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Attempt access on every byte of an unaligned access #23

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Attempt access on every byte of an unaligned access #23

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41 changes: 37 additions & 4 deletions riscv/mmu.h
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Original file line number Diff line number Diff line change
Expand Up @@ -56,8 +56,25 @@ class mmu_t
{
#ifdef RISCV_ENABLE_MISALIGNED
reg_t res = 0;
for (size_t i = 0; i < size; i++)
res += (reg_t)load_uint8(addr + (target_big_endian? size-1-i : i)) << (i * 8);
bool caught_fault = false;
trap_load_access_fault fault(false, 0, 0, 0);
for (size_t i = 0; i < size; i++) {
try {
res += (reg_t)load_uint8(addr + (target_big_endian? size-1-i : i)) << (i * 8);
} catch (trap_load_access_fault& f) {
if (!caught_fault) {
// Catch first fault seen on unaligned access and proceed with other bytes of the access.
fault = f;
caught_fault = true;
}
}
}

if (caught_fault) {
// Throw a fault if we saw onw
throw fault;
}

return res;
#else
bool gva = ((proc) ? proc->state.v : false) || (RISCV_XLATE_VIRT & xlate_flags);
Expand All @@ -68,8 +85,24 @@ class mmu_t
inline void misaligned_store(reg_t addr, reg_t data, size_t size, uint32_t xlate_flags, bool actually_store=true)
{
#ifdef RISCV_ENABLE_MISALIGNED
for (size_t i = 0; i < size; i++)
store_uint8(addr + (target_big_endian? size-1-i : i), data >> (i * 8), actually_store);
bool caught_fault = false;
trap_store_access_fault fault(false, 0, 0, 0);
for (size_t i = 0; i < size; i++) {
try {
store_uint8(addr + (target_big_endian? size-1-i : i), data >> (i * 8), actually_store);
} catch (trap_store_access_fault& f) {
if (!caught_fault) {
// Catch first fault seen on unaligned access and proceed with other bytes of the access.
fault = f;
caught_fault = true;
}
}
}

if (caught_fault) {
// Throw a fault if we saw onw
throw fault;
}
#else
bool gva = ((proc) ? proc->state.v : false) || (RISCV_XLATE_VIRT & xlate_flags);
throw trap_store_address_misaligned(gva, addr, 0, 0);
Expand Down