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Code Issues Releases Wiki Activity

GP-4397 Revised ELF R_PPC_ADDR16_LO and R_PPC_ADDR16_HA processing

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ghidra1 2024-03-05 19:26:22 -05:00
parent 711c4de28a
commit 4fb1f03a85
1 changed files with 25 additions and 32 deletions
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57
Ghidra/Processors/PowerPC/src/main/java/ghidra/app/util/bin/format/elf/relocation/PowerPC_ElfRelocationHandler.java
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@ -49,8 +49,8 @@ public class PowerPC_ElfRelocationHandler extends ElfRelocationHandler {
@Override
public RelocationResult relocate(ElfRelocationContext elfRelocationContext,
ElfRelocation relocation,
Address relocationAddress) throws MemoryAccessException, NotFoundException {
ElfRelocation relocation, Address relocationAddress)
throws MemoryAccessException, NotFoundException {
PowerPC_ElfRelocationContext ppcRelocationContext =
(PowerPC_ElfRelocationContext) elfRelocationContext;
@ -100,6 +100,7 @@ public class PowerPC_ElfRelocationHandler extends ElfRelocationHandler {
int symbolValue = (int) elfRelocationContext.getSymbolValue(sym);
// }
String symbolName = elfRelocationContext.getSymbolName(symbolIndex);
long relocbase = elfRelocationContext.getImageBaseWordAdjustmentOffset();
int oldValue = memory.getInt(relocationAddress);
int newValue = 0;
@ -129,7 +130,19 @@ public class PowerPC_ElfRelocationHandler extends ElfRelocationHandler {
break;
case PowerPC_ElfRelocationConstants.R_PPC_ADDR16:
case PowerPC_ElfRelocationConstants.R_PPC_UADDR16:
newValue = symbolValue + addend;
memory.setShort(relocationAddress, (short) newValue);
byteLength = 2;
break;
case PowerPC_ElfRelocationConstants.R_PPC_ADDR16_LO:
if (Long.compareUnsigned(symbolValue, relocbase) > 0 &&
Long.compareUnsigned(symbolValue, relocbase + addend) <= 0) {
/**
* (freebsd) Addend values are sometimes relative to sections in rela,
* where in reality they are relative to relocbase. Detect this condition.
*/
symbolValue = (int) relocbase;
}
newValue = symbolValue + addend;
memory.setShort(relocationAddress, (short) newValue);
byteLength = 2;
@ -139,37 +152,17 @@ public class PowerPC_ElfRelocationHandler extends ElfRelocationHandler {
memory.setShort(relocationAddress, (short) newValue);
byteLength = 2;
break;
/**
*
R_POWERPC_ADDR16_HA: ((Symbol + Addend + 0x8000) >> 16) & 0xffff
static inline void addr16_ha(unsigned char* view, Address value)
{ This::addr16_hi(view, value + 0x8000); }
static inline void
addr16_hi(unsigned char* view, Address value)
{ This::template rela<16,16>(view, 16, 0xffff, value + 0x8000, CHECK_NONE); }
rela(unsigned char* view,
unsigned int right_shift,
typename elfcpp::Valtype_base<fieldsize>::Valtype dst_mask,
Address value,
Overflow_check overflow)
{
typedef typename elfcpp::Swap<fieldsize, big_endian>::Valtype Valtype;
Valtype* wv = reinterpret_cast<Valtype*>(view);
Valtype val = elfcpp::Swap<fieldsize, big_endian>::readval(wv); // original bytes
Valtype reloc = value >> 16;
val &= ~0xffff;
reloc &= dst_mask;
elfcpp::Swap<fieldsize, big_endian>::writeval(wv, val | reloc); // write instr btes
return overflowed<valsize>(value >> 16, overflow);
}
*/
case PowerPC_ElfRelocationConstants.R_PPC_ADDR16_HA:
newValue = (symbolValue + addend + 0x8000) >> 16;
if (Long.compareUnsigned(symbolValue, relocbase) > 0 &&
Long.compareUnsigned(symbolValue, relocbase + addend) <= 0) {
/**
* (freebsd) Addend values are sometimes relative to sections in rela,
* where in reality they are relative to relocbase. Detect this condition.
*/
symbolValue = (int) relocbase;
}
newValue = symbolValue + addend;
newValue = (newValue >> 16) + ((newValue & 0x8000) != 0 ? 1 : 0);
memory.setShort(relocationAddress, (short) newValue);
byteLength = 2;
break;