diff options
| author | Derek Hensley <hensley.derek58@gmail.com> | 2024-09-03 17:19:13 -0600 |
|---|---|---|
| committer | GitHub <noreply@github.com> | 2024-09-03 19:19:13 -0400 |
| commit | 3e200769f125e2886829dd29a8d786db2406067e (patch) | |
| tree | bf4469bd23a1620ea6deab35445e9dfde8cb5405 /src/code/relocation.c | |
| parent | 2152d1df2d38f71f3693d73a764c981e54031924 (diff) | |
[ntsc-1.2] LoadFragment2 OK (#2118)
* [ntsc-1.2] LoadFragment2 OK
* Add insight about bssSize
Diffstat (limited to 'src/code/relocation.c')
| -rw-r--r-- | src/code/relocation.c | 163 |
1 files changed, 0 insertions, 163 deletions
diff --git a/src/code/relocation.c b/src/code/relocation.c deleted file mode 100644 index eedba8dcd..000000000 --- a/src/code/relocation.c +++ /dev/null @@ -1,163 +0,0 @@ -/** - * @file relocation.c - * - * This file contains the routine responsible for runtime relocation of dynamically loadable code segments (overlays), - * see the description of Overlay_Relocate for details. - * - * @see Overlay_Relocate - */ -#include "global.h" - -// Extract MIPS register rs from an instruction word -#define MIPS_REG_RS(insn) (((insn) >> 0x15) & 0x1F) - -// Extract MIPS register rt from an instruction word -#define MIPS_REG_RT(insn) (((insn) >> 0x10) & 0x1F) - -// Extract MIPS jump target from an instruction word -#define MIPS_JUMP_TARGET(insn) (((insn)&0x03FFFFFF) << 2) - -/** - * Performs runtime relocation of overlay files, loadable code segments. - * - * Overlays are expected to be loadable anywhere in direct-mapped cached (KSEG0) memory, with some appropriate - * alignment requirements; memory addresses in such code must be updated once loaded in order to execute properly. - * When compiled, overlays are given 'fake' KSEG0 RAM addresses larger than the total possible available main memory - * (>= 0x80800000), such addresses are referred to as Virtual RAM (VRAM) to distinguish them. When loading the overlay - * the relocation table produced at compile time is consulted to determine where and how to update these VRAM addresses - * to correct RAM addresses based on the location the overlay was loaded at, enabling the code to execute at this - * address as if it were compiled to run at this address. - * - * Each relocation is represented by a packed 32-bit value, formatted in the following way: - * - [31:30] 2-bit section id, taking values from the `RelocSectionId` enum. - * - [29:24] 6-bit relocation type describing which relocation operation should be performed. Same as ELF32 MIPS. - * - [23: 0] 24-bit section-relative offset indicating where in the section to apply this relocation. - * - * @param allocatedRamAddr Memory address the binary was loaded at. - * @param ovlRelocs Overlay relocation section containing overlay section layout and runtime relocations. - * @param vramStart Virtual RAM address that the overlay was compiled at. - */ -void Overlay_Relocate(void* allocatedRamAddr, OverlayRelocationSection* ovlRelocs, void* vramStart) { - uintptr_t sections[RELOC_SECTION_MAX]; - u32* relocDataP; - u32 reloc; - u32 relocData; - u32 isLoNeg; - uintptr_t allocu32 = (uintptr_t)allocatedRamAddr; - u32 i; - u32* regValP; - //! MIPS ELF relocation does not generally require tracking register values, so at first glance it appears this - //! register tracking was an unnecessary complication. However there is a bug in the IDO compiler that can cause - //! relocations to be emitted in the wrong order under rare circumstances when the compiler attempts to reuse a - //! previous HI16 relocation for a different LO16 relocation as an optimization. This register tracking is likely - //! a workaround to prevent improper matching of unrelated HI16 and LO16 relocations that would otherwise arise - //! due to the incorrect ordering. - u32* luiRefs[32]; - u32 luiVals[32]; - u32* luiInstRef; - u32 dbg; - s32 relocOffset = 0; - u32 relocatedValue = 0; - uintptr_t unrelocatedAddress = 0; - uintptr_t relocatedAddress = 0; - s32 pad; - - if (gOverlayLogSeverity >= 3) { - PRINTF("DoRelocation(%08x, %08x, %08x)\n", allocatedRamAddr, ovlRelocs, vramStart); - PRINTF("text=%08x, data=%08x, rodata=%08x, bss=%08x\n", ovlRelocs->textSize, ovlRelocs->dataSize, - ovlRelocs->rodataSize, ovlRelocs->bssSize); - } - - sections[RELOC_SECTION_NULL] = 0; - sections[RELOC_SECTION_TEXT] = allocu32; - sections[RELOC_SECTION_DATA] = allocu32 + ovlRelocs->textSize; - sections[RELOC_SECTION_RODATA] = sections[RELOC_SECTION_DATA] + ovlRelocs->dataSize; - - for (i = 0; i < ovlRelocs->nRelocations; i++) { - reloc = ovlRelocs->relocations[i]; - // This will always resolve to a 32-bit aligned address as each section containing code or pointers must be - // aligned to at least 4 bytes and the MIPS ABI defines the offset of both 16-bit and 32-bit relocations to - // be the start of the 32-bit word containing the target. - relocDataP = (u32*)(sections[RELOC_SECTION(reloc)] + RELOC_OFFSET(reloc)); - relocData = *relocDataP; - - switch (RELOC_TYPE_MASK(reloc)) { - case R_MIPS_32 << RELOC_TYPE_SHIFT: - // Handles 32-bit address relocation, used for things such as jump tables and pointers in data. - // Just relocate the full address. - - // Check address is valid for relocation - if ((*relocDataP & 0x0F000000) == 0) { - relocOffset = *relocDataP - (uintptr_t)vramStart; - relocatedValue = relocOffset + allocu32; - relocatedAddress = relocatedValue; - unrelocatedAddress = relocData; - *relocDataP = relocatedAddress; - } - break; - - case R_MIPS_26 << RELOC_TYPE_SHIFT: - // Handles 26-bit address relocation, used for jumps and jals. - // Extract the address from the target field of the J-type MIPS instruction. - // Relocate the address and update the instruction. - if (1) { - relocOffset = PHYS_TO_K0(MIPS_JUMP_TARGET(*relocDataP)) - (uintptr_t)vramStart; - unrelocatedAddress = PHYS_TO_K0(MIPS_JUMP_TARGET(*relocDataP)); - relocatedValue = (*relocDataP & 0xFC000000) | (((allocu32 + relocOffset) & 0x0FFFFFFF) >> 2); - relocatedAddress = PHYS_TO_K0(MIPS_JUMP_TARGET(relocatedValue)); - *relocDataP = relocatedValue; - } - break; - - case R_MIPS_HI16 << RELOC_TYPE_SHIFT: - // Handles relocation for a hi/lo pair, part 1. - // Store the reference to the LUI instruction (hi) using the `rt` register of the instruction. - // This will be updated later in the `R_MIPS_LO16` section. - - luiRefs[MIPS_REG_RT(*relocDataP)] = relocDataP; - luiVals[MIPS_REG_RT(*relocDataP)] = *relocDataP; - break; - - case R_MIPS_LO16 << RELOC_TYPE_SHIFT: - // Handles relocation for a hi/lo pair, part 2. - // Grab the stored LUI (hi) from the `R_MIPS_HI16` section using the `rs` register of the instruction. - // The full address is calculated, relocated, and then used to update both the LUI and lo instructions. - // If the lo part is negative, add 1 to the LUI value. - // Note: The lo instruction is assumed to have a signed immediate. - - luiInstRef = luiRefs[MIPS_REG_RS(*relocDataP)]; - regValP = &luiVals[MIPS_REG_RS(*relocDataP)]; - - // Check address is valid for relocation - if ((((*regValP << 0x10) + (s16)*relocDataP) & 0x0F000000) == 0) { - relocOffset = ((*regValP << 0x10) + (s16)*relocDataP) - (uintptr_t)vramStart; - isLoNeg = ((relocOffset + allocu32) & 0x8000) ? 1 : 0; // adjust for signed immediate - unrelocatedAddress = (*luiInstRef << 0x10) + (s16)relocData; - *luiInstRef = - (*luiInstRef & 0xFFFF0000) | ((((relocOffset + allocu32) >> 0x10) & 0xFFFF) + isLoNeg); - relocatedValue = (*relocDataP & 0xFFFF0000) | ((relocOffset + allocu32) & 0xFFFF); - - relocatedAddress = (*luiInstRef << 0x10) + (s16)relocatedValue; - *relocDataP = relocatedValue; - } - break; - } - - dbg = 16; - switch (RELOC_TYPE_MASK(reloc)) { - case R_MIPS_32 << RELOC_TYPE_SHIFT: - dbg += 6; - FALLTHROUGH; - case R_MIPS_26 << RELOC_TYPE_SHIFT: - dbg += 10; - FALLTHROUGH; - case R_MIPS_LO16 << RELOC_TYPE_SHIFT: - if (gOverlayLogSeverity >= 3) { - PRINTF("%02d %08x %08x %08x ", dbg, relocDataP, relocatedValue, relocatedAddress); - PRINTF(" %08x %08x %08x %08x\n", (uintptr_t)relocDataP + (uintptr_t)vramStart - allocu32, relocData, - unrelocatedAddress, relocOffset); - } - // Adding a break prevents matching - } - } -} |
