[PATCH] x86/efi: Don't unmap EFI boot services code/data regions for EFI_OLD_MEMMAP and EFI_MIXED_MODE
Commit d5052a7130a6 ("x86/efi: Unmap EFI boot services code/data regions
from efi_pgd") forgets to take two EFI modes into consideration namely
EFI_OLD_MEMMAP and EFI_MIXED_MODE.
EFI_OLD_MEMMAP is a legacy way of mapping EFI regions into swapper_pg_dir
using ioremap() and init_memory_mapping(). This feature can be enabled by
passing "efi=old_map" as kernel command line argument. But,
efi_unmap_pages() unmaps EFI boot services code/data regions *only* from
efi_pgd and hence cannot be used for unmapping EFI boot services code/data
regions from swapper_pg_dir.
Introduce a temporary fix to not unmap EFI boot services code/data regions
when EFI_OLD_MEMMAP is enabled while working on a real fix.
EFI_MIXED_MODE is another feature where a 64-bit kernel runs on a
64-bit platform crippled by a 32-bit firmware. To support EFI_MIXED_MODE,
all RAM (i.e. namely EFI regions like EFI_CONVENTIONAL_MEMORY,
EFI_LOADER_, EFI_BOOT_SERVICES_ and
EFI_RUNTIME_CODE/DATA regions) is mapped into efi_pgd all the time to
facilitate EFI runtime calls access it's arguments in 1:1 mode. Hence,
don't unmap EFI boot services code/data regions when booted in mixed mode.
Signed-off-by: Sai Praneeth Prakhya
Cc: Borislav Petkov
Cc: Ingo Molnar
Cc: Andy Lutomirski
Cc: Dave Hansen
Cc: Bhupesh Sharma
Cc: Peter Zijlstra
Cc: Thomas Gleixner
Cc: Ard Biesheuvel
---
arch/x86/platform/efi/quirks.c | 16
1 file changed, 16 insertions(+)
diff --git a/arch/x86/platform/efi/quirks.c b/arch/x86/platform/efi/quirks.c
index 09e811b9da26..9c34230aaeae 100644
--- a/arch/x86/platform/efi/quirks.c
+++ b/arch/x86/platform/efi/quirks.c
@@ -380,6 +380,22 @@ static void __init efi_unmap_pages(efi_memory_desc_t *md)
u64 pa = md->phys_addr;
u64 va = md->virt_addr;
+ /*
+* To Do: Remove this check after adding functionality to unmap EFI boot
+* services code/data regions from direct mapping area because
+* "efi=old_map" maps EFI regions in swapper_pg_dir.
+*/
+ if (efi_enabled(EFI_OLD_MEMMAP))
+ return;
+
+ /*
+* EFI mixed mode has all RAM mapped to access arguments while making
+* EFI runtime calls, hence don't unmap EFI boot services code/data
+* regions.
+*/
+ if (!efi_is_native() && IS_ENABLED(CONFIG_EFI_MIXED))
+ return;
+
if (kernel_unmap_pages_in_pgd(pgd, pa, md->num_pages))
pr_err("Failed to unmap 1:1 mapping for 0x%llx\n", pa);
--
2.19.1
Re: [PATCH] pstore: Convert buf_lock to semaphore
On Tue, 4 Dec 2018 at 19:06, Sebastian Andrzej Siewior wrote: > > On 2018-12-04 09:23:13 [-0800], Kees Cook wrote: > > Okay, so, if kmsg_dump() uses rcu_read_lock(), that means efi-pstore > > can _never_ sleep, and it's nothing to do with pstore internals. :( I > > guess we just hard-code it, then? And efi-pstore should probably only > > attach to pstore if it has a nonblock implementation (and warn if one > > isn't available). > > I was about to suggest that. I am not aware if anything else could use > efi_pstore_write() use that but otherwise you could hardcode it. > efivar_entry_set_safe() will only use the default backend if no non-blocking variant is provided, in which case it assumes that the default one is non-blocking. Perhaps we should just assign both function pointers to the same function in this case.
Re: [PATCH efi-urgent] Revert "efi: Align 'efi_guid_t' to 64 bits"
On Fri, 21 Dec 2018 at 13:13, Borislav Petkov 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
> > Cc: Ingo Molnar
> > Cc: Andy Lutomirski
> > Cc: Borislav Petkov
> > Cc: Dave Hansen
> > Cc: H. Peter Anvin
> > Cc: Linus Torvalds
> > Cc: Peter Zijlstra
> > Cc: Qian Cai
> > Cc: Rik van Riel
> > Cc: Thomas Gleixner
> > Signed-off-by: Ard Biesheuvel
> > ---
> > 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
Re: [PATCH efi-urgent] Revert "efi: Align 'efi_guid_t' to 64 bits"
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
> Cc: Ingo Molnar
> Cc: Andy Lutomirski
> Cc: Borislav Petkov
> Cc: Dave Hansen
> Cc: H. Peter Anvin
> Cc: Linus Torvalds
> Cc: Peter Zijlstra
> Cc: Qian Cai
> Cc: Rik van Riel
> Cc: Thomas Gleixner
> Signed-off-by: Ard Biesheuvel
> ---
> 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.
[PATCH efi-urgent] Revert "efi: Align 'efi_guid_t' to 64 bits"
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
Cc: Ingo Molnar
Cc: Andy Lutomirski
Cc: Borislav Petkov
Cc: Dave Hansen
Cc: H. Peter Anvin
Cc: Linus Torvalds
Cc: Peter Zijlstra
Cc: Qian Cai
Cc: Rik van Riel
Cc: Thomas Gleixner
Signed-off-by: Ard Biesheuvel
---
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)
--
2.19.2
