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Core/Boot: Fix ELF load address semantics

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Tested with a binary that has VMA != (LMA | 0x80000000), unlike most
libogc binaries.  This is indeed a valid setup for ELFs, and one that is
generally expected to work properly.

Test code: https://github.com/Wii-Linux/NPLL/tree/reloc

In either case, you still need to set the PC in the debugger to get it
to boot properly, though that is a different issue that I will be fixing
in a future patch.
Without this patch, the code to be runtime-relocated ends up already
loaded at the desired final address, and then when the code tries to
relocate from what it thinks is the source address (where the code
should be, where the LMA is) to the destination address (the VMA, where
Dolphin mistakenly already put the code), it ends up overwriting the
code that it is about to execute with garbage, and then promptly
crashing.
After this patch is applied, the behavior now matches the GameCube with
Swiss (assuming a [recent patch](bb4a57186c)
is applied), and the Wii with the Homebrew Channel.
This commit is contained in:
techflashYT 2025-11-12 21:21:51 -07:00
parent 0c349306e3
commit b2a57f4391
1 changed files with 10 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

14
Source/Core/Core/Boot/ElfReader.cpp
View File

@ -143,17 +143,23 @@ bool ElfReader::LoadIntoMemory(Core::System& system, bool only_in_mem1) const
{
Elf32_Phdr* p = segments + i;
INFO_LOG_FMT(BOOT, "Type: {} Vaddr: {:08x} Filesz: {} Memsz: {}", p->p_type, p->p_vaddr,
p->p_filesz, p->p_memsz);
INFO_LOG_FMT(BOOT, "Type: {} Vaddr: {:08x} Paddr: {:08x} Filesz: {} Memsz: {}", p->p_type,
p->p_vaddr, p->p_paddr, p->p_filesz, p->p_memsz);
if (p->p_type == PT_LOAD)
{
u32 writeAddr = p->p_vaddr;
// Check LMA (paddr) first - some are nonsense, so fall back to VMA (vaddr) if invalid
u32 writeAddr = p->p_paddr;
if (writeAddr)
writeAddr |= 0x80000000; // map to virtual address
else
writeAddr = p->p_vaddr; // LMA is empty, fall back to VMA
const u8* src = GetSegmentPtr(i);
u32 srcSize = p->p_filesz;
u32 dstSize = p->p_memsz;
if (only_in_mem1 && p->p_vaddr >= memory.GetRamSizeReal())
if (only_in_mem1 && writeAddr >= memory.GetRamSizeReal())
continue;
memory.CopyToEmu(writeAddr, src, srcSize);