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authorZach Bobroff <zacharyb@ami.com>2013-06-07 12:02:50 (GMT)
committerMatt Fleming <matt.fleming@intel.com>2013-06-11 06:51:54 (GMT)
commitd3768d885c6ccbf8a137276843177d76c49033a7 (patch)
treea50eb1b4b1b0ff59a55633562b7096bc091889af
parent43ab0476a648053e5998bf081f47f215375a4502 (diff)
downloadlinux-d3768d885c6ccbf8a137276843177d76c49033a7.tar.xz
x86, efi: retry ExitBootServices() on failure
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> Cc: <stable@vger.kernel.org> Signed-off-by: Matt Fleming <matt.fleming@intel.com>
-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 35ee62f..7c6e5d9 100644
--- a/arch/x86/boot/compressed/eboot.c
+++ b/arch/x86/boot/compressed/eboot.c
@@ -1037,18 +1037,20 @@ 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) {
@@ -1074,8 +1076,20 @@ 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;