diff options
Diffstat (limited to 'rts/Linker.c')
| -rw-r--r-- | rts/Linker.c | 85 |
1 files changed, 77 insertions, 8 deletions
diff --git a/rts/Linker.c b/rts/Linker.c index 4b551f0073..a8ab511719 100644 --- a/rts/Linker.c +++ b/rts/Linker.c @@ -188,7 +188,7 @@ int ocTryLoad( ObjectCode* oc ); * * MAP_32BIT not available on OpenBSD/amd64 */ -#if defined(MAP_32BIT) && defined(x86_64_HOST_ARCH) +#if defined(MAP_32BIT) && (defined(x86_64_HOST_ARCH) || (defined(aarch64_TARGET_ARCH) || defined(aarch64_HOST_ARCH))) #define MAP_LOW_MEM #define TRY_MAP_32BIT MAP_32BIT #else @@ -214,10 +214,22 @@ int ocTryLoad( ObjectCode* oc ); * systems, we have to pick a base address in the low 2Gb of the address space * and try to allocate memory from there. * + * The same holds for aarch64, where the default, even with PIC, model + * is 4GB. The linker is free to emit AARCH64_ADR_PREL_PG_HI21 + * relocations. + * * We pick a default address based on the OS, but also make this * configurable via an RTS flag (+RTS -xm) */ -#if defined(MAP_32BIT) || DEFAULT_LINKER_ALWAYS_PIC + +#if (defined(aarch64_TARGET_ARCH) || defined(aarch64_HOST_ARCH)) +// Try to use stg_upd_frame_info as the base. We need to be within +-4GB of that +// address, otherwise we violate the aarch64 memory model. Any object we load +// can potentially reference any of the ones we bake into the binary (and list) +// in RtsSymbols. Thus we'll need to be within +-4GB of those, +// stg_upd_frame_info is a good candidate as it's referenced often. +#define MMAP_32BIT_BASE_DEFAULT (void*)&stg_upd_frame_info; +#elif defined(MAP_32BIT) || DEFAULT_LINKER_ALWAYS_PIC // Try to use MAP_32BIT #define MMAP_32BIT_BASE_DEFAULT 0 #else @@ -1040,11 +1052,47 @@ resolveSymbolAddr (pathchar* buffer, int size, } #if RTS_LINKER_USE_MMAP + +/* ----------------------------------------------------------------------------- + Occationally we depend on mmap'd region being close to already mmap'd regions. + + Our static in-memory linker may be restricted by the architectures relocation + range. E.g. aarch64 has a +-4GB range for PIC code, thus we'd preferrably + get memory for the linker close to existing mappings. mmap on it's own is + free to return any memory location, independent of what the preferred + location argument indicates. + + For example mmap (via qemu) might give you addresses all over the available + memory range if the requested location is already occupied. + + mmap_next will do a linear search from the start page upwards to find a + suitable location that is as close as possible to the locations (proivded + via the first argument). + -------------------------------------------------------------------------- */ + +void* +mmap_next(void *addr, size_t length, int prot, int flags, int fd, off_t offset) { + if(addr == NULL) return mmap(addr, length, prot, flags, fd, offset); + // we are going to look for up to pageSize * 1024 * 1024 (4GB) from the + // address. + size_t pageSize = getPageSize(); + for(int i = (uintptr_t)addr & (pageSize-1) ? 1 : 0; i < 1024*1024; i++) { + void *target = (void*)(((uintptr_t)addr & ~(pageSize-1))+(i*pageSize)); + void *mem = mmap(target, length, prot, flags, fd, offset); + if(mem == NULL) return mem; + if(mem == target) return mem; + munmap(mem, length); + IF_DEBUG(linker && (i % 1024 == 0), + debugBelch("mmap_next failed to find suitable space in %p - %p\n", addr, target)); + } + return NULL; +} + // // Returns NULL on failure. // void * -mmapForLinker (size_t bytes, uint32_t flags, int fd, int offset) +mmapForLinker (size_t bytes, uint32_t prot, uint32_t flags, int fd, int offset) { void *map_addr = NULL; void *result; @@ -1065,15 +1113,14 @@ mmap_again: map_addr = mmap_32bit_base; } - const int prot = PROT_READ | PROT_WRITE; IF_DEBUG(linker, debugBelch("mmapForLinker: \tprotection %#0x\n", prot)); IF_DEBUG(linker, debugBelch("mmapForLinker: \tflags %#0x\n", MAP_PRIVATE | tryMap32Bit | fixed | flags)); - result = mmap(map_addr, size, prot, - MAP_PRIVATE|tryMap32Bit|fixed|flags, fd, offset); + result = mmap_next(map_addr, size, prot, + MAP_PRIVATE|tryMap32Bit|fixed|flags, fd, offset); if (result == MAP_FAILED) { sysErrorBelch("mmap %" FMT_Word " bytes at %p",(W_)size,map_addr); @@ -1126,6 +1173,28 @@ mmap_again: goto mmap_again; } } +#elif (defined(aarch64_TARGET_ARCH) || defined(aarch64_HOST_ARCH)) + // for aarch64 we need to make sure we stay within 4GB of the + // mmap_32bit_base, and we also do not want to update it. +// if (mmap_32bit_base != (void*)&stg_upd_frame_info) { + if (result == map_addr) { + mmap_32bit_base = (void*)((uintptr_t)map_addr + size); + } else { + // upper limit 4GB - size of the object file - 1mb wiggle room. + if(llabs((uintptr_t)result - (uintptr_t)&stg_upd_frame_info) > (2<<32) - size - (2<<20)) { + // not within range :( + debugTrace(DEBUG_linker, + "MAP_32BIT didn't work; gave us %lu bytes at 0x%p", + bytes, result); + munmap(result, size); + // TODO: some abort/mmap_32bit_base recomputation based on + // if mmap_32bit_base is changed, or still at stg_upd_frame_info + goto mmap_again; + } else { + mmap_32bit_base = (void*)((uintptr_t)result + size); + } + } +// } #endif IF_DEBUG(linker, @@ -1454,9 +1523,9 @@ preloadObjectFile (pathchar *path) * See also the misalignment logic for darwin below. */ #if defined(ios_HOST_OS) - image = mmap(NULL, fileSize, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0); + image = mmapForLinker(fileSize, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0); #else - image = mmap(NULL, fileSize, PROT_READ|PROT_WRITE|PROT_EXEC, + image = mmapForLinker(fileSize, PROT_READ|PROT_WRITE|PROT_EXEC, MAP_PRIVATE, fd, 0); #endif |