+ 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;
+}
projects / qemu.git / blobdiff