129 lines
4 KiB
C
129 lines
4 KiB
C
/* integrity check (UMM_INTEGRITY_CHECK) {{{ */
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#ifdef UMM_INTEGRITY_CHECK
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#include <stdint.h>
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#include <stdbool.h>
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/*
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* Perform integrity check of the whole heap data. Returns 1 in case of
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* success, 0 otherwise.
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*
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* First of all, iterate through all free blocks, and check that all backlinks
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* match (i.e. if block X has next free block Y, then the block Y should have
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* previous free block set to X).
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*
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* Additionally, we check that each free block is correctly marked with
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* `UMM_FREELIST_MASK` on the `next` pointer: during iteration through free
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* list, we mark each free block by the same flag `UMM_FREELIST_MASK`, but
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* on `prev` pointer. We'll check and unmark it later.
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*
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* Then, we iterate through all blocks in the heap, and similarly check that
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* all backlinks match (i.e. if block X has next block Y, then the block Y
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* should have previous block set to X).
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*
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* But before checking each backlink, we check that the `next` and `prev`
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* pointers are both marked with `UMM_FREELIST_MASK`, or both unmarked.
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* This way, we ensure that the free flag is in sync with the free pointers
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* chain.
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*/
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bool umm_integrity_check(void) {
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bool ok = true;
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uint16_t prev;
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uint16_t cur;
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UMM_CHECK_INITIALIZED();
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/* Iterate through all free blocks */
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prev = 0;
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while (1) {
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cur = UMM_NFREE(prev);
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/* Check that next free block number is valid */
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if (cur >= UMM_NUMBLOCKS) {
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DBGLOG_CRITICAL("Heap integrity broken: too large next free num: %d "
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"(in block %d, addr 0x%08x)\n",
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cur, prev, DBGLOG_32_BIT_PTR(&UMM_NBLOCK(prev)));
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ok = false;
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goto clean;
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}
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if (cur == 0) {
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/* No more free blocks */
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break;
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}
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/* Check if prev free block number matches */
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if (UMM_PFREE(cur) != prev) {
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DBGLOG_CRITICAL("Heap integrity broken: free links don't match: "
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"%d -> %d, but %d -> %d\n",
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prev, cur, cur, UMM_PFREE(cur));
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ok = false;
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goto clean;
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}
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UMM_PBLOCK(cur) |= UMM_FREELIST_MASK;
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prev = cur;
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}
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/* Iterate through all blocks */
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prev = 0;
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while (1) {
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cur = UMM_NBLOCK(prev) & UMM_BLOCKNO_MASK;
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/* Check that next block number is valid */
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if (cur >= UMM_NUMBLOCKS) {
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DBGLOG_CRITICAL("Heap integrity broken: too large next block num: %d "
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"(in block %d, addr 0x%08x)\n",
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cur, prev, DBGLOG_32_BIT_PTR(&UMM_NBLOCK(prev)));
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ok = false;
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goto clean;
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}
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if (cur == 0) {
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/* No more blocks */
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break;
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}
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/* make sure the free mark is appropriate, and unmark it */
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if ((UMM_NBLOCK(cur) & UMM_FREELIST_MASK)
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!= (UMM_PBLOCK(cur) & UMM_FREELIST_MASK)) {
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DBGLOG_CRITICAL("Heap integrity broken: mask wrong at addr 0x%08x: n=0x%x, p=0x%x\n",
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DBGLOG_32_BIT_PTR(&UMM_NBLOCK(cur)),
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(UMM_NBLOCK(cur) & UMM_FREELIST_MASK),
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(UMM_PBLOCK(cur) & UMM_FREELIST_MASK));
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ok = false;
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goto clean;
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}
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/* make sure the block list is sequential */
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if (cur <= prev) {
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DBGLOG_CRITICAL("Heap integrity broken: next block %d is before prev this one "
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"(in block %d, addr 0x%08x)\n",
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cur, prev, DBGLOG_32_BIT_PTR(&UMM_NBLOCK(prev)));
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ok = false;
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goto clean;
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}
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/* unmark */
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UMM_PBLOCK(cur) &= UMM_BLOCKNO_MASK;
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/* Check if prev block number matches */
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if (UMM_PBLOCK(cur) != prev) {
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DBGLOG_CRITICAL("Heap integrity broken: block links don't match: "
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"%d -> %d, but %d -> %d\n",
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prev, cur, cur, UMM_PBLOCK(cur));
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ok = false;
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goto clean;
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}
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prev = cur;
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}
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clean:
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if (!ok) {
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UMM_HEAP_CORRUPTION_CB();
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}
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return ok;
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}
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#endif
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/* }}} */
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