[tip:x86/urgent] x86/platform/UV: Fix support for EFI_OLD_MEMMAP after BIOS callback updates

[tip-bot for Alex Thorlton]

Commit-ID:  caef78b6cdeddf4ad364f95910bba6b43b8eb9bf
Gitweb: http://git.kernel.org/tip/caef78b6cdeddf4ad364f95910bba6b43b8eb9bf
Author: Alex Thorlton 
AuthorDate: Wed, 19 Oct 2016 20:48:51 -0500
Committer:  Ingo Molnar 
CommitDate: Thu, 20 Oct 2016 08:47:58 +0200

x86/platform/UV: Fix support for EFI_OLD_MEMMAP after BIOS callback updates

Some time ago, we brought our UV BIOS callback code up to speed with the
new EFI memory mapping scheme, in commit:

d1be84a232e3 ("x86/uv: Update uv_bios_call() to use 
efi_call_virt_pointer()")

By leveraging some changes that I made to a few of the EFI runtime
callback mechanisms, in commit:

80e75596079f ("efi: Convert efi_call_virt() to efi_call_virt_pointer()")

This got everything running smoothly on UV, with the new EFI mapping
code.  However, this left one, small loose end, in that EFI_OLD_MEMMAP
(a.k.a. efi=old_map) will no longer work on UV, on kernels that include
the aforementioned changes.

At the time this was not a major issue (in fact, it still really isn't),
but there's no reason that EFI_OLD_MEMMAP *shouldn't* work on our
systems.  This commit adds a check into uv_bios_call(), to see if we have
the EFI_OLD_MEMMAP bit set in efi.flags.  If it is set, we fall back to
using our old callback method, which uses efi_call() directly on the __va()
of our function pointer.

Signed-off-by: Alex Thorlton 
Acked-by: Matt Fleming 
Cc:  # v4.7 and later
Cc: Andy Lutomirski 
Cc: Ard Biesheuvel 
Cc: Borislav Petkov 
Cc: Brian Gerst 
Cc: Denys Vlasenko 
Cc: Dimitri Sivanich 
Cc: H. Peter Anvin 
Cc: Josh Poimboeuf 
Cc: Linus Torvalds 
Cc: Masahiro Yamada 
Cc: Mike Travis 
Cc: Peter Zijlstra 
Cc: Russ Anderson 
Cc: Thomas Gleixner 
Cc: linux-...@vger.kernel.org
Link: 
http://lkml.kernel.org/r/1476928131-170101-1-git-send-email-athorl...@sgi.com
Signed-off-by: Ingo Molnar 
---
 arch/x86/platform/uv/bios_uv.c | 10 +-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/arch/x86/platform/uv/bios_uv.c b/arch/x86/platform/uv/bios_uv.c
index b4d5e95..4a6a5a2 100644
--- a/arch/x86/platform/uv/bios_uv.c
+++ b/arch/x86/platform/uv/bios_uv.c
@@ -40,7 +40,15 @@ s64 uv_bios_call(enum uv_bios_cmd which, u64 a1, u64 a2, u64 
a3, u64 a4, u64 a5)
 */
return BIOS_STATUS_UNIMPLEMENTED;
 
-   ret = efi_call_virt_pointer(tab, function, (u64)which, a1, a2, a3, a4, 
a5);
+   /*
+* If EFI_OLD_MEMMAP is set, we need to fall back to using our old EFI
+* callback method, which uses efi_call() directly, with the kernel 
page tables:
+*/
+   if (unlikely(test_bit(EFI_OLD_MEMMAP, )))
+   ret = efi_call((void *)__va(tab->function), (u64)which, a1, a2, 
a3, a4, a5);
+   else
+   ret = efi_call_virt_pointer(tab, function, (u64)which, a1, a2, 
a3, a4, a5);
+
return ret;
 }
 EXPORT_SYMBOL_GPL(uv_bios_call);

[tip:x86/urgent] x86/platform/UV: Fix support for EFI_OLD_MEMMAP after BIOS callback updates

[tip-bot for Alex Thorlton]

Commit-ID:  caef78b6cdeddf4ad364f95910bba6b43b8eb9bf
Gitweb: http://git.kernel.org/tip/caef78b6cdeddf4ad364f95910bba6b43b8eb9bf
Author: Alex Thorlton 
AuthorDate: Wed, 19 Oct 2016 20:48:51 -0500
Committer:  Ingo Molnar 
CommitDate: Thu, 20 Oct 2016 08:47:58 +0200

x86/platform/UV: Fix support for EFI_OLD_MEMMAP after BIOS callback updates

Some time ago, we brought our UV BIOS callback code up to speed with the
new EFI memory mapping scheme, in commit:

d1be84a232e3 ("x86/uv: Update uv_bios_call() to use 
efi_call_virt_pointer()")

By leveraging some changes that I made to a few of the EFI runtime
callback mechanisms, in commit:

80e75596079f ("efi: Convert efi_call_virt() to efi_call_virt_pointer()")

This got everything running smoothly on UV, with the new EFI mapping
code.  However, this left one, small loose end, in that EFI_OLD_MEMMAP
(a.k.a. efi=old_map) will no longer work on UV, on kernels that include
the aforementioned changes.

At the time this was not a major issue (in fact, it still really isn't),
but there's no reason that EFI_OLD_MEMMAP *shouldn't* work on our
systems.  This commit adds a check into uv_bios_call(), to see if we have
the EFI_OLD_MEMMAP bit set in efi.flags.  If it is set, we fall back to
using our old callback method, which uses efi_call() directly on the __va()
of our function pointer.

Signed-off-by: Alex Thorlton 
Acked-by: Matt Fleming 
Cc:  # v4.7 and later
Cc: Andy Lutomirski 
Cc: Ard Biesheuvel 
Cc: Borislav Petkov 
Cc: Brian Gerst 
Cc: Denys Vlasenko 
Cc: Dimitri Sivanich 
Cc: H. Peter Anvin 
Cc: Josh Poimboeuf 
Cc: Linus Torvalds 
Cc: Masahiro Yamada 
Cc: Mike Travis 
Cc: Peter Zijlstra 
Cc: Russ Anderson 
Cc: Thomas Gleixner 
Cc: linux-...@vger.kernel.org
Link: 
http://lkml.kernel.org/r/1476928131-170101-1-git-send-email-athorl...@sgi.com
Signed-off-by: Ingo Molnar 
---
 arch/x86/platform/uv/bios_uv.c | 10 +-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/arch/x86/platform/uv/bios_uv.c b/arch/x86/platform/uv/bios_uv.c
index b4d5e95..4a6a5a2 100644
--- a/arch/x86/platform/uv/bios_uv.c
+++ b/arch/x86/platform/uv/bios_uv.c
@@ -40,7 +40,15 @@ s64 uv_bios_call(enum uv_bios_cmd which, u64 a1, u64 a2, u64 
a3, u64 a4, u64 a5)
 */
return BIOS_STATUS_UNIMPLEMENTED;
 
-   ret = efi_call_virt_pointer(tab, function, (u64)which, a1, a2, a3, a4, 
a5);
+   /*
+* If EFI_OLD_MEMMAP is set, we need to fall back to using our old EFI
+* callback method, which uses efi_call() directly, with the kernel 
page tables:
+*/
+   if (unlikely(test_bit(EFI_OLD_MEMMAP, )))
+   ret = efi_call((void *)__va(tab->function), (u64)which, a1, a2, 
a3, a4, a5);
+   else
+   ret = efi_call_virt_pointer(tab, function, (u64)which, a1, a2, 
a3, a4, a5);
+
return ret;
 }
 EXPORT_SYMBOL_GPL(uv_bios_call);