Hi Ard,
On 23-06-18 23:19, Ard Biesheuvel wrote:
Commit 2c3625cb9fa2
efi/x86: Fold __setup_efi_pci32() and __setup_efi_pci64() into one function
merged the two versions of __setup_efi_pciXX(), without taking into
account that the 32-bit version used a rather dodgy trick to pass an
immediate 0 constant as argument for a uint64_t parameter.
The issue is caused by the fact that on x86, UEFI protocol method calls
are redirected via struct efi_config::call(), which is a variadic function,
and so the compiler has to infer the types of the parameters from the
arguments rather than from the prototype. As the 32-bit x86 calling
convention passes arguments via the stack, passing the unqualified
constant 0 twice is the same as passing 0ULL, which is why the 32-bit
code in __setup_efi_pci32() contained the following call:
status = efi_early->call(pci->attributes, pci,
EfiPciIoAttributeOperationGet, 0, 0,
&attributes);
to invoke this UEFI protocol method:
typedef
EFI_STATUS
(EFIAPI *EFI_PCI_IO_PROTOCOL_ATTRIBUTES) (
IN EFI_PCI_IO_PROTOCOL *This,
IN EFI_PCI_IO_PROTOCOL_ATTRIBUTE_OPERATION Operation,
IN UINT64 Attributes,
OUT UINT64 *Result OPTIONAL
);
After the merge, we inadvertently ended up with this version for both
32-bit and 64-bit builds, breaking the latter.
So replace the two zeroes with the explicitly typed constant 0ULL,
which works as expected on both 32-bit and 64-bit builds.
Reported-by: Wilfried Klaebe <linux-kernel@xxxxxxxxxxxxxxxxxxxxxxxxxx>
Tested-by: Wilfried Klaebe <linux-kernel@xxxxxxxxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
---
Wilfried tested the 64-bit build, and I checked the generated assembly
of a 32-bit build with and without this patch, and they are identical.
Ard, thank you for Cc-ing me on this.
I've tested a 64 bit kernel build on a 32 bit UEFI firmware (so mixed mode)
and this patch causes a reboot loop there. I do get grub (no surprise there
as grub is unchanged), but as soon as the kernel loads the device resets.
So I think we need some special casing there to deal with a 64 bit kernel
calling into 32 bit UEFI.
Regards,
Hans
Ingo, mind applying this directly? Thanks.
arch/x86/boot/compressed/eboot.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/boot/compressed/eboot.c b/arch/x86/boot/compressed/eboot.c
index a8a8642d2b0b..e57665b4ba1c 100644
--- a/arch/x86/boot/compressed/eboot.c
+++ b/arch/x86/boot/compressed/eboot.c
@@ -118,7 +118,7 @@ __setup_efi_pci(efi_pci_io_protocol_t *pci, struct pci_setup_rom **__rom)
void *romimage;
status = efi_call_proto(efi_pci_io_protocol, attributes, pci,
- EfiPciIoAttributeOperationGet, 0, 0,
+ EfiPciIoAttributeOperationGet, 0ULL,
&attributes);
if (status != EFI_SUCCESS)
return status;
--
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