From: Matt Fleming <matt-HNK1S37rvNbeXh+fF434Mdi2O/JbrIOy@public.gmane.org>
To: linux-efi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Cc: "H. Peter Anvin" <hpa-YMNOUZJC4hwAvxtiuMwx3w@public.gmane.org>,
Borislav Petkov <bp-Gina5bIWoIWzQB+pC5nmwQ@public.gmane.org>,
Alan Cox <alan-qBU/x9rampVanCEyBjwyrvXRex20P6io@public.gmane.org>,
Matthew Garrett <mjg59-1xO5oi07KQx4cg9Nei1l7Q@public.gmane.org>,
Matt Fleming
<matt.fleming-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
Subject: [PATCH 12/13] x86/boot: Don't overwrite cr4 when enabling PAE
Date: Thu, 27 Feb 2014 19:50:59 +0000 [thread overview]
Message-ID: <1393530660-12692-13-git-send-email-matt@console-pimps.org> (raw)
In-Reply-To: <1393530660-12692-1-git-send-email-matt-HNK1S37rvNbeXh+fF434Mdi2O/JbrIOy@public.gmane.org>
From: Matt Fleming <matt.fleming-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
Some EFI firmware makes use of the FPU during boottime services and
clearing X86_CR4_OSFXSR by overwriting %cr4 causes the firmware to
crash.
Add the PAE bit explicitly instead of trashing the existing contents,
leaving the rest of the bits as the firmware set them.
Cc: H. Peter Anvin <hpa-YMNOUZJC4hwAvxtiuMwx3w@public.gmane.org>
Signed-off-by: Matt Fleming <matt.fleming-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
---
arch/x86/boot/compressed/head_64.S | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/arch/x86/boot/compressed/head_64.S b/arch/x86/boot/compressed/head_64.S
index 37c741b0d2ac..4f40cddd025d 100644
--- a/arch/x86/boot/compressed/head_64.S
+++ b/arch/x86/boot/compressed/head_64.S
@@ -113,7 +113,8 @@ ENTRY(startup_32)
lgdt gdt(%ebp)
/* Enable PAE mode */
- movl $(X86_CR4_PAE), %eax
+ movl %cr4, %eax
+ orl $X86_CR4_PAE, %eax
movl %eax, %cr4
/*
--
1.8.5.3
next prev parent reply other threads:[~2014-02-27 19:50 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-02-27 19:50 [PATCH 00/13] EFI mixed mode Matt Fleming
[not found] ` <1393530660-12692-1-git-send-email-matt-HNK1S37rvNbeXh+fF434Mdi2O/JbrIOy@public.gmane.org>
2014-02-27 19:50 ` [PATCH 01/13] x86/boot: Cleanup header.S by removing some #ifdefs Matt Fleming
2014-02-27 19:50 ` [PATCH 02/13] x86, tools: Consolidate #ifdef code Matt Fleming
2014-02-27 19:50 ` [PATCH 03/13] x86/mm/pageattr: Always dump the right page table in an oops Matt Fleming
2014-02-27 19:50 ` [PATCH 04/13] x86/efi: Delete dead code when checking for non-native Matt Fleming
2014-02-27 19:50 ` [PATCH 05/13] efi: Add separate 32-bit/64-bit definitions Matt Fleming
2014-02-27 19:50 ` [PATCH 06/13] x86/efi: Build our own EFI services pointer table Matt Fleming
[not found] ` <1393530660-12692-7-git-send-email-matt-HNK1S37rvNbeXh+fF434Mdi2O/JbrIOy@public.gmane.org>
2014-02-27 20:09 ` H. Peter Anvin
[not found] ` <530F9B71.1030405-YMNOUZJC4hwAvxtiuMwx3w@public.gmane.org>
2014-02-28 14:12 ` Matt Fleming
[not found] ` <20140228141206.GA17881-HNK1S37rvNbeXh+fF434Mdi2O/JbrIOy@public.gmane.org>
2014-02-28 15:14 ` H. Peter Anvin
2014-02-27 19:50 ` [PATCH 07/13] x86/efi: Add early thunk code to go from 64-bit to 32-bit Matt Fleming
2014-02-27 19:50 ` [PATCH 08/13] x86/efi: Split the boot stub into 32/64 code paths Matt Fleming
2014-02-27 19:50 ` [PATCH 09/13] x86/efi: Firmware agnostic handover entry points Matt Fleming
2014-02-27 19:50 ` [PATCH 10/13] x86/efi: Add mixed runtime services support Matt Fleming
2014-02-27 19:50 ` [PATCH 11/13] x86/efi: Wire up CONFIG_EFI_MIXED Matt Fleming
2014-02-27 19:50 ` Matt Fleming [this message]
2014-02-27 19:51 ` [PATCH 13/13] x86/efi: Re-disable interrupts after calling firmware services Matt Fleming
-- strict thread matches above, loose matches on Subject: below --
2014-03-04 13:14 [PATCH v2 00/13] EFI mixed mode Matt Fleming
2014-03-04 13:14 ` [PATCH 12/13] x86/boot: Don't overwrite cr4 when enabling PAE Matt Fleming
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