From: Dave Hansen <[email protected]>
3.4.106-rc1 review patch. If anyone has any objections, please let me know.
------------------
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 <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: Fenghua Yu <[email protected]>
Cc: [email protected]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Thomas Gleixner <[email protected]>
Signed-off-by: Zefan Li <[email protected]>
---
arch/x86/kernel/cpu/common.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index cf79302..114db0f 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -142,6 +142,8 @@ 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);
return 1;
--
1.9.1
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