Mercurial > repos > blastem
changeset 2406:8e86cd581620
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 | b50fa7602e39 |
| children | 7d851046f035 |
| files | mem.c |
| diffstat | 1 files changed, 4 insertions(+), 7 deletions(-) [+] |
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--- a/mem.c Tue Jan 02 18:23:15 2024 -0800 +++ b/mem.c Tue Jan 02 21:07:09 2024 -0800 @@ -17,15 +17,11 @@ #define MAP_ANONYMOUS MAP_ANON #endif -#ifndef MAP_32BIT -#define MAP_32BIT 0 -#endif - void * alloc_code(size_t *size) { - //start at the 1GB mark to allow plenty of room for sbrk based malloc implementations + //start at 1GB above compiled code to allow plenty of room for sbrk based malloc implementations //while still keeping well within 32-bit displacement range for calling code compiled into the executable - static uint8_t *next = (uint8_t *)0x40000000; + static uint8_t *next = ((uint8_t *)alloc_code) + 0x40000000; uint8_t *ret = try_alloc_arena(); if (ret) { return ret; @@ -33,11 +29,12 @@ if (*size & (PAGE_SIZE -1)) { *size += PAGE_SIZE - (*size & (PAGE_SIZE - 1)); } - ret = mmap(next, *size, PROT_EXEC | PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS | MAP_32BIT, -1, 0); + ret = mmap(next, *size, PROT_EXEC | PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); if (ret == MAP_FAILED) { perror("alloc_code"); return NULL; } + printf("alloc_code next was %p, ret is %p, alloc_code address %p\n", next, ret, alloc_code); track_block(ret); next = ret + *size; return ret;