Panda3DS/src/core/loader/elf.cpp
2023-08-13 18:08:22 +03:00

69 lines
No EOL
2.8 KiB
C++

#include "memory.hpp"
#include <cstring>
#include "elfio/elfio.hpp"
using namespace ELFIO;
std::optional<u32> Memory::loadELF(std::ifstream& file) {
loadedCXI = std::nullopt; // ELF files don't have a CXI, so set this to null
elfio reader;
if (!file.good() || !reader.load(file)) {
printf("Woops failed to load ELF\n");
return std::nullopt;
}
// Allocate stack space. For ELFs we use the default stack size, which is 16KB
if (!allocateMainThreadStack(VirtualAddrs::DefaultStackSize)) {
// Should be unreachable
printf("Failed to allocate stack space for ELF file\n");
return std::nullopt;
}
auto segNum = reader.segments.size();
printf("Number of segments: %d\n", segNum);
printf(" # Perms Vaddr File Size Mem Size\n");
for (int i = 0; i < segNum; ++i) {
const auto seg = reader.segments[i];
const auto flags = seg->get_flags();
const u32 vaddr = static_cast<u32>(seg->get_virtual_address()); // Vaddr the segment is loaded in
u32 fileSize = static_cast<u32>(seg->get_file_size()); // Size of segment in file
u32 memorySize = static_cast<u32>(seg->get_memory_size()); // Size of segment in memory
u8* data = (u8*)seg->get_data();
// Get read/write/execute permissions for segment
const bool r = (flags & 0b100) != 0;
const bool w = (flags & 0b010) != 0;
const bool x = (flags & 0b001) != 0;
printf("[%d] (%c%c%c)\t%08X\t%08X\t%08X\n", i, r ? 'r' : '-', w ? 'w' : '-', x ? 'x' : '-', vaddr, fileSize, memorySize);
// Assert that the segment will be loaded in the executable region. If it isn't then panic.
// The executable region starts at 0x00100000 and has a maximum size of 0x03F00000
u64 endAddress = (u64)vaddr + (u64)fileSize;
const bool isGood = vaddr >= VirtualAddrs::ExecutableStart && endAddress < VirtualAddrs::ExecutableEnd;
if (!isGood) {
// We're ignoring this for now because some ELFs define a segment at the vaddr for IPC buffer mapping
// Helpers::panic("ELF is loaded at invalid place");
// return std::nullopt;
}
if (memorySize & pageMask) {
// Round up the size of the ELF segment to a page (4KB) boundary, as the OS can only alloc this way
memorySize = (memorySize + pageSize - 1) & -pageSize;
Helpers::warn("Rounding ELF segment size to %08X\n", memorySize);
}
// This should also assert that findPaddr doesn't fail
u32 fcramAddr = findPaddr(memorySize).value();
std::memcpy(&fcram[fcramAddr], data, fileSize);
// Allocate the segment on the OS side
allocateMemory(vaddr, fcramAddr, memorySize, true, r, w, x);
}
// ELF can't specify a region, make it default to USA
region = Regions::USA;
return static_cast<u32>(reader.get_entry());
}