mirror of
https://github.com/jkdansereau/goldeneye-pc-port.git
synced 2026-10-23 15:52:42 +02:00
port(romdata): POSIX fixed-address ROM map (mmap) for the Linux build
The cart-base map at 0x10000000 (so absolute ROM-asset symbols are live host pointers) was Windows-only; the #else branch was a stub that logged "not implemented" and fell to the degraded heap-copy path. - Factor the post-map work (memcpy + pcmodels/pccg sidecar load + D55 RLE header fixup) into romdataFinishCartMap(), shared by both paths. - POSIX #else: anonymous mmap at CART_BASE with MAP_FIXED_NOREPLACE where available; on any failure munmap + fall through to the identical heap copy. - romdataDestroy() munmaps on POSIX (length tracked in mappedLen). Verified on Windows: builds 242/242, -level_09 boots crash-free (identical behaviour with/without the refactor). Linux compile + runtime verification owed — see docs/dev/LINUX-PORT.md. No behaviour change on Windows.
This commit is contained in:
James Dansereau committed
1 parent
702dee61fc
commit
b01c7fa89c
2 files changed
+168
-44
No files matched your search
@@ -0,0 +1,91 @@
|
||||
# Linux port — status & gap analysis
|
||||
|
||||
Session M-38 (2026-09-02). Goal-2 on the roadmap (after the Windows alpha /
|
||||
release artifact). This is a scoping + first-patch pass; **nothing here has run
|
||||
on a Linux machine yet.**
|
||||
|
||||
## Method
|
||||
|
||||
Read `build-pc.sh`, `CMakeLists.txt`, `docs/building.md`, and grepped
|
||||
`port/src`, `port/fast3d`, `port/include` for Windows-only headers / Win32 APIs
|
||||
/ unguarded `_WIN32` branches. A local Qwen `triage` pass seeded the hunt; every
|
||||
claim below was re-checked against the real files (the 27B was wrong on two of
|
||||
three headline items — see "Ruled out").
|
||||
|
||||
## What is already Linux-ready (verified by reading)
|
||||
|
||||
- **`port/include/platform.h`** — sets `PLATFORM_LINUX` / `PLATFORM_MACOS` /
|
||||
`PLATFORM_WINDOWS` cleanly.
|
||||
- **`CMakeLists.txt`** — `find_package(SDL2 REQUIRED)`, `find_package(ZLIB
|
||||
REQUIRED)`, and `else()` branches already present for the non-Windows case:
|
||||
`GL_LIBRARY = GL` (l.291), `EXTRA_LIBRARIES = stdc++ m dl pthread` (l.304),
|
||||
`elseif(UNIX)` platform block (l.86). `WIN32_EXECUTABLE` and the MinGW zlib
|
||||
fallback are correctly `if(WIN32)` / `if(MINGW)` guarded.
|
||||
- **`build-pc.sh`** — already documents the Linux apt deps
|
||||
(`cmake libsdl2-dev zlib1g-dev libgl1-mesa-dev`) and is a plain bash script,
|
||||
no MSYS-isms in the executable body.
|
||||
- **`port/src/system.c`** — `sysSleep()` has a `nanosleep()` `#else` branch
|
||||
(l.76-82); `<windows.h>` is `PLATFORM_WINDOWS`-guarded.
|
||||
- **`port/src/libultra.c`** — the OS-thread kernel has a real pthreads branch
|
||||
next to the Win32 `_beginthreadex` one.
|
||||
- **`port/src/crash.c`** — `MessageBoxW` / `SetThreadPriority` / `__debugbreak`
|
||||
all `_WIN32`-guarded, with `PLATFORM_LINUX` counterparts.
|
||||
- **`port/src/video.c`** — `GE_MKDIR` has both `_mkdir` and `mkdir(p,0777)`.
|
||||
- No `__declspec`, `#pragma comment`, or hardcoded `\`-path / drive-letter
|
||||
usage anywhere in `port/`.
|
||||
|
||||
## Ruled out (Qwen triage false positives)
|
||||
|
||||
- ~~`system.c:75` `Sleep()` has no POSIX branch~~ — it does (`nanosleep`).
|
||||
- ~~CMake needs `else()` branches for zlib/pthread on Linux~~ — already there.
|
||||
|
||||
## The one real code gap — FIXED this session (verification owed)
|
||||
|
||||
**`port/src/romdata.c`** — the fixed-address cart map (`0x10000000`, so absolute
|
||||
ROM-asset symbols are live host pointers) had a **Windows-only** implementation
|
||||
(`VirtualAlloc`); the `#else` branch was a stub that logged "not implemented on
|
||||
this platform" and fell straight to the heap-copy fallback. In heap-copy mode
|
||||
anything that dereferences a cart address *directly* (not via
|
||||
`romdataGetRom()` / the PI shims) reads wrong memory — so Linux would run, if at
|
||||
all, in the same degraded mode Windows only hits when `VirtualAlloc` loses the
|
||||
address race.
|
||||
|
||||
**Change (M-38):**
|
||||
- Factored the post-map work (memcpy + `pcmodelsLoadSidecars` +
|
||||
`pccgLoadSidecars` + D55 RLE-header fixup) into `romdataFinishCartMap()`,
|
||||
shared by both paths so they cannot drift.
|
||||
- POSIX `#else` now does an anonymous `mmap((void*)CART_BASE, len,
|
||||
PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED_NOREPLACE, -1, 0)`.
|
||||
`MAP_FIXED_NOREPLACE` (Linux 4.17+) fails rather than clobbering an existing
|
||||
mapping; where the macro is absent the plain hint is advisory and the
|
||||
`at == CART_BASE` check catches a relocated result. On any failure it
|
||||
`munmap`s and falls through to the identical heap-copy path as before.
|
||||
- `romdataDestroy()` `munmap`s on POSIX (tracked length in `mappedLen`).
|
||||
|
||||
**Owed verification (needs a Linux box):**
|
||||
1. Compiles under GCC on Linux (`<sys/mman.h>` resolves; no decomp-include-path
|
||||
shadowing surprise).
|
||||
2. `mmap` actually lands at `0x10000000` on a stock ASLR Linux — `0x10000000`
|
||||
(256 MB) is low but usually free; if the kernel routinely refuses it,
|
||||
consider linking the binary no-PIE or reserving the range via a linker
|
||||
script so the loader keeps it clear.
|
||||
3. `-level_09` boots crash-free with the mapped path taken (check the log says
|
||||
"mapped at 0x10000000 (cart base)", not "using heap copy").
|
||||
4. Whether the heap-copy fallback is actually survivable on Linux if step 2
|
||||
fails — audit for direct `0x1xxxxxxx` derefs outside the PI shims.
|
||||
|
||||
## Remaining Linux work after the romdata patch lands
|
||||
|
||||
| # | Item | Size | Note |
|
||||
|---|------|------|------|
|
||||
| 1 | Run the Ubuntu **`validate`** CI job → upgrade it to a real **compile** job | S | `.github/workflows/ci.yml` already configures on Ubuntu; flipping it to `cmake --build` surfaces the real GCC-strictness gaps cheaply |
|
||||
| 2 | First actual Linux runtime bring-up (`-level_09`) | M | expect a short tail of unguarded calls / struct-layout asserts GCC-on-Linux vs MinGW |
|
||||
| 3 | `docs/building.md` — promote Linux from "untested" to "supported" once 1+2 pass | S | |
|
||||
| 4 | SDL2 / GL context creation on X11 + Wayland | M | fast3d is GL 3.3 core; PD port runs on Linux so the path is known-good |
|
||||
| 5 | Package: an AppImage or tarball equivalent of `bundle-win.sh` | M | reuse `prepare-assets.py` verbatim — it is already OS-agnostic |
|
||||
|
||||
## Recommended next step
|
||||
|
||||
Land the romdata patch behind CI (item 1) — turn the Ubuntu `validate` job into
|
||||
a compile job in the same PR so the "does it build on Linux" question is
|
||||
answered by the bots, then do the runtime bring-up on a real machine.
|
||||
+77
-44
@@ -32,6 +32,11 @@ extern int snprintf(char *str, unsigned long long maxsize, const char *format, .
|
||||
#define WIN32_LEAN_AND_MEAN
|
||||
#endif
|
||||
#include <windows.h>
|
||||
#else
|
||||
/* POSIX: mmap the ROM at the fixed cart address (mirrors the VirtualAlloc
|
||||
* path). <sys/mman.h> is a host header the decomp include path does not
|
||||
* shadow. */
|
||||
#include <sys/mman.h>
|
||||
#endif
|
||||
|
||||
#include "system.h"
|
||||
@@ -50,6 +55,9 @@ extern int snprintf(char *str, unsigned long long maxsize, const char *format, .
|
||||
static u8 *rom = NULL; /* heap copy (fallback path) */
|
||||
static u32 romSize = 0;
|
||||
static int mappedAtCartBase = 0;
|
||||
#if !defined(PLATFORM_WINDOWS)
|
||||
static unsigned long long mappedLen = 0; /* munmap() needs the length */
|
||||
#endif
|
||||
|
||||
/* D34 (docs/internals.md): PE image base, low 32 bits zero. On N64 the
|
||||
* animation_data segment links at VMA 0, so game code computes record
|
||||
@@ -105,6 +113,35 @@ static int romHeaderValid(const u8 *h, char *err, size_t errsz)
|
||||
|
||||
static u32 romdataBswap32(u32 v); /* defined below; used by the D55 fixup */
|
||||
|
||||
/* The caller has placed a writable region of (romSize + sidecars) bytes at
|
||||
* CART_BASE. Populate it, load the sidecars, apply the D55 RLE-header fixup,
|
||||
* and mark the ROM live. Shared by the Windows (VirtualAlloc) and POSIX (mmap)
|
||||
* fixed-address paths so the post-map logic can never drift between them. */
|
||||
static int romdataFinishCartMap(const char *tok, u8 *img,
|
||||
u32 sideTotal, u32 cgTotal)
|
||||
{
|
||||
memcpy((void *)(uintptr_t)CART_BASE, img, romSize);
|
||||
free(img);
|
||||
mappedAtCartBase = 1;
|
||||
sysLogPrintf(LOG_INFO, "romdataInit: %s (%u bytes) mapped at 0x%08X "
|
||||
"(cart base)%s%s", tok, romSize, CART_BASE,
|
||||
sideTotal ? ", + model sidecars" : "",
|
||||
cgTotal ? ", + bg/stan sidecars" : "");
|
||||
pcmodelsLoadSidecars(CART_BASE, romSize);
|
||||
pccgLoadSidecars(CART_BASE + romSize + pcmodelsTotalSize());
|
||||
|
||||
/* D55: the RLE folder-menu background at `unknown2` has a big-endian w/h
|
||||
* header that rle_expand_8bit() reads little-endian; match the N64 .data
|
||||
* copy by swapping it in place (no-op if it already reads as LE). */
|
||||
{
|
||||
extern void *unknown2; /* absolute cart address */
|
||||
u32 *hdr = (u32 *)&unknown2;
|
||||
if ((u16)*hdr > 512 || (u16)(*hdr >> 16) > 512)
|
||||
*hdr = romdataBswap32(*hdr);
|
||||
}
|
||||
return 0;
|
||||
}
|
||||
|
||||
int romdataInit(void)
|
||||
{
|
||||
char err[128] = "";
|
||||
@@ -168,51 +205,44 @@ int romdataInit(void)
|
||||
* sidecar extension. */
|
||||
u32 cgTotal = pccgReserveSize(img);
|
||||
|
||||
/* Map at the cart address so absolute asset symbols are live. */
|
||||
/* Map at the cart address so absolute asset symbols are live. On
|
||||
* failure both paths fall through to the heap copy below (degraded:
|
||||
* anything that dereferences a cart address directly, rather than via
|
||||
* romdataGetRom()/the PI shims, will read wrong memory). */
|
||||
{
|
||||
u32 maplen = romSize + sideTotal + cgTotal;
|
||||
#if defined(PLATFORM_WINDOWS)
|
||||
void *at = VirtualAlloc((LPVOID)CART_BASE, romSize + sideTotal + cgTotal,
|
||||
MEM_RESERVE | MEM_COMMIT, PAGE_READWRITE);
|
||||
if (at == (void *)(uintptr_t)CART_BASE) {
|
||||
memcpy(at, img, romSize);
|
||||
free(img);
|
||||
mappedAtCartBase = 1;
|
||||
sysLogPrintf(LOG_INFO, "romdataInit: %s (%u bytes) mapped at "
|
||||
"0x%08X (cart base)%s%s",
|
||||
tok, romSize, CART_BASE,
|
||||
sideTotal ? ", + model sidecars" : "",
|
||||
cgTotal ? ", + bg/stan sidecars" : "");
|
||||
pcmodelsLoadSidecars(CART_BASE, romSize);
|
||||
pccgLoadSidecars(CART_BASE + romSize + pcmodelsTotalSize());
|
||||
|
||||
/* D55 (docs/internals.md): the RLE folder-menu background at
|
||||
* `unknown2` (romassets_<r>.s) is stored in the ROM with a
|
||||
* big-endian w/h header (01 B8 01 2B = 440x299), but
|
||||
* rle_expand_8bit() reads it little-endian. The N64 build embeds
|
||||
* this asset into .data via assets/romfiles2.s from an extracted
|
||||
* .bin whose header is byte-swapped (title2.c hardcodes 440x299
|
||||
* row rendering, and this is the only decodable 440x299 RLE
|
||||
* stream in the ROM), so make the cart copy match it: swap the
|
||||
* w/h word in place. The guard makes the fixup a no-op if a
|
||||
* region's copy already reads as a plausible LE size. */
|
||||
{
|
||||
extern void *unknown2; /* absolute cart address */
|
||||
u32 *hdr = (u32 *)&unknown2;
|
||||
if ((u16)*hdr > 512 || (u16)(*hdr >> 16) > 512)
|
||||
*hdr = romdataBswap32(*hdr);
|
||||
}
|
||||
return 0;
|
||||
}
|
||||
if (at)
|
||||
VirtualFree(at, 0, MEM_RELEASE);
|
||||
sysLogPrintf(LOG_WARNING, "romdataInit: could not reserve 0x%08X; "
|
||||
"using heap copy — direct ROM reads will fail",
|
||||
CART_BASE);
|
||||
void *at = VirtualAlloc((LPVOID)CART_BASE, maplen,
|
||||
MEM_RESERVE | MEM_COMMIT, PAGE_READWRITE);
|
||||
if (at == (void *)(uintptr_t)CART_BASE)
|
||||
return romdataFinishCartMap(tok, img, sideTotal, cgTotal);
|
||||
if (at)
|
||||
VirtualFree(at, 0, MEM_RELEASE);
|
||||
sysLogPrintf(LOG_WARNING, "romdataInit: could not reserve 0x%08X; "
|
||||
"using heap copy — direct ROM reads will fail",
|
||||
CART_BASE);
|
||||
#else
|
||||
/* Best effort: fixed-hint mmap. If the hint is refused we fall back
|
||||
* to a heap copy (same limitation as above). */
|
||||
sysLogPrintf(LOG_WARNING, "romdataInit: fixed-address mapping not "
|
||||
"implemented on this platform; using heap copy");
|
||||
/* POSIX: anonymous fixed-address mmap. MAP_FIXED_NOREPLACE (Linux
|
||||
* 4.17+) fails instead of clobbering an existing mapping; where it
|
||||
* is unavailable the plain hint is advisory and the == check below
|
||||
* catches a relocated result. */
|
||||
int flags = MAP_PRIVATE | MAP_ANONYMOUS;
|
||||
#ifdef MAP_FIXED_NOREPLACE
|
||||
flags |= MAP_FIXED_NOREPLACE;
|
||||
#endif
|
||||
void *at = mmap((void *)(uintptr_t)CART_BASE, maplen,
|
||||
PROT_READ | PROT_WRITE, flags, -1, 0);
|
||||
if (at != MAP_FAILED && at == (void *)(uintptr_t)CART_BASE) {
|
||||
mappedLen = maplen;
|
||||
return romdataFinishCartMap(tok, img, sideTotal, cgTotal);
|
||||
}
|
||||
if (at != MAP_FAILED)
|
||||
munmap(at, maplen);
|
||||
sysLogPrintf(LOG_WARNING, "romdataInit: could not map 0x%08X "
|
||||
"(ASLR/kernel refused the fixed address); using heap "
|
||||
"copy — direct ROM reads will fail", CART_BASE);
|
||||
#endif
|
||||
}
|
||||
|
||||
rom = img;
|
||||
return 0;
|
||||
@@ -225,12 +255,15 @@ int romdataInit(void)
|
||||
|
||||
void romdataDestroy(void)
|
||||
{
|
||||
#if defined(PLATFORM_WINDOWS)
|
||||
if (mappedAtCartBase) {
|
||||
#if defined(PLATFORM_WINDOWS)
|
||||
VirtualFree((LPVOID)CART_BASE, 0, MEM_RELEASE);
|
||||
#else
|
||||
munmap((void *)(uintptr_t)CART_BASE, (size_t)mappedLen);
|
||||
mappedLen = 0;
|
||||
#endif
|
||||
mappedAtCartBase = 0;
|
||||
}
|
||||
#endif
|
||||
free(rom);
|
||||
rom = NULL;
|
||||
romSize = 0;
|
||||
|
||||
Reference in new issue
Block a user