Commit d2078d5adbe2 ("x86: EFI stub support for large memory maps")
added support for EFI memory maps larger than 128 entries. Following
allocation for this new buffer (within the exit_boot function calling
alloc_e820ext) another call to efi_get_memory_map was performed.
This took place before the final call to ExitBootServices (EBS) to
insure the memory map buffer was large enough since memory allocation
is not allowed after calling EBS.
Later this code was refactored and portions were added to
efi-stub-helper.c. The call to efi_get_memory_map did not remain after
calling alloc_e820ext. In a later patch, a new EFI_MMAP_NR_SLACK_SLOTS was
introduced to help give some headroom should the memory map grow after
the EBS is called. This does not alway provide enough space with large
memory maps.
This change will call efi_get_memory_map one final time before calling EBS,
ensuring there is enough room for the memory map buffer. The additional
headroom will be left alone for any memory change that may currently
be in flight between the final efi_get_memory_map call and EBS.
Signed-off-by: Eric Snowberg <eric.snowberg@xxxxxxxxxx>
---
drivers/firmware/efi/libstub/efi-stub-helper.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/drivers/firmware/efi/libstub/efi-stub-helper.c b/drivers/firmware/efi/libstub/efi-stub-helper.c
index b018436..3363b4e 100644
--- a/drivers/firmware/efi/libstub/efi-stub-helper.c
+++ b/drivers/firmware/efi/libstub/efi-stub-helper.c
@@ -845,6 +845,14 @@ efi_status_t efi_exit_boot_services(efi_system_table_t *sys_table_arg,
if (status != EFI_SUCCESS)
goto free_map;
+ /*
+ * priv_func could have allocated memory, thus call efi_get_memory_map
+ * one more time.
+ */
+ status = efi_get_memory_map(sys_table_arg, map);
+ if (status != EFI_SUCCESS)
+ goto fail;
+
status = efi_call_early(exit_boot_services, handle, *map->key_ptr);
if (status == EFI_INVALID_PARAMETER) {
--
1.8.3.1
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