[PATCH 3.17 015/122] x86: Require exact match for noxsave command line option
3.17-stable review patch. If anyone has any objections, please let me know.
--
From: Dave Hansen
commit 2cd3949f702692cf4c5d05b463f19cd706a92dd3 upstream.
We have some very similarly named command-line options:
arch/x86/kernel/cpu/common.c:__setup("noxsave", x86_xsave_setup);
arch/x86/kernel/cpu/common.c:__setup("noxsaveopt", x86_xsaveopt_setup);
arch/x86/kernel/cpu/common.c:__setup("noxsaves", x86_xsaves_setup);
__setup() is designed to match options that take arguments, like
"foo=bar" where you would have:
__setup("foo", x86_foo_func...);
The problem is that "noxsave" actually _matches_ "noxsaves" in
the same way that "foo" matches "foo=bar". If you boot an old
kernel that does not know about "noxsaves" with "noxsaves" on the
command line, it will interpret the argument as "noxsave", which
is not what you want at all.
This makes the "noxsave" handler only return success when it finds
an *exact* match.
[ tglx: We really need to make __setup() more robust. ]
Signed-off-by: Dave Hansen
Cc: Dave Hansen
Cc: Fenghua Yu
Cc: x...@kernel.org
Link: http://lkml.kernel.org/r/2014220133.fe053...@viggo.jf.intel.com
Signed-off-by: Thomas Gleixner
Signed-off-by: Greg Kroah-Hartman
---
arch/x86/kernel/cpu/common.c |2 ++
1 file changed, 2 insertions(+)
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -146,6 +146,8 @@ EXPORT_PER_CPU_SYMBOL_GPL(gdt_page);
static int __init x86_xsave_setup(char *s)
{
+ if (strlen(s))
+ return 0;
setup_clear_cpu_cap(X86_FEATURE_XSAVE);
setup_clear_cpu_cap(X86_FEATURE_XSAVEOPT);
setup_clear_cpu_cap(X86_FEATURE_XSAVES);
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[PATCH 3.17 015/122] x86: Require exact match for noxsave command line option
3.17-stable review patch. If anyone has any objections, please let me know.
--
From: Dave Hansen dave.han...@linux.intel.com
commit 2cd3949f702692cf4c5d05b463f19cd706a92dd3 upstream.
We have some very similarly named command-line options:
arch/x86/kernel/cpu/common.c:__setup(noxsave, x86_xsave_setup);
arch/x86/kernel/cpu/common.c:__setup(noxsaveopt, x86_xsaveopt_setup);
arch/x86/kernel/cpu/common.c:__setup(noxsaves, x86_xsaves_setup);
__setup() is designed to match options that take arguments, like
foo=bar where you would have:
__setup(foo, x86_foo_func...);
The problem is that noxsave actually _matches_ noxsaves in
the same way that foo matches foo=bar. If you boot an old
kernel that does not know about noxsaves with noxsaves on the
command line, it will interpret the argument as noxsave, which
is not what you want at all.
This makes the noxsave handler only return success when it finds
an *exact* match.
[ tglx: We really need to make __setup() more robust. ]
Signed-off-by: Dave Hansen dave.han...@linux.intel.com
Cc: Dave Hansen d...@sr71.net
Cc: Fenghua Yu fenghua...@intel.com
Cc: x...@kernel.org
Link: http://lkml.kernel.org/r/2014220133.fe053...@viggo.jf.intel.com
Signed-off-by: Thomas Gleixner t...@linutronix.de
Signed-off-by: Greg Kroah-Hartman gre...@linuxfoundation.org
---
arch/x86/kernel/cpu/common.c |2 ++
1 file changed, 2 insertions(+)
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -146,6 +146,8 @@ EXPORT_PER_CPU_SYMBOL_GPL(gdt_page);
static int __init x86_xsave_setup(char *s)
{
+ if (strlen(s))
+ return 0;
setup_clear_cpu_cap(X86_FEATURE_XSAVE);
setup_clear_cpu_cap(X86_FEATURE_XSAVEOPT);
setup_clear_cpu_cap(X86_FEATURE_XSAVES);
--
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