58 lines
1.6 KiB
Diff
58 lines
1.6 KiB
Diff
commit 0df2ea0956e46f3914be01aa9d7b20a06d805e53
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Author: Emery Hemingway <ehmry@posteo.net>
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Date: Wed Apr 8 12:39:44 2020 +0530
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cxx: align exception allocator to sixteen bytes
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diff --git a/repos/base/src/lib/cxx/malloc_free.cc b/repos/base/src/lib/cxx/malloc_free.cc
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index b551dfe627..870dbb6c6d 100644
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--- a/repos/base/src/lib/cxx/malloc_free.cc
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+++ b/repos/base/src/lib/cxx/malloc_free.cc
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@@ -61,27 +61,23 @@ void Genode::init_cxx_heap(Env &env)
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}
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-typedef unsigned long Block_header;
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+typedef size_t Block_header;
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extern "C" void *malloc(size_t size)
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{
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- /* enforce size to be a multiple of 4 bytes */
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- size = (size + 3) & ~3;
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-
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/*
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- * We store the size of the allocation at the very
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- * beginning of the allocated block and return
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- * the subsequent address. This way, we can retrieve
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- * the size information when freeing the block.
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+ * We pad each allocation with 16 leading bytes for
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+ * storing the size of the allocation. This way, we can
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+ * retrieve the size information when freeing the block.
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*/
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- unsigned long real_size = size + sizeof(Block_header);
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- void *addr = 0;
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- if (!cxx_heap().alloc(real_size, &addr))
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- return 0;
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+ size_t real_size = size + 16;
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+ addr_t real_addr = 0;
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+ if (!cxx_heap().alloc(real_size, (void**)&real_addr))
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+ return nullptr;
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- *(Block_header *)addr = real_size;
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- return (Block_header *)addr + 1;
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+ *(Block_header *)real_addr = real_size;
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+ return (void*)(real_addr + 16);
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}
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@@ -101,7 +97,7 @@ extern "C" void free(void *ptr)
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{
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if (!ptr) return;
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- unsigned long *addr = ((unsigned long *)ptr) - 1;
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+ unsigned long *addr = (unsigned long *)(addr_t(ptr) - 16);
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cxx_heap().free(addr, *addr);
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}
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