linux-kernel - [PATCH 07/23] x86, realmode: Set permission for real mode pages

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Date:	Tue,  8 May 2012 21:22:30 +0300
From:	Jarkko Sakkinen <jarkko.sakkinen@...el.com>
To:	linux-kernel@...r.kernel.org
Cc:	linux-kbuild@...r.kernel.org, Michal Marek <mmarek@...e.cz>,
	Sam Ravnborg <sam@...nborg.org>,
	Joseph Cihula <joseph.cihula@...el.com>,
	Shane Wang <shane.wang@...el.com>, hpa@...ux.intel.com,
	Jarkko Sakkinen <jarkko.sakkinen@...el.com>
Subject: [PATCH 07/23] 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>
---
 arch/x86/kernel/realmode.c |   16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

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;
 }
 
-- 
1.7.9.5

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