRINGIZE_VALUE_OF(PROBE_CPU_SP_OFFSET) "]" "\n"
"ldr ip, [lr, #" STRINGIZE_VALUE_OF(PROBE_CPU_LR_OFFSET) "]" "\n"
"str ip, [sp, #" STRINGIZE_VALUE_OF(PROBE_CPU_LR_OFFSET) "]" "\n"
"ldr ip, [lr, #" STRINGIZE_VALUE_OF(PROBE_CPU_PC_OFFSET) "]" "\n"
"str ip, [sp, #" STRINGIZE_VALUE_OF(PROBE_CPU_PC_OFFSET) "]" "\n"
"ldr ip, [lr, #" STRINGIZE_VALUE_OF(PROBE_CPU_APSR_OFFSET) "]" "\n"
"str ip, [sp, #" STRINGIZE_VALUE_OF(PROBE_CPU_APSR_OFFSET) "]" "\n"
SYMBOL_STRING(ctiMasmProbeTrampolineEnd) ":" "\n"
"ldr ip, [sp, #" STRINGIZE_VALUE_OF(PROBE_CPU_PC_OFFSET) "]" "\n"
"ldr lr, [sp, #" STRINGIZE_VALUE_OF(PROBE_CPU_SP_OFFSET) "]" "\n"
"sub lr, lr, #" STRINGIZE_VALUE_OF(PTR_SIZE) "\n"
"str ip, [lr]" "\n"
"str lr, [sp, #" STRINGIZE_VALUE_OF(PROBE_CPU_SP_OFFSET) "]" "\n"
"ldr ip, [sp, #" STRINGIZE_VALUE_OF(PROBE_CPU_APSR_OFFSET) "]" "\n"
"msr APSR, ip" "\n"
"ldr ip, [sp, #" STRINGIZE_VALUE_OF(PROBE_CPU_LR_OFFSET) "]" "\n"
"mov lr, ip" "\n"
"ldr ip, [sp, #" STRINGIZE_VALUE_OF(PROBE_CPU_IP_OFFSET) "]" "\n"
"ldr sp, [sp, #" STRINGIZE_VALUE_OF(PROBE_CPU_SP_OFFSET) "]" "\n"
"pop { pc }" "\n"
);
#endif // COMPILER(GCC_OR_CLANG)
void MacroAssembler::probe(ProbeFunction function, void* arg)
{
push(RegisterID::sp);
push(RegisterID::lr);
push(RegisterID::ip);
push(RegisterID::S0);
// The following uses RegisterID::S0. So, they must come after we push S0 above.
push(trustedImm32FromPtr(arg));
push(trustedImm32FromPtr(function));
move(trustedImm32FromPtr(ctiMasmProbeTrampoline), RegisterID::S0);
m_assembler.blx(RegisterID::S0);
}
#endif // ENABLE(MASM_PROBE)
} // namespace JSC
#endif // ENABLE(ASSEMBLER) && CPU(ARM_TRADITIONAL)
Reference in New Issue View Git Blame Copy Permalink