linux-kernel - [tip:x86/mm2] x86, boot: Move checking of cmd_line

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Message-ID: <tip-16a4baa642cf448742aaf150c4daa093f9dbebbb@git.kernel.org>
Date:	Tue, 29 Jan 2013 17:36:21 -0800
From:	tip-bot for Yinghai Lu <yinghai@...nel.org>
To:	linux-tip-commits@...r.kernel.org
Cc:	linux-kernel@...r.kernel.org, hpa@...or.com, mingo@...nel.org,
	yinghai@...nel.org, tglx@...utronix.de, hpa@...ux.intel.com
Subject: [tip:x86/mm2] x86, boot:
  Move checking of cmd_line_ptr out of common path

Commit-ID:  16a4baa642cf448742aaf150c4daa093f9dbebbb
Gitweb:     http://git.kernel.org/tip/16a4baa642cf448742aaf150c4daa093f9dbebbb
Author:     Yinghai Lu <yinghai@...nel.org>
AuthorDate: Thu, 24 Jan 2013 12:19:58 -0800
Committer:  H. Peter Anvin <hpa@...ux.intel.com>
CommitDate: Tue, 29 Jan 2013 15:26:01 -0800

x86, boot: Move checking of cmd_line_ptr out of common path

cmdline.c::__cmdline_find_option... are shared between 16-bit setup code
and 32/64 bit decompressor code.

for 32/64 only path via kexec, we should not check if ptr is less 1M.
as those cmdline could be put above 1M, or even 4G.

Move out accessible checking out of __cmdline_find_option()
So decompressor in misc.c can parse cmdline correctly.

Signed-off-by: Yinghai Lu <yinghai@...nel.org>
Link: http://lkml.kernel.org/r/1359058816-7615-18-git-send-email-yinghai@kernel.org
Signed-off-by: H. Peter Anvin <hpa@...ux.intel.com>
---
 arch/x86/boot/boot.h    | 14 ++++++++++++--
 arch/x86/boot/cmdline.c |  8 ++++----
 2 files changed, 16 insertions(+), 6 deletions(-)

diff --git a/arch/x86/boot/boot.h b/arch/x86/boot/boot.h
index 18997e5..7fadf80 100644
--- a/arch/x86/boot/boot.h
+++ b/arch/x86/boot/boot.h
@@ -289,12 +289,22 @@ int __cmdline_find_option(u32 cmdline_ptr, const char *option, char *buffer, int
 int __cmdline_find_option_bool(u32 cmdline_ptr, const char *option);
 static inline int cmdline_find_option(const char *option, char *buffer, int bufsize)
 {
-	return __cmdline_find_option(boot_params.hdr.cmd_line_ptr, option, buffer, bufsize);
+	u32 cmd_line_ptr = boot_params.hdr.cmd_line_ptr;
+
+	if (cmd_line_ptr >= 0x100000)
+		return -1;      /* inaccessible */
+
+	return __cmdline_find_option(cmd_line_ptr, option, buffer, bufsize);
 }
 
 static inline int cmdline_find_option_bool(const char *option)
 {
-	return __cmdline_find_option_bool(boot_params.hdr.cmd_line_ptr, option);
+	u32 cmd_line_ptr = boot_params.hdr.cmd_line_ptr;
+
+	if (cmd_line_ptr >= 0x100000)
+		return -1;      /* inaccessible */
+
+	return __cmdline_find_option_bool(cmd_line_ptr, option);
 }
 
 
diff --git a/arch/x86/boot/cmdline.c b/arch/x86/boot/cmdline.c
index 6b3b6f7..768f00f 100644
--- a/arch/x86/boot/cmdline.c
+++ b/arch/x86/boot/cmdline.c
@@ -41,8 +41,8 @@ int __cmdline_find_option(u32 cmdline_ptr, const char *option, char *buffer, int
 		st_bufcpy	/* Copying this to buffer */
 	} state = st_wordstart;
 
-	if (!cmdline_ptr || cmdline_ptr >= 0x100000)
-		return -1;	/* No command line, or inaccessible */
+	if (!cmdline_ptr)
+		return -1;      /* No command line */
 
 	cptr = cmdline_ptr & 0xf;
 	set_fs(cmdline_ptr >> 4);
@@ -111,8 +111,8 @@ int __cmdline_find_option_bool(u32 cmdline_ptr, const char *option)
 		st_wordskip,	/* Miscompare, skip */
 	} state = st_wordstart;
 
-	if (!cmdline_ptr || cmdline_ptr >= 0x100000)
-		return -1;	/* No command line, or inaccessible */
+	if (!cmdline_ptr)
+		return -1;      /* No command line */
 
 	cptr = cmdline_ptr & 0xf;
 	set_fs(cmdline_ptr >> 4);
--
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