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Message-Id: <1448658575-17029-2-git-send-email-matt@codeblueprint.co.uk>
Date: Fri, 27 Nov 2015 21:09:30 +0000
From: Matt Fleming <matt@...eblueprint.co.uk>
To: Ingo Molnar <mingo@...nel.org>,
Thomas Gleixner <tglx@...utronix.de>,
"H . Peter Anvin" <hpa@...or.com>
Cc: Toshi Kani <toshi.kani@...com>,
Matt Fleming <matt@...eblueprint.co.uk>,
linux-kernel@...r.kernel.org, linux-efi@...r.kernel.org,
Sai Praneeth Prakhya <sai.praneeth.prakhya@...el.com>,
Dave Hansen <dave.hansen@...el.com>,
Borislav Petkov <bp@...en8.de>
Subject: [PATCH v4 1/6] x86: Page align _end to avoid pfn conversion bugs
Ingo noted that if we can guarantee _end is aligned to PAGE_SIZE we
can automatically avoid bugs along the lines of,
size = _end - _text >> PAGE_SHIFT
which is missing a call to PFN_ALIGN(). The EFI mixed mode contains
this bug, for example.
_text is already aligned to PAGE_SIZE through the use of
LOAD_PHYSICAL_ADDR, and the BSS and BRK sections are explicitly
aligned in the linker script, so it makes sense to align _end to
match.
Reported-by: Ingo Molnar <mingo@...nel.org>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: "H . Peter Anvin" <hpa@...or.com>
Cc: Toshi Kani <toshi.kani@...com>
Cc: Sai Praneeth Prakhya <sai.praneeth.prakhya@...el.com>
Cc: Dave Hansen <dave.hansen@...el.com>
Cc: Borislav Petkov <bp@...en8.de>
Signed-off-by: Matt Fleming <matt@...eblueprint.co.uk>
---
arch/x86/kernel/vmlinux.lds.S | 1 +
1 file changed, 1 insertion(+)
diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S
index 74e4bf11f562..4f1994257a18 100644
--- a/arch/x86/kernel/vmlinux.lds.S
+++ b/arch/x86/kernel/vmlinux.lds.S
@@ -325,6 +325,7 @@ SECTIONS
__brk_limit = .;
}
+ . = ALIGN(PAGE_SIZE);
_end = .;
STABS_DEBUG
--
2.6.2
--
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