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3DS: Implement dynamic plugins

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Allows a full build to run on old generation devices
This commit is contained in:
Bastien Bouclet 2019-12-01 17:19:50 +01:00
parent a51c23abd3
commit 34e835a20c
13 changed files with 430 additions and 36 deletions
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34
backends/plugins/elf/arm-loader.cpp
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@ -65,6 +65,7 @@ bool ARMDLObject::relocate(Elf32_Off offset, Elf32_Word size, byte *relSegment)
// Act differently based on the type of relocation
switch (REL_TYPE(rel[i].r_info)) {
case R_ARM_ABS32:
case R_ARM_TARGET1:
if (sym->st_shndx < SHN_LOPROC) { // Only shift for plugin section.
a = *target; // Get full 32 bits of addend
relocation = a + Elf32_Addr(_segment); // Shift by main offset
@ -80,13 +81,36 @@ bool ARMDLObject::relocate(Elf32_Off offset, Elf32_Word size, byte *relSegment)
break;
case R_ARM_CALL:
debug(8, "elfloader: R_ARM_CALL: PC-relative jump, ld takes care of necessary relocation work for us.");
break;
case R_ARM_JUMP24:
debug(8, "elfloader: R_ARM_JUMP24: PC-relative jump, ld takes care of all relocation work for us.");
break;
if (sym->st_shndx == SHN_ABS) { // Absolute symbols used in PC-relative instructions need to be relocated
// Extract the PC offset from the instruction
int32 pcOffset = *target;
pcOffset = (pcOffset & 0x00ffffff) << 2;
if (pcOffset & 0x02000000)
pcOffset -= 0x04000000;
// Shift by the segment offset
pcOffset -= Elf32_Addr(_segment);
// Check the relocated offset is valid for the instruction
if (pcOffset <= (int32)0xfe000000 ||
pcOffset >= (int32)0x02000000) {
warning("elfloader: R_ARM_CALL/R_ARM_JUMP24: Out of range relocation i=%d, target=%p, pcOffset=%d", i, target, pcOffset);
free(rel);
return false;
}
// Put the relocated offset back in the instruction
pcOffset >>= 2;
pcOffset &= 0x00ffffff;
*target &= (uint32)0xff000000;
*target |= (uint32)pcOffset;
debug(8, "elfloader: R_ARM_CALL/R_ARM_JUMP24: i=%d, origTarget=%x, target=%x", i, origTarget, *target);
}
break;
case R_ARM_V4BX:
debug(8, "elfloader: R_ARM_V4BX: No relocation calculation necessary.");
break;