Mercurial > repos > blastem

comparison mem.c @ 2406:8e86cd581620

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
Better implementation of alloc_code for ASLR/libretro cases that also hopefully works on modern Mac OS
author Michael Pavone <pavone@retrodev.com>
date Tue, 02 Jan 2024 21:07:09 -0800
parents 101b5ce682fe
children 7d851046f035
comparison
equal deleted inserted replaced
2405:b50fa7602e39 2406:8e86cd581620
15 #include "arena.h" 15 #include "arena.h"
16 #ifndef MAP_ANONYMOUS 16 #ifndef MAP_ANONYMOUS
17 #define MAP_ANONYMOUS MAP_ANON 17 #define MAP_ANONYMOUS MAP_ANON
18 #endif 18 #endif
19 19
20 #ifndef MAP_32BIT
21 #define MAP_32BIT 0
22 #endif
23
24 void * alloc_code(size_t *size) 20 void * alloc_code(size_t *size)
25 { 21 {
26 //start at the 1GB mark to allow plenty of room for sbrk based malloc implementations 22 //start at 1GB above compiled code to allow plenty of room for sbrk based malloc implementations
27 //while still keeping well within 32-bit displacement range for calling code compiled into the executable 23 //while still keeping well within 32-bit displacement range for calling code compiled into the executable
28 static uint8_t *next = (uint8_t *)0x40000000; 24 static uint8_t *next = ((uint8_t *)alloc_code) + 0x40000000;
29 uint8_t *ret = try_alloc_arena(); 25 uint8_t *ret = try_alloc_arena();
30 if (ret) { 26 if (ret) {
31 return ret; 27 return ret;
32 } 28 }
33 if (*size & (PAGE_SIZE -1)) { 29 if (*size & (PAGE_SIZE -1)) {
34 *size += PAGE_SIZE - (*size & (PAGE_SIZE - 1)); 30 *size += PAGE_SIZE - (*size & (PAGE_SIZE - 1));
35 } 31 }
36 ret = mmap(next, *size, PROT_EXEC | PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS | MAP_32BIT, -1, 0); 32 ret = mmap(next, *size, PROT_EXEC | PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
37 if (ret == MAP_FAILED) { 33 if (ret == MAP_FAILED) {
38 perror("alloc_code"); 34 perror("alloc_code");
39 return NULL; 35 return NULL;
40 } 36 }
37 printf("alloc_code next was %p, ret is %p, alloc_code address %p\n", next, ret, alloc_code);
41 track_block(ret); 38 track_block(ret);
42 next = ret + *size; 39 next = ret + *size;
43 return ret; 40 return ret;
44 } 41 }
45 42