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authorZach Bobroff <zacharyb@ami.com>2013-06-07 13:02:50 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-07-21 18:21:27 -0700
commit587562a77c7ab453d16f6b6bb02951bd66c44982 (patch)
treee64eb8d9ee9dcd78a593bec600674356e5165b2e
parenta2ebe4443fd55755cae5834e3f3021d3572cc463 (diff)
downloadvexpress-lsk-587562a77c7ab453d16f6b6bb02951bd66c44982.tar.gz
x86, efi: retry ExitBootServices() on failure
commit d3768d885c6ccbf8a137276843177d76c49033a7 upstream. ExitBootServices is absolutely supposed to return a failure if any ExitBootServices event handler changes the memory map. Basically the get_map loop should run again if ExitBootServices returns an error the first time. I would say it would be fair that if ExitBootServices gives an error the second time then Linux would be fine in returning control back to BIOS. The second change is the following line: again: size += sizeof(*mem_map) * 2; Originally you were incrementing it by the size of one memory map entry. The issue here is all related to the low_alloc routine you are using. In this routine you are making allocations to get the memory map itself. Doing this allocation or allocations can affect the memory map by more than one record. [ mfleming - changelog, code style ] Signed-off-by: Zach Bobroff <zacharyb@ami.com> Signed-off-by: Matt Fleming <matt.fleming@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--arch/x86/boot/compressed/eboot.c20
1 files changed, 17 insertions, 3 deletions
diff --git a/arch/x86/boot/compressed/eboot.c b/arch/x86/boot/compressed/eboot.c
index c205035a6b9..d606463aa6d 100644
--- a/arch/x86/boot/compressed/eboot.c
+++ b/arch/x86/boot/compressed/eboot.c
@@ -992,18 +992,20 @@ static efi_status_t exit_boot(struct boot_params *boot_params,
efi_memory_desc_t *mem_map;
efi_status_t status;
__u32 desc_version;
+ bool called_exit = false;
u8 nr_entries;
int i;
size = sizeof(*mem_map) * 32;
again:
- size += sizeof(*mem_map);
+ size += sizeof(*mem_map) * 2;
_size = size;
status = low_alloc(size, 1, (unsigned long *)&mem_map);
if (status != EFI_SUCCESS)
return status;
+get_map:
status = efi_call_phys5(sys_table->boottime->get_memory_map, &size,
mem_map, &key, &desc_size, &desc_version);
if (status == EFI_BUFFER_TOO_SMALL) {
@@ -1029,8 +1031,20 @@ again:
/* Might as well exit boot services now */
status = efi_call_phys2(sys_table->boottime->exit_boot_services,
handle, key);
- if (status != EFI_SUCCESS)
- goto free_mem_map;
+ if (status != EFI_SUCCESS) {
+ /*
+ * ExitBootServices() will fail if any of the event
+ * handlers change the memory map. In which case, we
+ * must be prepared to retry, but only once so that
+ * we're guaranteed to exit on repeated failures instead
+ * of spinning forever.
+ */
+ if (called_exit)
+ goto free_mem_map;
+
+ called_exit = true;
+ goto get_map;
+ }
/* Historic? */
boot_params->alt_mem_k = 32 * 1024;