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diff --git a/stand/efi/loader/bootinfo.c b/stand/efi/loader/bootinfo.c
--- a/stand/efi/loader/bootinfo.c
+++ b/stand/efi/loader/bootinfo.c
@@ -232,52 +232,59 @@
* the memory map are caused by splitting a range of free
* memory into two, so that one is marked as being loader
* data.
+ *
+ * Perform the allocation before the ExitBootServices retry
+ * loop so that no boot service calls (AllocatePages,
+ * FreePages) are made between GetMemoryMap and
+ * ExitBootServices. The UEFI specification (s7.4.6) requires
+ * that the memory map key passed to ExitBootServices match
+ * the current map; calling any boot service in between may
+ * invalidate the key. This matches the pre-allocation
+ * strategy used by the Linux EFI stub.
*/
-
sz = 0;
- mm = NULL;
+ status = BS->GetMemoryMap(&sz, NULL, &efi_mapkey, &dsz, &mmver);
+ if (status != EFI_BUFFER_TOO_SMALL) {
+ printf("%s: GetMemoryMap error %lu\n", __func__,
+ DECODE_ERROR(status));
+ return (EINVAL);
+ }
+ sz += (10 * dsz);
+ pages = EFI_SIZE_TO_PAGES(sz + efisz);
+ status = BS->AllocatePages(AllocateAnyPages, EfiLoaderData,
+ pages, &addr);
+ if (EFI_ERROR(status)) {
+ printf("%s: AllocatePages error %lu\n", __func__,
+ DECODE_ERROR(status));
+ return (ENOMEM);
+ }
+
+ /*
+ * Read the memory map and stash it after bootinfo. Align the
+ * memory map on a 16-byte boundary (the bootinfo block is page
+ * aligned).
+ */
+ efihdr = (struct efi_map_header *)(uintptr_t)addr;
+ mm = (void *)((uint8_t *)efihdr + efisz);
/*
* Matthew Garrett has observed at least one system changing the
- * memory map when calling ExitBootServices, causing it to return an
- * error, probably because callbacks are allocating memory.
- * So we need to retry calling it at least once.
+ * memory map when calling ExitBootServices, causing it to return
+ * an error, probably because EBS event handlers allocate memory.
+ *
+ * The retry loop must not call any boot services between
+ * GetMemoryMap and ExitBootServices. Any boot service call
+ * (including printf/OutputString) can invalidate the memory
+ * map key, and the spec requires the key to be current.
*/
for (retry = 2; retry > 0; retry--) {
- for (;;) {
- status = BS->GetMemoryMap(&sz, mm, &efi_mapkey, &dsz, &mmver);
- if (!EFI_ERROR(status))
- break;
-
- if (status != EFI_BUFFER_TOO_SMALL) {
- printf("%s: GetMemoryMap error %lu\n", __func__,
- DECODE_ERROR(status));
- return (EINVAL);
- }
-
- if (addr != 0)
- BS->FreePages(addr, pages);
-
- /* Add 10 descriptors to the size to allow for
- * fragmentation caused by calling AllocatePages */
- sz += (10 * dsz);
- pages = EFI_SIZE_TO_PAGES(sz + efisz);
- status = BS->AllocatePages(AllocateAnyPages, EfiLoaderData,
- pages, &addr);
- if (EFI_ERROR(status)) {
- printf("%s: AllocatePages error %lu\n", __func__,
- DECODE_ERROR(status));
- return (ENOMEM);
- }
-
- /*
- * Read the memory map and stash it after bootinfo. Align the
- * memory map on a 16-byte boundary (the bootinfo block is page
- * aligned).
- */
- efihdr = (struct efi_map_header *)(uintptr_t)addr;
- mm = (void *)((uint8_t *)efihdr + efisz);
- sz = (EFI_PAGE_SIZE * pages) - efisz;
+ sz = (EFI_PAGE_SIZE * pages) - efisz;
+ status = BS->GetMemoryMap(&sz, mm, &efi_mapkey, &dsz, &mmver);
+ if (EFI_ERROR(status)) {
+ BS->FreePages(addr, pages);
+ printf("%s: GetMemoryMap error %lu\n", __func__,
+ DECODE_ERROR(status));
+ return (EINVAL);
}
if (!exit_bs)

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