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[LLDB][MIPS] fix Floating point register read/write for big endian
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Reviewers: clayborg, labath, jaydeep

Subscribers: bhushan, slthakur, lldb-commits

Differential Revision: https://reviews.llvm.org/D24603

llvm-svn: 284003
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@jainnk
jainnk committed Oct 12, 2016
1 parent 6b42540 commit 47a2c55
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Showing 5 changed files with 331 additions and 260 deletions.
163 changes: 86 additions & 77 deletions lldb/source/Plugins/Process/Linux/NativeRegisterContextLinux_mips64.cpp
View file
Expand Up @@ -26,6 +26,7 @@
#include "lldb/Core/RegisterValue.h"
#include "lldb/Host/Host.h"
#include "lldb/Host/HostInfo.h"
#include "lldb/Utility/LLDBAssert.h"
#include "lldb/lldb-enumerations.h"
#include "lldb/lldb-private-enumerations.h"
#define NT_MIPS_MSA 0x600
Expand Down Expand Up @@ -392,6 +393,7 @@ NativeRegisterContextLinux_mips64::ReadRegister(const RegisterInfo *reg_info,
}

const uint32_t reg = reg_info->kinds[lldb::eRegisterKindLLDB];
uint8_t byte_size = reg_info->byte_size;
if (reg == LLDB_INVALID_REGNUM) {
// This is likely an internal register for lldb use only and should not be
// directly queried.
Expand All @@ -407,7 +409,8 @@ NativeRegisterContextLinux_mips64::ReadRegister(const RegisterInfo *reg_info,
}

if (IsMSA(reg) || IsFPR(reg)) {
uint8_t *src;
uint8_t *src = nullptr;
lldbassert(reg_info->byte_offset < sizeof(UserArea));

error = ReadCP1();

Expand All @@ -417,14 +420,17 @@ NativeRegisterContextLinux_mips64::ReadRegister(const RegisterInfo *reg_info,
}

if (IsFPR(reg)) {
assert(reg_info->byte_offset < sizeof(UserArea));
src = (uint8_t *)&m_fpr + reg_info->byte_offset - (sizeof(m_gpr));
} else {
assert(reg_info->byte_offset < sizeof(UserArea));
if (IsFR0() && (byte_size != 4)) {
byte_size = 4;
uint8_t ptrace_index;
ptrace_index = reg_info->kinds[lldb::eRegisterKindProcessPlugin];
src = ReturnFPOffset(ptrace_index, reg_info->byte_offset);
} else
src = (uint8_t *)&m_fpr + reg_info->byte_offset - sizeof(m_gpr);
} else
src = (uint8_t *)&m_msa + reg_info->byte_offset -
(sizeof(m_gpr) + sizeof(m_fpr));
}
switch (reg_info->byte_size) {
switch (byte_size) {
case 4:
reg_value.SetUInt32(*(uint32_t *)src);
break;
Expand Down Expand Up @@ -466,21 +472,26 @@ lldb_private::Error NativeRegisterContextLinux_mips64::WriteRegister(
}

if (IsFPR(reg_index) || IsMSA(reg_index)) {
uint8_t *dst;
uint64_t *src;
uint8_t *dst = nullptr;
uint64_t *src = nullptr;
uint8_t byte_size = reg_info->byte_size;
lldbassert(reg_info->byte_offset < sizeof(UserArea));

// Initialise the FP and MSA buffers by reading all co-processor 1 registers
ReadCP1();

if (IsFPR(reg_index)) {
assert(reg_info->byte_offset < sizeof(UserArea));
dst = (uint8_t *)&m_fpr + reg_info->byte_offset - (sizeof(m_gpr));
} else {
assert(reg_info->byte_offset < sizeof(UserArea));
if (IsFR0() && (byte_size != 4)) {
byte_size = 4;
uint8_t ptrace_index;
ptrace_index = reg_info->kinds[lldb::eRegisterKindProcessPlugin];
dst = ReturnFPOffset(ptrace_index, reg_info->byte_offset);
} else
dst = (uint8_t *)&m_fpr + reg_info->byte_offset - sizeof(m_gpr);
} else
dst = (uint8_t *)&m_msa + reg_info->byte_offset -
(sizeof(m_gpr) + sizeof(m_fpr));
}
switch (reg_info->byte_size) {
switch (byte_size) {
case 4:
*(uint32_t *)dst = reg_value.GetAsUInt32();
break;
Expand Down Expand Up @@ -611,11 +622,12 @@ Error NativeRegisterContextLinux_mips64::WriteAllRegisterValues(
Error NativeRegisterContextLinux_mips64::ReadCP1() {
Error error;

uint8_t *src, *dst;
uint8_t *src = nullptr;
uint8_t *dst = nullptr;

lldb::ByteOrder byte_order = GetByteOrder();

uint32_t IsBigEndian = (byte_order == lldb::eByteOrderBig);
bool IsBigEndian = (byte_order == lldb::eByteOrderBig);

if (IsMSAAvailable()) {
error = NativeRegisterContextLinux::ReadRegisterSet(
Expand All @@ -634,42 +646,36 @@ Error NativeRegisterContextLinux_mips64::ReadCP1() {
} else {
error = NativeRegisterContextLinux::ReadFPR();
}
return error;
}

// TODO: Add support for FRE
if (IsFR0()) {
src = (uint8_t *)&m_fpr + 4 + (IsBigEndian * 4);
dst = (uint8_t *)&m_fpr + 8 + (IsBigEndian * 4);
for (int i = 0; i < (NUM_REGISTERS / 2); i++) {
// copy odd single from top of neighbouring even double
*(uint32_t *)dst = *(uint32_t *)src;
src = src + 16;
dst = dst + 16;
}
}
uint8_t *
NativeRegisterContextLinux_mips64::ReturnFPOffset(uint8_t reg_index,
uint32_t byte_offset) {

return error;
uint8_t *fp_buffer_ptr = nullptr;
lldb::ByteOrder byte_order = GetByteOrder();
bool IsBigEndian = (byte_order == lldb::eByteOrderBig);
if (reg_index % 2) {
uint8_t offset_diff = (IsBigEndian) ? 8 : 4;
fp_buffer_ptr =
(uint8_t *)&m_fpr + byte_offset - offset_diff - sizeof(m_gpr);
} else {
fp_buffer_ptr =
(uint8_t *)&m_fpr + byte_offset + 4 * (IsBigEndian) - sizeof(m_gpr);
}
return fp_buffer_ptr;
}

Error NativeRegisterContextLinux_mips64::WriteCP1() {
Error error;

uint8_t *src, *dst;
uint8_t *src = nullptr;
uint8_t *dst = nullptr;

lldb::ByteOrder byte_order = GetByteOrder();

uint32_t IsBigEndian = (byte_order == lldb::eByteOrderBig);

// TODO: Add support for FRE
if (IsFR0()) {
src = (uint8_t *)&m_fpr + 8 + (IsBigEndian * 4);
dst = (uint8_t *)&m_fpr + 4 + (IsBigEndian * 4);
for (int i = 0; i < (NUM_REGISTERS / 2); i++) {
// copy odd single to top of neighbouring even double
*(uint32_t *)dst = *(uint32_t *)src;
src = src + 16;
dst = dst + 16;
}
}
bool IsBigEndian = (byte_order == lldb::eByteOrderBig);

if (IsMSAAvailable()) {
dst = (uint8_t *)&m_msa + (IsBigEndian * 8);
Expand Down Expand Up @@ -1132,50 +1138,53 @@ uint32_t NativeRegisterContextLinux_mips64::NumSupportedHardwareWatchpoints() {
}
return num_valid;
}
Error NativeRegisterContextLinux_mips64::DoReadRegisterValue(
uint32_t offset, const char *reg_name, uint32_t size,
RegisterValue &value) {

Error NativeRegisterContextLinux_mips64::ReadRegisterRaw(uint32_t reg_index,
RegisterValue &value) {
const RegisterInfo *const reg_info = GetRegisterInfoAtIndex(reg_index);

if (!reg_info)
return Error("register %" PRIu32 " not found", reg_index);

uint32_t offset = reg_info->kinds[lldb::eRegisterKindProcessPlugin];

if ((offset == ptrace_sr_mips) || (offset == ptrace_config5_mips))
return Read_SR_Config(reg_info->byte_offset, reg_info->name,
reg_info->byte_size, value);

return DoReadRegisterValue(offset, reg_info->name, reg_info->byte_size,
value);
}

Error NativeRegisterContextLinux_mips64::WriteRegisterRaw(
uint32_t reg_index, const RegisterValue &value) {
const RegisterInfo *const reg_info = GetRegisterInfoAtIndex(reg_index);

if (!reg_info)
return Error("register %" PRIu32 " not found", reg_index);

if (reg_info->invalidate_regs)
lldbassert(false && "reg_info->invalidate_regs is unhandled");

uint32_t offset = reg_info->kinds[lldb::eRegisterKindProcessPlugin];
return DoWriteRegisterValue(offset, reg_info->name, value);
}

Error NativeRegisterContextLinux_mips64::Read_SR_Config(uint32_t offset,
const char *reg_name,
uint32_t size,
RegisterValue &value) {
GPR_linux_mips regs;
::memset(&regs, 0, sizeof(GPR_linux_mips));

// Clear all bits in RegisterValue before writing actual value read from
// ptrace to avoid garbage value in 32-bit MSB
value.SetBytes((void *)(((unsigned char *)&regs) + offset), 8,
GetByteOrder());
Error error = NativeProcessLinux::PtraceWrapper(
PTRACE_GETREGS, m_thread.GetID(), NULL, &regs, sizeof regs);
if (error.Success()) {
lldb_private::ArchSpec arch;
if (m_thread.GetProcess()->GetArchitecture(arch)) {
void *target_address = ((uint8_t *)&regs) + offset +
4 * (arch.GetMachine() == llvm::Triple::mips);
uint32_t target_size;
if ((::strcmp(reg_name, "sr") == 0) ||
(::strcmp(reg_name, "cause") == 0) ||
(::strcmp(reg_name, "config5") == 0))
target_size = 4;
else
target_size =
arch.GetFlags() & lldb_private::ArchSpec::eMIPSABI_O32 ? 4 : 8;
value.SetBytes(target_address, target_size, arch.GetByteOrder());
} else
error.SetErrorString("failed to get architecture");
}
return error;
}

Error NativeRegisterContextLinux_mips64::DoWriteRegisterValue(
uint32_t offset, const char *reg_name, const RegisterValue &value) {
GPR_linux_mips regs;
Error error = NativeProcessLinux::PtraceWrapper(
PTRACE_GETREGS, m_thread.GetID(), NULL, &regs, sizeof regs);
if (error.Success()) {
lldb_private::ArchSpec arch;
if (m_thread.GetProcess()->GetArchitecture(arch)) {
::memcpy((void *)(((unsigned char *)(&regs)) + offset), value.GetBytes(),
arch.GetFlags() & lldb_private::ArchSpec::eMIPSABI_O32 ? 4 : 8);
error = NativeProcessLinux::PtraceWrapper(
PTRACE_SETREGS, m_thread.GetID(), NULL, &regs, sizeof regs);
value.SetUInt(*(uint32_t *)target_address, size);
} else
error.SetErrorString("failed to get architecture");
}
Expand Down
12 changes: 8 additions & 4 deletions lldb/source/Plugins/Process/Linux/NativeRegisterContextLinux_mips64.h
View file
Expand Up @@ -52,6 +52,8 @@ class NativeRegisterContextLinux_mips64 : public NativeRegisterContextLinux {

Error WriteCP1();

uint8_t *ReturnFPOffset(uint8_t reg_index, uint32_t byte_offset);

Error IsWatchpointHit(uint32_t wp_index, bool &is_hit) override;

Error GetWatchpointHitIndex(uint32_t &wp_index,
Expand All @@ -76,11 +78,13 @@ class NativeRegisterContextLinux_mips64 : public NativeRegisterContextLinux {
static bool IsMSAAvailable();

protected:
Error DoReadRegisterValue(uint32_t offset, const char *reg_name,
uint32_t size, RegisterValue &value) override;
Error Read_SR_Config(uint32_t offset, const char *reg_name, uint32_t size,
RegisterValue &value);

Error ReadRegisterRaw(uint32_t reg_index, RegisterValue &value) override;

Error DoWriteRegisterValue(uint32_t offset, const char *reg_name,
const RegisterValue &value) override;
Error WriteRegisterRaw(uint32_t reg_index,
const RegisterValue &value) override;

Error DoReadWatchPointRegisterValue(lldb::tid_t tid, void *watch_readback);

Expand Down

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