diff options
| -rw-r--r-- | translate-all.c | 90 |
1 files changed, 85 insertions, 5 deletions
diff --git a/translate-all.c b/translate-all.c index c631694a6e..6b7b46e761 100644 --- a/translate-all.c +++ b/translate-all.c @@ -513,14 +513,47 @@ static inline size_t size_code_gen_buffer(size_t tb_size) return tb_size; } +#ifdef __mips__ +/* In order to use J and JAL within the code_gen_buffer, we require + that the buffer not cross a 256MB boundary. */ +static inline bool cross_256mb(void *addr, size_t size) +{ + return ((uintptr_t)addr ^ ((uintptr_t)addr + size)) & 0xf0000000; +} + +/* We weren't able to allocate a buffer without crossing that boundary, + so make do with the larger portion of the buffer that doesn't cross. + Returns the new base of the buffer, and adjusts code_gen_buffer_size. */ +static inline void *split_cross_256mb(void *buf1, size_t size1) +{ + void *buf2 = (void *)(((uintptr_t)buf1 + size1) & 0xf0000000); + size_t size2 = buf1 + size1 - buf2; + + size1 = buf2 - buf1; + if (size1 < size2) { + size1 = size2; + buf1 = buf2; + } + + tcg_ctx.code_gen_buffer_size = size1; + return buf1; +} +#endif + #ifdef USE_STATIC_CODE_GEN_BUFFER static uint8_t static_code_gen_buffer[DEFAULT_CODE_GEN_BUFFER_SIZE] __attribute__((aligned(CODE_GEN_ALIGN))); static inline void *alloc_code_gen_buffer(void) { - map_exec(static_code_gen_buffer, tcg_ctx.code_gen_buffer_size); - return static_code_gen_buffer; + void *buf = static_code_gen_buffer; +#ifdef __mips__ + if (cross_256mb(buf, tcg_ctx.code_gen_buffer_size)) { + buf = split_cross_256mb(buf, tcg_ctx.code_gen_buffer_size); + } +#endif + map_exec(buf, tcg_ctx.code_gen_buffer_size); + return buf; } #elif defined(USE_MMAP) static inline void *alloc_code_gen_buffer(void) @@ -562,16 +595,63 @@ static inline void *alloc_code_gen_buffer(void) buf = mmap((void *)start, tcg_ctx.code_gen_buffer_size, PROT_WRITE | PROT_READ | PROT_EXEC, flags, -1, 0); - return buf == MAP_FAILED ? NULL : buf; + if (buf == MAP_FAILED) { + return NULL; + } + +#ifdef __mips__ + if (cross_256mb(buf, tcg_ctx.code_gen_buffer_size)) { + /* Try again, with the original still mapped, to avoid re-aquiring + that 256mb crossing. This time don't specify an address. */ + size_t size2, size1 = tcg_ctx.code_gen_buffer_size; + void *buf2 = mmap(NULL, size1, PROT_WRITE | PROT_READ | PROT_EXEC, + flags, -1, 0); + if (buf2 != MAP_FAILED) { + if (!cross_256mb(buf2, size1)) { + /* Success! Use the new buffer. */ + munmap(buf, size1); + return buf2; + } + /* Failure. Work with what we had. */ + munmap(buf2, size1); + } + + /* Split the original buffer. Free the smaller half. */ + buf2 = split_cross_256mb(buf, size1); + size2 = tcg_ctx.code_gen_buffer_size; + munmap(buf + (buf == buf2 ? size2 : 0), size1 - size2); + return buf2; + } +#endif + + return buf; } #else static inline void *alloc_code_gen_buffer(void) { void *buf = g_malloc(tcg_ctx.code_gen_buffer_size); - if (buf) { - map_exec(buf, tcg_ctx.code_gen_buffer_size); + if (buf == NULL) { + return NULL; } + +#ifdef __mips__ + if (cross_256mb(buf, tcg_ctx.code_gen_buffer_size)) { + void *buf2 = g_malloc(tcg_ctx.code_gen_buffer_size); + if (buf2 != NULL && !cross_256mb(buf2, size1)) { + /* Success! Use the new buffer. */ + free(buf); + buf = buf2; + } else { + /* Failure. Work with what we had. Since this is malloc + and not mmap, we can't free the other half. */ + free(buf2); + buf = split_cross_256mb(buf, tcg_ctx.code_gen_buffer_size); + } + } +#endif + + map_exec(buf, tcg_ctx.code_gen_buffer_size); return buf; } #endif /* USE_STATIC_CODE_GEN_BUFFER, USE_MMAP */ |