A64: Add options for detecting misaligned loads and stores

This commit is contained in:
MerryMage 2020-03-24 21:47:28 +00:00
parent 1ebc1895ee
commit a59c335b05
4 changed files with 100 additions and 7 deletions

View file

@ -170,6 +170,16 @@ struct UserConfig {
/// So there might be wrongly faulted pages which maps to nullptr.
/// This can be avoided by carefully allocating the memory region.
bool absolute_offset_page_table = false;
/// Determines if we should detect memory accesses via page_table that straddle are
/// misaligned. Accesses that straddle page boundaries will fallback to the relevant
/// memory callback.
/// This value should be the required access sizes this applies to ORed together.
/// To detect any access, use: 8 | 16 | 32 | 64 | 128.
std::uint8_t detect_misaligned_access_via_page_table = 0;
/// Determines if the above option only triggers when the misalignment straddles a
/// page boundary.
bool only_detect_misalignment_via_page_table_on_page_boundary = false;
/// This option relates to translation. Generally when we run into an unpredictable
/// instruction the ExceptionRaised callback is called. If this is true, we define

View file

@ -708,14 +708,63 @@ void A64EmitX64::EmitA64SetExclusive(A64EmitContext& ctx, IR::Inst* inst) {
code.mov(qword[r15 + offsetof(A64JitState, exclusive_address)], address);
}
static Xbyak::RegExp EmitVAddrLookup(BlockOfCode& code, A64EmitContext& ctx, Xbyak::Label& abort, Xbyak::Reg64 vaddr, std::optional<Xbyak::Reg64> arg_scratch = {}) {
constexpr size_t page_bits = 12;
constexpr size_t page_size = 1 << page_bits;
namespace {
constexpr size_t page_bits = 12;
constexpr size_t page_size = 1 << page_bits;
void EmitDetectMisaignedVAddr(BlockOfCode& code, A64EmitContext& ctx, size_t bitsize, Xbyak::Label& abort, Xbyak::Reg64 vaddr, Xbyak::Reg64 tmp) {
if (bitsize == 8 || (ctx.conf.detect_misaligned_access_via_page_table & bitsize) == 0) {
return;
}
const u32 align_mask = [bitsize]() -> u32 {
switch (bitsize) {
case 16:
return 0b1;
case 32:
return 0b11;
case 64:
return 0b111;
case 128:
return 0b1111;
}
UNREACHABLE();
}();
code.test(vaddr, align_mask);
if (!ctx.conf.only_detect_misalignment_via_page_table_on_page_boundary) {
code.jnz(abort, code.T_NEAR);
return;
}
const u32 page_align_mask = static_cast<u32>(page_size - 1) & ~align_mask;
Xbyak::Label detect_boundary, resume;
code.jnz(detect_boundary, code.T_NEAR);
code.L(resume);
code.SwitchToFarCode();
code.L(detect_boundary);
code.mov(tmp, vaddr);
code.and_(tmp, page_align_mask);
code.cmp(tmp, page_align_mask);
code.jne(resume, code.T_NEAR);
// NOTE: We expect to fallthrough into abort code here.
code.SwitchToNearCode();
}
Xbyak::RegExp EmitVAddrLookup(BlockOfCode& code, A64EmitContext& ctx, size_t bitsize, Xbyak::Label& abort, Xbyak::Reg64 vaddr, std::optional<Xbyak::Reg64> arg_scratch = {}) {
const size_t valid_page_index_bits = ctx.conf.page_table_address_space_bits - page_bits;
const size_t unused_top_bits = 64 - ctx.conf.page_table_address_space_bits;
const Xbyak::Reg64 page_table = arg_scratch ? *arg_scratch : ctx.reg_alloc.ScratchGpr();
const Xbyak::Reg64 tmp = ctx.reg_alloc.ScratchGpr();
EmitDetectMisaignedVAddr(code, ctx, bitsize, abort, vaddr, tmp);
code.mov(page_table, reinterpret_cast<u64>(ctx.conf.page_table));
code.mov(tmp, vaddr);
if (unused_top_bits == 0) {
@ -745,6 +794,8 @@ static Xbyak::RegExp EmitVAddrLookup(BlockOfCode& code, A64EmitContext& ctx, Xby
return page_table + tmp;
}
} // anonymous namepsace
void A64EmitX64::EmitDirectPageTableMemoryRead(A64EmitContext& ctx, IR::Inst* inst, size_t bitsize) {
Xbyak::Label abort, end;
@ -752,7 +803,7 @@ void A64EmitX64::EmitDirectPageTableMemoryRead(A64EmitContext& ctx, IR::Inst* in
const Xbyak::Reg64 vaddr = ctx.reg_alloc.UseGpr(args[0]);
const Xbyak::Reg64 value = ctx.reg_alloc.ScratchGpr();
auto src_ptr = EmitVAddrLookup(code, ctx, abort, vaddr, value);
const auto src_ptr = EmitVAddrLookup(code, ctx, bitsize, abort, vaddr, value);
switch (bitsize) {
case 8:
code.movzx(value.cvt32(), code.byte[src_ptr]);
@ -785,7 +836,7 @@ void A64EmitX64::EmitDirectPageTableMemoryWrite(A64EmitContext& ctx, IR::Inst* i
const Xbyak::Reg64 vaddr = ctx.reg_alloc.UseGpr(args[0]);
const Xbyak::Reg64 value = ctx.reg_alloc.UseGpr(args[1]);
auto dest_ptr = EmitVAddrLookup(code, ctx, abort, vaddr);
const auto dest_ptr = EmitVAddrLookup(code, ctx, bitsize, abort, vaddr);
switch (bitsize) {
case 8:
code.mov(code.byte[dest_ptr], value.cvt8());
@ -861,7 +912,7 @@ void A64EmitX64::EmitA64ReadMemory128(A64EmitContext& ctx, IR::Inst* inst) {
const Xbyak::Reg64 vaddr = ctx.reg_alloc.UseGpr(args[0]);
const Xbyak::Xmm value = ctx.reg_alloc.ScratchXmm();
const auto src_ptr = EmitVAddrLookup(code, ctx, abort, vaddr);
const auto src_ptr = EmitVAddrLookup(code, ctx, 128, abort, vaddr);
code.movups(value, xword[src_ptr]);
code.L(end);
@ -933,7 +984,7 @@ void A64EmitX64::EmitA64WriteMemory128(A64EmitContext& ctx, IR::Inst* inst) {
const Xbyak::Reg64 vaddr = ctx.reg_alloc.UseGpr(args[0]);
const Xbyak::Xmm value = ctx.reg_alloc.UseXmm(args[1]);
const auto dest_ptr = EmitVAddrLookup(code, ctx, abort, vaddr);
const auto dest_ptr = EmitVAddrLookup(code, ctx, 128, abort, vaddr);
code.movups(xword[dest_ptr], value);
code.L(end);

View file

@ -0,0 +1,31 @@
/* This file is part of the dynarmic project.
* Copyright (c) 2018 MerryMage
* This software may be used and distributed according to the terms of the GNU
* General Public License version 2 or any later version.
*/
#include <catch.hpp>
#include <dynarmic/A64/a64.h>
#include "testenv.h"
TEST_CASE("misaligned load/store do not use page_table when detect_misaligned_access_via_page_table is set", "[a64]") {
A64TestEnv env;
Dynarmic::A64::UserConfig conf{&env};
conf.page_table = nullptr;
conf.detect_misaligned_access_via_page_table = 128;
conf.only_detect_misalignment_via_page_table_on_page_boundary = true;
Dynarmic::A64::Jit jit{conf};
env.code_mem.emplace_back(0x3c800400); // STR Q0, [X0], #0
env.code_mem.emplace_back(0x14000000); // B .
jit.SetPC(0);
jit.SetRegister(0, 0x000000000b0afff8);
env.ticks_left = 2;
jit.Run();
// If we don't crash we're fine.
}

View file

@ -20,6 +20,7 @@ if (DYNARMIC_TESTS_USE_UNICORN)
A32/fuzz_arm.cpp
A32/fuzz_thumb.cpp
A64/fuzz_with_unicorn.cpp
A64/misaligned_page_table.cpp
A64/verify_unicorn.cpp
fuzz_util.cpp
fuzz_util.h