linux-kernel - [tip:x86/trampoline] x86, realmode: Set permission for real mode pages

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Message-ID: <tip-f156ffc439951b63cfa9f4d999a8d54267f13282@git.kernel.org>
Date:	Tue, 8 May 2012 15:19:09 -0700
From:	tip-bot for Jarkko Sakkinen <jarkko.sakkinen@...el.com>
To:	linux-tip-commits@...r.kernel.org
Cc:	linux-kernel@...r.kernel.org, hpa@...or.com, mingo@...nel.org,
	jarkko.sakkinen@...el.com, tglx@...utronix.de, hpa@...ux.intel.com
Subject: [tip:x86/trampoline] x86, realmode:
  Set permission for real mode pages

Commit-ID:  f156ffc439951b63cfa9f4d999a8d54267f13282
Gitweb:     http://git.kernel.org/tip/f156ffc439951b63cfa9f4d999a8d54267f13282
Author:     Jarkko Sakkinen <jarkko.sakkinen@...el.com>
AuthorDate: Tue, 8 May 2012 21:22:30 +0300
Committer:  H. Peter Anvin <hpa@...ux.intel.com>
CommitDate: Tue, 8 May 2012 11:47:08 -0700

x86, realmode: Set permission for real mode pages

Set proper permissions for rodata, text and data, removing the
realmode trampoline area as a remaining RWX memory mapping in the
kernel.

Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@...el.com>
Link: http://lkml.kernel.org/r/1336501366-28617-8-git-send-email-jarkko.sakkinen@intel.com
Signed-off-by: H. Peter Anvin <hpa@...ux.intel.com>
---
 arch/x86/kernel/realmode.c |   16 +++++++++++++++-
 1 files changed, 15 insertions(+), 1 deletions(-)

diff --git a/arch/x86/kernel/realmode.c b/arch/x86/kernel/realmode.c
index a465775..d85ac20 100644
--- a/arch/x86/kernel/realmode.c
+++ b/arch/x86/kernel/realmode.c
@@ -86,7 +86,21 @@ static int __init set_real_mode_permissions(void)
 		PAGE_ALIGN(real_mode_header.end) -
 		__pa(real_mode_base);
 
-	set_memory_x((unsigned long) real_mode_base, all_size >> PAGE_SHIFT);
+	size_t ro_size =
+		PAGE_ALIGN(real_mode_header.ro_end) -
+		__pa(real_mode_base);
+
+	size_t text_size =
+		PAGE_ALIGN(real_mode_header.ro_end) -
+		real_mode_header.text_start;
+
+	unsigned long text_start =
+		(unsigned long) __va(real_mode_header.text_start);
+
+	set_memory_nx((unsigned long) real_mode_base, all_size >> PAGE_SHIFT);
+	set_memory_ro((unsigned long) real_mode_base, ro_size >> PAGE_SHIFT);
+	set_memory_x((unsigned long) text_start, text_size >> PAGE_SHIFT);
+
 	return 0;
 }
 
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