diff mbox series

[efi-urgent] Revert "efi: Align 'efi_guid_t' to 64 bits"

Message ID 20181221115446.2670-1-ard.biesheuvel@linaro.org
State New
Headers show
Series [efi-urgent] Revert "efi: Align 'efi_guid_t' to 64 bits" | expand

Commit Message

Ard Biesheuvel Dec. 21, 2018, 11:54 a.m. UTC
This reverts commit 793423cf07e51e3185b8680167115813589c057d.

The 64-bit alignment affects the size of efi_config_table_32_t,
which is used as an array type. On the other hand, the former
byte alignment could trigger alignment faults during firmware
calls on 32-bit ARM, since UEFI defines efi_guid_t as a struct
of UINT32 + UINT16 + UINT16 + UINT8[8], and so it may use load/
store multiple instructions [requiring 32-bit alignment], e.g.,
on GUID pointers passed as function arguments since UEFI's view
of the type has implicit 32-bit alignment.

Let's sort this out for the next release, and revert the change
for now.

Fixes: 793423cf07e5 ("efi: Align 'efi_guid_t' to 64 bits")
Reported-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Qian Cai <cai@gmx.us>
Cc: Rik van Riel <riel@surriel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>

---
 include/linux/efi.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

-- 
2.19.2

Comments

Borislav Petkov Dec. 21, 2018, 12:13 p.m. UTC | #1
On Fri, Dec 21, 2018 at 12:54:46PM +0100, Ard Biesheuvel wrote:
> This reverts commit 793423cf07e51e3185b8680167115813589c057d.

> 

> The 64-bit alignment affects the size of efi_config_table_32_t,

> which is used as an array type. On the other hand, the former

> byte alignment could trigger alignment faults during firmware

> calls on 32-bit ARM, since UEFI defines efi_guid_t as a struct

> of UINT32 + UINT16 + UINT16 + UINT8[8], and so it may use load/

> store multiple instructions [requiring 32-bit alignment], e.g.,

> on GUID pointers passed as function arguments since UEFI's view

> of the type has implicit 32-bit alignment.

> 

> Let's sort this out for the next release, and revert the change

> for now.

> 

> Fixes: 793423cf07e5 ("efi: Align 'efi_guid_t' to 64 bits")

> Reported-by: Heinrich Schuchardt <xypron.glpk@gmx.de>

> Cc: Ingo Molnar <mingo@kernel.org>

> Cc: Andy Lutomirski <luto@kernel.org>

> Cc: Borislav Petkov <bp@alien8.de>

> Cc: Dave Hansen <dave.hansen@linux.intel.com>

> Cc: H. Peter Anvin <hpa@zytor.com>

> Cc: Linus Torvalds <torvalds@linux-foundation.org>

> Cc: Peter Zijlstra <peterz@infradead.org>

> Cc: Qian Cai <cai@gmx.us>

> Cc: Rik van Riel <riel@surriel.com>

> Cc: Thomas Gleixner <tglx@linutronix.de>

> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>

> ---

>  include/linux/efi.h | 2 +-

>  1 file changed, 1 insertion(+), 1 deletion(-)

> 

> diff --git a/include/linux/efi.h b/include/linux/efi.h

> index e6480c805932..100ce4a4aff6 100644

> --- a/include/linux/efi.h

> +++ b/include/linux/efi.h

> @@ -48,7 +48,7 @@ typedef u16 efi_char16_t;		/* UNICODE character */

>  typedef u64 efi_physical_addr_t;

>  typedef void *efi_handle_t;

>  

> -typedef guid_t efi_guid_t __aligned(8);

> +typedef guid_t efi_guid_t;

>  

>  #define EFI_GUID(a,b,c,d0,d1,d2,d3,d4,d5,d6,d7) \

>  	GUID_INIT(a, b, c, d0, d1, d2, d3, d4, d5, d6, d7)

> -- 


It was the top commit on tip:efi/urgent so I've zapped it.

HTH.

-- 
Regards/Gruss,
    Boris.

Good mailing practices for 400: avoid top-posting and trim the reply.
Ard Biesheuvel Dec. 21, 2018, 12:16 p.m. UTC | #2
On Fri, 21 Dec 2018 at 13:13, Borislav Petkov <bp@alien8.de> wrote:
>

> On Fri, Dec 21, 2018 at 12:54:46PM +0100, Ard Biesheuvel wrote:

> > This reverts commit 793423cf07e51e3185b8680167115813589c057d.

> >

> > The 64-bit alignment affects the size of efi_config_table_32_t,

> > which is used as an array type. On the other hand, the former

> > byte alignment could trigger alignment faults during firmware

> > calls on 32-bit ARM, since UEFI defines efi_guid_t as a struct

> > of UINT32 + UINT16 + UINT16 + UINT8[8], and so it may use load/

> > store multiple instructions [requiring 32-bit alignment], e.g.,

> > on GUID pointers passed as function arguments since UEFI's view

> > of the type has implicit 32-bit alignment.

> >

> > Let's sort this out for the next release, and revert the change

> > for now.

> >

> > Fixes: 793423cf07e5 ("efi: Align 'efi_guid_t' to 64 bits")

> > Reported-by: Heinrich Schuchardt <xypron.glpk@gmx.de>

> > Cc: Ingo Molnar <mingo@kernel.org>

> > Cc: Andy Lutomirski <luto@kernel.org>

> > Cc: Borislav Petkov <bp@alien8.de>

> > Cc: Dave Hansen <dave.hansen@linux.intel.com>

> > Cc: H. Peter Anvin <hpa@zytor.com>

> > Cc: Linus Torvalds <torvalds@linux-foundation.org>

> > Cc: Peter Zijlstra <peterz@infradead.org>

> > Cc: Qian Cai <cai@gmx.us>

> > Cc: Rik van Riel <riel@surriel.com>

> > Cc: Thomas Gleixner <tglx@linutronix.de>

> > Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>

> > ---

> >  include/linux/efi.h | 2 +-

> >  1 file changed, 1 insertion(+), 1 deletion(-)

> >

> > diff --git a/include/linux/efi.h b/include/linux/efi.h

> > index e6480c805932..100ce4a4aff6 100644

> > --- a/include/linux/efi.h

> > +++ b/include/linux/efi.h

> > @@ -48,7 +48,7 @@ typedef u16 efi_char16_t;           /* UNICODE character */

> >  typedef u64 efi_physical_addr_t;

> >  typedef void *efi_handle_t;

> >

> > -typedef guid_t efi_guid_t __aligned(8);

> > +typedef guid_t efi_guid_t;

> >

> >  #define EFI_GUID(a,b,c,d0,d1,d2,d3,d4,d5,d6,d7) \

> >       GUID_INIT(a, b, c, d0, d1, d2, d3, d4, d5, d6, d7)

> > --

>

> It was the top commit on tip:efi/urgent so I've zapped it.

>


Even better!

Thanks a lot
diff mbox series

Patch

diff --git a/include/linux/efi.h b/include/linux/efi.h
index e6480c805932..100ce4a4aff6 100644
--- a/include/linux/efi.h
+++ b/include/linux/efi.h
@@ -48,7 +48,7 @@  typedef u16 efi_char16_t;		/* UNICODE character */
 typedef u64 efi_physical_addr_t;
 typedef void *efi_handle_t;
 
-typedef guid_t efi_guid_t __aligned(8);
+typedef guid_t efi_guid_t;
 
 #define EFI_GUID(a,b,c,d0,d1,d2,d3,d4,d5,d6,d7) \
 	GUID_INIT(a, b, c, d0, d1, d2, d3, d4, d5, d6, d7)