diff options
| -rw-r--r-- | lib/objc-asm.S | 2 | ||||
| -rw-r--r-- | lib/objc.c | 23 | ||||
| -rw-r--r-- | lib/objc.h | 4 |
3 files changed, 26 insertions, 3 deletions
diff --git a/lib/objc-asm.S b/lib/objc-asm.S index 7b874c4..bebce80 100644 --- a/lib/objc-asm.S +++ b/lib/objc-asm.S @@ -9,7 +9,7 @@ _remap_start: .set i, 0 -#define my_rpe (0b + (_PAGE_SIZE - i * TRAMPOLINE_SIZE + i * REMAP_PAGE_ENTRY_SIZE)) +#define my_rpe (0b + (_PAGE_SIZE - i * TRAMPOLINE_SIZE + i * TRAMP_INFO_PAGE_ENTRY_SIZE)) .rept TRAMPOLINES_PER_PAGE 0: #if defined(__x86_64__) @@ -15,11 +15,18 @@ * without having to ask whether the selector is stret or not. */ struct tramp_info_page_header { + uint32_t magic; + uint32_t version; struct tramp_info_page_entry *first_free; size_t nfree; LIST_ENTRY(tramp_info_page_header) free_pages; }; +enum { + TRAMP_MAGIC = 0xf00df17e, + TRAMP_VERSION = 0, +}; + struct tramp_info_page_entry { union { struct tramp_info_page_entry *next_free; @@ -29,6 +36,12 @@ struct tramp_info_page_entry { void *arg2; }; +_Static_assert(TRAMP_INFO_PAGE_ENTRY_SIZE == sizeof(struct tramp_info_page_entry), + "TRAMP_INFO_PAGE_ENTRY_SIZE"); +_Static_assert(sizeof(struct tramp_info_page_header) + + TRAMPOLINES_PER_PAGE * sizeof(struct tramp_info_page_entry) <= _PAGE_SIZE, + "header+entries too big"); + static pthread_mutex_t tramp_mutex = PTHREAD_MUTEX_INITIALIZER; LIST_HEAD(tramp_info_page_list, tramp_info_page_header) tramp_free_page_list = LIST_HEAD_INITIALIZER(tramp_info_page_list); @@ -69,6 +82,8 @@ static int get_trampoline(void *func, void *arg1, void *arg2, void *tramp_ptr) { goto out; } header = new_pages + _PAGE_SIZE * 2 - sizeof(*header); + header->magic = TRAMP_MAGIC; + header->version = TRAMP_VERSION; header->first_free = NULL; header->nfree = TRAMPOLINES_PER_PAGE; LIST_INSERT_HEAD(&tramp_free_page_list, header, free_pages); @@ -109,6 +124,14 @@ static void free_trampoline(void *tramp) { struct tramp_info_page_entry *entry = &entries[i]; struct tramp_info_page_header *header = page + 2 * _PAGE_SIZE - sizeof(*header); + if (header->magic != TRAMP_MAGIC) + panic("%s: bad pointer\n", __func__); + if (header->version != TRAMP_VERSION) { + /* shouldn't happen, but just in case multiple versions of this library + * are mixed up */ + return; + } + entry->next_free = header->first_free; header->first_free = entry; header->nfree++; @@ -16,8 +16,8 @@ #define TRAMPOLINE_SIZE 0x40 #endif #ifdef __LP64__ -#define REMAP_PAGE_ENTRY_SIZE 24 +#define TRAMP_INFO_PAGE_ENTRY_SIZE 24 #else -#define REMAP_PAGE_ENTRY_SIZE 12 +#define TRAMP_INFO_PAGE_ENTRY_SIZE 12 #endif #define TRAMPOLINES_PER_PAGE (_PAGE_SIZE / TRAMPOLINE_SIZE) |