diff options
Diffstat (limited to 'exec.c')
| -rw-r--r-- | exec.c | 238 |
1 files changed, 127 insertions, 111 deletions
diff --git a/exec.c b/exec.c index 17e8ba21d4..5b55e3e9ed 100644 --- a/exec.c +++ b/exec.c @@ -85,26 +85,11 @@ static int nb_tbs; /* any access to the tbs or the page table must use this lock */ spinlock_t tb_lock = SPIN_LOCK_UNLOCKED; -#if defined(__arm__) || defined(__sparc__) -/* The prologue must be reachable with a direct jump. ARM and Sparc64 - have limited branch ranges (possibly also PPC) so place it in a - section close to code segment. */ -#define code_gen_section \ - __attribute__((__section__(".gen_code"))) \ - __attribute__((aligned (32))) -#elif defined(_WIN32) && !defined(_WIN64) -#define code_gen_section \ - __attribute__((aligned (16))) -#else -#define code_gen_section \ - __attribute__((aligned (32))) -#endif - -uint8_t code_gen_prologue[1024] code_gen_section; +uint8_t *code_gen_prologue; static uint8_t *code_gen_buffer; -static unsigned long code_gen_buffer_size; +static size_t code_gen_buffer_size; /* threshold to flush the translated code buffer */ -static unsigned long code_gen_buffer_max_size; +static size_t code_gen_buffer_max_size; static uint8_t *code_gen_ptr; #if !defined(CONFIG_USER_ONLY) @@ -212,7 +197,7 @@ static int tb_flush_count; static int tb_phys_invalidate_count; #ifdef _WIN32 -static void map_exec(void *addr, long size) +static inline void map_exec(void *addr, long size) { DWORD old_protect; VirtualProtect(addr, size, @@ -220,7 +205,7 @@ static void map_exec(void *addr, long size) } #else -static void map_exec(void *addr, long size) +static inline void map_exec(void *addr, long size) { unsigned long start, end, page_size; @@ -489,111 +474,142 @@ bool memory_region_is_unassigned(MemoryRegion *mr) #define mmap_unlock() do { } while(0) #endif -#define DEFAULT_CODE_GEN_BUFFER_SIZE (32 * 1024 * 1024) - #if defined(CONFIG_USER_ONLY) /* Currently it is not recommended to allocate big chunks of data in - user mode. It will change when a dedicated libc will be used */ + user mode. It will change when a dedicated libc will be used. */ +/* ??? 64-bit hosts ought to have no problem mmaping data outside the + region in which the guest needs to run. Revisit this. */ #define USE_STATIC_CODE_GEN_BUFFER #endif -#ifdef USE_STATIC_CODE_GEN_BUFFER -static uint8_t static_code_gen_buffer[DEFAULT_CODE_GEN_BUFFER_SIZE] - __attribute__((aligned (CODE_GEN_ALIGN))); +/* ??? Should configure for this, not list operating systems here. */ +#if (defined(__linux__) \ + || defined(__FreeBSD__) || defined(__FreeBSD_kernel__) \ + || defined(__DragonFly__) || defined(__OpenBSD__) \ + || defined(__NetBSD__)) +# define USE_MMAP #endif -static void code_gen_alloc(unsigned long tb_size) -{ -#ifdef USE_STATIC_CODE_GEN_BUFFER - code_gen_buffer = static_code_gen_buffer; - code_gen_buffer_size = DEFAULT_CODE_GEN_BUFFER_SIZE; - map_exec(code_gen_buffer, code_gen_buffer_size); -#else - code_gen_buffer_size = tb_size; - if (code_gen_buffer_size == 0) { -#if defined(CONFIG_USER_ONLY) - code_gen_buffer_size = DEFAULT_CODE_GEN_BUFFER_SIZE; -#else - /* XXX: needs adjustments */ - code_gen_buffer_size = (unsigned long)(ram_size / 4); -#endif - } - if (code_gen_buffer_size < MIN_CODE_GEN_BUFFER_SIZE) - code_gen_buffer_size = MIN_CODE_GEN_BUFFER_SIZE; - /* The code gen buffer location may have constraints depending on - the host cpu and OS */ -#if defined(__linux__) - { - int flags; - void *start = NULL; +/* Minimum size of the code gen buffer. This number is randomly chosen, + but not so small that we can't have a fair number of TB's live. */ +#define MIN_CODE_GEN_BUFFER_SIZE (1024u * 1024) - flags = MAP_PRIVATE | MAP_ANONYMOUS; +/* Maximum size of the code gen buffer we'd like to use. Unless otherwise + indicated, this is constrained by the range of direct branches on the + host cpu, as used by the TCG implementation of goto_tb. */ #if defined(__x86_64__) - flags |= MAP_32BIT; - /* Cannot map more than that */ - if (code_gen_buffer_size > (800 * 1024 * 1024)) - code_gen_buffer_size = (800 * 1024 * 1024); -#elif defined(__sparc__) && HOST_LONG_BITS == 64 - // Map the buffer below 2G, so we can use direct calls and branches - start = (void *) 0x40000000UL; - if (code_gen_buffer_size > (512 * 1024 * 1024)) - code_gen_buffer_size = (512 * 1024 * 1024); +# define MAX_CODE_GEN_BUFFER_SIZE (2ul * 1024 * 1024 * 1024) +#elif defined(__sparc__) +# define MAX_CODE_GEN_BUFFER_SIZE (2ul * 1024 * 1024 * 1024) #elif defined(__arm__) - /* Keep the buffer no bigger than 16MB to branch between blocks */ - if (code_gen_buffer_size > 16 * 1024 * 1024) - code_gen_buffer_size = 16 * 1024 * 1024; +# define MAX_CODE_GEN_BUFFER_SIZE (16u * 1024 * 1024) #elif defined(__s390x__) - /* Map the buffer so that we can use direct calls and branches. */ - /* We have a +- 4GB range on the branches; leave some slop. */ - if (code_gen_buffer_size > (3ul * 1024 * 1024 * 1024)) { - code_gen_buffer_size = 3ul * 1024 * 1024 * 1024; - } - start = (void *)0x90000000UL; + /* We have a +- 4GB range on the branches; leave some slop. */ +# define MAX_CODE_GEN_BUFFER_SIZE (3ul * 1024 * 1024 * 1024) +#else +# define MAX_CODE_GEN_BUFFER_SIZE ((size_t)-1) #endif - code_gen_buffer = mmap(start, code_gen_buffer_size, - PROT_WRITE | PROT_READ | PROT_EXEC, - flags, -1, 0); - if (code_gen_buffer == MAP_FAILED) { - fprintf(stderr, "Could not allocate dynamic translator buffer\n"); - exit(1); - } - } -#elif defined(__FreeBSD__) || defined(__FreeBSD_kernel__) \ - || defined(__DragonFly__) || defined(__OpenBSD__) \ - || defined(__NetBSD__) - { - int flags; - void *addr = NULL; - flags = MAP_PRIVATE | MAP_ANONYMOUS; -#if defined(__x86_64__) - /* FreeBSD doesn't have MAP_32BIT, use MAP_FIXED and assume - * 0x40000000 is free */ - flags |= MAP_FIXED; - addr = (void *)0x40000000; - /* Cannot map more than that */ - if (code_gen_buffer_size > (800 * 1024 * 1024)) - code_gen_buffer_size = (800 * 1024 * 1024); -#elif defined(__sparc__) && HOST_LONG_BITS == 64 - // Map the buffer below 2G, so we can use direct calls and branches - addr = (void *) 0x40000000UL; - if (code_gen_buffer_size > (512 * 1024 * 1024)) { - code_gen_buffer_size = (512 * 1024 * 1024); - } + +#define DEFAULT_CODE_GEN_BUFFER_SIZE_1 (32u * 1024 * 1024) + +#define DEFAULT_CODE_GEN_BUFFER_SIZE \ + (DEFAULT_CODE_GEN_BUFFER_SIZE_1 < MAX_CODE_GEN_BUFFER_SIZE \ + ? DEFAULT_CODE_GEN_BUFFER_SIZE_1 : MAX_CODE_GEN_BUFFER_SIZE) + +static inline size_t size_code_gen_buffer(size_t tb_size) +{ + /* Size the buffer. */ + if (tb_size == 0) { +#ifdef USE_STATIC_CODE_GEN_BUFFER + tb_size = DEFAULT_CODE_GEN_BUFFER_SIZE; +#else + /* ??? Needs adjustments. */ + /* ??? If we relax the requirement that CONFIG_USER_ONLY use the + static buffer, we could size this on RESERVED_VA, on the text + segment size of the executable, or continue to use the default. */ + tb_size = (unsigned long)(ram_size / 4); #endif - code_gen_buffer = mmap(addr, code_gen_buffer_size, - PROT_WRITE | PROT_READ | PROT_EXEC, - flags, -1, 0); - if (code_gen_buffer == MAP_FAILED) { - fprintf(stderr, "Could not allocate dynamic translator buffer\n"); - exit(1); - } } + if (tb_size < MIN_CODE_GEN_BUFFER_SIZE) { + tb_size = MIN_CODE_GEN_BUFFER_SIZE; + } + if (tb_size > MAX_CODE_GEN_BUFFER_SIZE) { + tb_size = MAX_CODE_GEN_BUFFER_SIZE; + } + code_gen_buffer_size = tb_size; + return tb_size; +} + +#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, code_gen_buffer_size); + return static_code_gen_buffer; +} +#elif defined(USE_MMAP) +static inline void *alloc_code_gen_buffer(void) +{ + int flags = MAP_PRIVATE | MAP_ANONYMOUS; + uintptr_t start = 0; + void *buf; + + /* Constrain the position of the buffer based on the host cpu. + Note that these addresses are chosen in concert with the + addresses assigned in the relevant linker script file. */ +# if defined(__PIE__) || defined(__PIC__) + /* Don't bother setting a preferred location if we're building + a position-independent executable. We're more likely to get + an address near the main executable if we let the kernel + choose the address. */ +# elif defined(__x86_64__) && defined(MAP_32BIT) + /* Force the memory down into low memory with the executable. + Leave the choice of exact location with the kernel. */ + flags |= MAP_32BIT; + /* Cannot expect to map more than 800MB in low memory. */ + if (code_gen_buffer_size > 800u * 1024 * 1024) { + code_gen_buffer_size = 800u * 1024 * 1024; + } +# elif defined(__sparc__) + start = 0x40000000ul; +# elif defined(__s390x__) + start = 0x90000000ul; +# endif + + buf = mmap((void *)start, code_gen_buffer_size, + PROT_WRITE | PROT_READ | PROT_EXEC, flags, -1, 0); + return buf == MAP_FAILED ? NULL : buf; +} #else - code_gen_buffer = g_malloc(code_gen_buffer_size); - map_exec(code_gen_buffer, code_gen_buffer_size); -#endif -#endif /* !USE_STATIC_CODE_GEN_BUFFER */ - map_exec(code_gen_prologue, sizeof(code_gen_prologue)); +static inline void *alloc_code_gen_buffer(void) +{ + void *buf = g_malloc(code_gen_buffer_size); + if (buf) { + map_exec(buf, code_gen_buffer_size); + } + return buf; +} +#endif /* USE_STATIC_CODE_GEN_BUFFER, USE_MMAP */ + +static inline void code_gen_alloc(size_t tb_size) +{ + code_gen_buffer_size = size_code_gen_buffer(tb_size); + code_gen_buffer = alloc_code_gen_buffer(); + if (code_gen_buffer == NULL) { + fprintf(stderr, "Could not allocate dynamic translator buffer\n"); + exit(1); + } + + /* Steal room for the prologue at the end of the buffer. This ensures + (via the MAX_CODE_GEN_BUFFER_SIZE limits above) that direct branches + from TB's to the prologue are going to be in range. It also means + that we don't need to mark (additional) portions of the data segment + as executable. */ + code_gen_prologue = code_gen_buffer + code_gen_buffer_size - 1024; + code_gen_buffer_size -= 1024; + code_gen_buffer_max_size = code_gen_buffer_size - (TCG_MAX_OP_SIZE * OPC_BUF_SIZE); code_gen_max_blocks = code_gen_buffer_size / CODE_GEN_AVG_BLOCK_SIZE; @@ -4136,7 +4152,7 @@ void dump_exec_info(FILE *f, fprintf_function cpu_fprintf) } /* XXX: avoid using doubles ? */ cpu_fprintf(f, "Translation buffer state:\n"); - cpu_fprintf(f, "gen code size %td/%ld\n", + cpu_fprintf(f, "gen code size %td/%zd\n", code_gen_ptr - code_gen_buffer, code_gen_buffer_max_size); cpu_fprintf(f, "TB count %d/%d\n", nb_tbs, code_gen_max_blocks); |