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Experiment with supporting Windows Arm64 natively

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So far I haven't found any way to run native Arm64 code on Windows Arm64
without using MSVC. When I build a PE binary from scratch that should be
a valid Windows Arm64 program, the OS refuses to run it. Possibly due to
requiring additional content like XML manifests or relocation or control
flow integrity data that isn't normally required on x64. I've also tried
using VirtualAlloc2() to JIT an Arm64 native function, but VirtualAlloc2
always fails with invalid parameter. I tried using MSVC to create an ARM
DLL that my x64 emulated program can link at runtime, to pass a function
pointer with ARM code, but LoadLibrary() rejects ARM DLLs as invalid exe

The only option left, is likely to write a new program like ape/ape-m1.c
which can be compiled by MSVC to load and run an AARCH64 ELF executable.
The emulated x64 binary would detect emulation using IsWow64Process2 and
then drop the loader executable in a temporary folder, and re-launch the
original executable, using the Arm64 segments of the cosmocc fat binary.
This commit is contained in:
Justine Tunney 2024-08-16 06:43:59 -07:00
parent 1671283f1a
commit 5bd22aef12
No known key found for this signature in database
GPG key ID: BE714B4575D6E328
12 changed files with 88 additions and 16 deletions
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29
tool/build/elf2pe.c
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@ -229,6 +229,17 @@ static struct Segment *NewSegment(void) {
return s;
}
static int ConvertElfMachineToPe(struct Elf *elf) {
switch (elf->ehdr->e_machine) {
case EM_NEXGEN32E:
return kNtImageFileMachineNexgen32e;
case EM_AARCH64:
return kNtImageFileMachineArm64;
default:
Die(elf->path, "unsupported e_machine");
}
}
static Elf64_Addr RelocateVaddrWithinSegment(struct Elf *elf,
Elf64_Addr vaddr_old,
struct Segment *segment) {
@ -811,7 +822,17 @@ static uint32_t GetPeSectionCharacteristics(struct Segment *s) {
// originally in the elf image that ld linked. in order for this to work
// the executable needs to be linked in `ld -q` mode, since it'll retain
// the .rela sections we'll need later to fixup the binary.
static struct ImagePointer GeneratePe(struct Elf *elf, char *fp, int64_t vp) {
static struct ImagePointer GeneratePe(struct Elf *elf, char *fp) {
int64_t vp = 0;
Elf64_Phdr *phdr;
for (int i = 0; i < elf->ehdr->e_phnum; ++i) {
if ((phdr = GetElfProgramHeaderAddress(elf->ehdr, elf->size, i)) &&
phdr->p_type == PT_LOAD) {
vp = phdr->p_vaddr;
break;
}
}
Elf64_Sym *entry;
if (!(entry = FindGlobal(elf, "__win32_start")) &&
@ -855,7 +876,7 @@ static struct ImagePointer GeneratePe(struct Elf *elf, char *fp, int64_t vp) {
struct NtImageFileHeader *filehdr;
filehdr = (struct NtImageFileHeader *)fp;
fp += sizeof(struct NtImageFileHeader);
filehdr->Machine = kNtImageFileMachineNexgen32e;
filehdr->Machine = ConvertElfMachineToPe(elf);
filehdr->TimeDateStamp = 1690072024;
filehdr->Characteristics =
kNtPeFileExecutableImage | kNtImageFileLargeAddressAware |
@ -873,7 +894,9 @@ static struct ImagePointer GeneratePe(struct Elf *elf, char *fp, int64_t vp) {
opthdr->FileAlignment = 512;
opthdr->SectionAlignment = MAX(4096, elf->align);
opthdr->MajorOperatingSystemVersion = 6;
opthdr->MinorOperatingSystemVersion = 2;
opthdr->MajorSubsystemVersion = 6;
opthdr->MinorSubsystemVersion = 2;
opthdr->Subsystem = kNtImageSubsystemWindowsCui;
opthdr->DllCharacteristics = kNtImageDllcharacteristicsNxCompat |
kNtImageDllcharacteristicsHighEntropyVa;
@ -1116,7 +1139,7 @@ int main(int argc, char *argv[]) {
// translate executable
struct Elf *elf = OpenElf(argv[optind]);
char *buf = Memalign(MAX_ALIGN, 134217728);
struct ImagePointer ip = GeneratePe(elf, buf, 0x00400000);
struct ImagePointer ip = GeneratePe(elf, buf);
if (creat(outpath, 0755) == -1)
DieSys(elf->path);
Pwrite(3, buf, ip.fp - buf, 0);