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efi_loader: fix bug in efi_get_memory_map

PATCH Applied Rob Clark 3 participants 5 messages Jul 26, 2017 – Jul 28, 2017

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Rob Clark

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#0 lore raw

PATCH 1/1 efi_loader: fix bug in efi_get_memory_map

When booting shim -> fallback -> shim -> grub -> linux the memory map is a bit larger than the size linux passes in on the first call. But in the EFI_BUFFER_TOO_SMALL case we were not passing back the updated size to linux so it would loop forever.

Signed-off-by Rob Clark <[email protected]>
---
 lib/efi_loader/efi_memory.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
lib/efi_loader/efi_memory.c +2 -2
index f59e3ea327..9e079f1fa3 100644
@@ -407,11 +407,11 @@ efi_status_t efi_get_memory_map(unsigned long *memory_map_size,
 
 	map_size = map_entries * sizeof(struct efi_mem_desc);
 
+	*memory_map_size = map_size;
+
 	if (provided_map_size < map_size)
 		return EFI_BUFFER_TOO_SMALL;
 
-	*memory_map_size = map_size;
-
 	if (descriptor_size)
 		*descriptor_size = sizeof(struct efi_mem_desc);
Signature · 1 line
2.13.0
#1 lore raw

PATCH 1/1 efi_loader: fix bug in efi_get_memory_map

Quoted 6 lines · Rob Clark

When booting shim -> fallback -> shim -> grub -> linux the memory map is a bit larger than the size linux passes in on the first call. But in the EFI_BUFFER_TOO_SMALL case we were not passing back the updated size to linux so it would loop forever.

Signed-off-by Rob Clark <[email protected]>

The spec is actually very explicit about this case. It says in the EFI_BUFFER_TOO_SMALL case, we *have* to return the map size.

Alex

author
#2 lore raw

PATCH 1/1 efi_loader: fix bug in efi_get_memory_map

Quoted 9 lines · Alexander Graf
Quoted 6 lines · Rob Clark

When booting shim -> fallback -> shim -> grub -> linux the memory map is a bit larger than the size linux passes in on the first call. But in the EFI_BUFFER_TOO_SMALL case we were not passing back the updated size to linux so it would loop forever.

Quoted 6 lines
Quoted 1 line
Signed-off-by Rob Clark <[email protected]>

The spec is actually very explicit about this case. It says in the EFI_BUFFER_TOO_SMALL case, we *have* to return the map size.

yes, that is what I fixed. We *weren't* returning the required buffer size before :-)

BR,
-R

#3 lore raw

PATCH 1/1 efi_loader: fix bug in efi_get_memory_map

Quoted 7 lines · On Mittwoch, 26. Juli 2017 22:25:29 CEST Rob Clark wrote:
Quoted 6 lines · Alexander Graf
Quoted 5 lines · Rob Clark

When booting shim -> fallback -> shim -> grub -> linux the memory map is a bit larger than the size linux passes in on the first call. But in the EFI_BUFFER_TOO_SMALL case we were not passing back the updated size to linux so it would loop forever.

Quoted 7 lines
Quoted 4 lines
Quoted 1 line
Signed-off-by Rob Clark <[email protected]>

The spec is actually very explicit about this case. It says in the EFI_BUFFER_TOO_SMALL case, we *have* to return the map size.

yes, that is what I fixed. We *weren't* returning the required buffer size before :-)

Sigh, yes, this was correct in the first 3 versions of the patch series, but unfortunately broken in v4 which was actually committed ...

See: https://lists.denx.de/pipermail/u-boot/2016-October/268766.html

Actually, the map_size variable is no longer needed, if you assign to *memory_map_size directly.

Anyway, this patch is:

Reviewed-by Stefan Brüns <[email protected]>

Kind regards,

Stefan

Applied
#4 lore raw
In reply to Rob Clark
Quoted 6 lines

When booting shim -> fallback -> shim -> grub -> linux the memory map is a bit larger than the size linux passes in on the first call. But in the EFI_BUFFER_TOO_SMALL case we were not passing back the updated size to linux so it would loop forever.

Signed-off-by Rob Clark <[email protected]>

Thanks, applied to efi-next

Alex