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| author | Suresh Siddha <suresh.b.siddha@intel.com> | 2009-05-22 12:17:45 -0700 |
|---|---|---|
| committer | H. Peter Anvin <hpa@zytor.com> | 2009-05-22 13:10:54 -0700 |
| commit | 0c752a93353d9b17dbe148312d732fbe06d235e1 (patch) | |
| tree | 944b37d214dd478abc1c5d2b51573ec87be59c63 | |
| parent | bca23dba760d6705c013f89113c46570378fb626 (diff) | |
| download | linux-0c752a93353d9b17dbe148312d732fbe06d235e1.tar.bz2 | |
x86: introduce noxsave boot parameter
Introduce "noxsave" boot parameter which will disable the cpu's xsave/xrstor
capabilities. Useful for debugging and working around xsave related issues.
[ Impact: make it possible to debug problems in the field ]
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
| -rw-r--r-- | Documentation/kernel-parameters.txt | 4 | ||||
| -rw-r--r-- | arch/x86/kernel/cpu/common.c | 7 |
2 files changed, 11 insertions, 0 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index e87bdbfbcc75..fd5cac013037 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -1535,6 +1535,10 @@ and is between 256 and 4096 characters. It is defined in the file register save and restore. The kernel will only save legacy floating-point registers on task switch. + noxsave [BUGS=X86] Disables x86 extended register state save + and restore using xsave. The kernel will fallback to + enabling legacy floating-point and sse state. + nohlt [BUGS=ARM,SH] Tells the kernel that the sleep(SH) or wfi(ARM) instruction doesn't work correctly and not to use it. This is also useful when using JTAG debugger. diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index c1caefc82e62..77848d9fca68 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -114,6 +114,13 @@ DEFINE_PER_CPU_PAGE_ALIGNED(struct gdt_page, gdt_page) = { .gdt = { } }; EXPORT_PER_CPU_SYMBOL_GPL(gdt_page); +static int __init x86_xsave_setup(char *s) +{ + setup_clear_cpu_cap(X86_FEATURE_XSAVE); + return 1; +} +__setup("noxsave", x86_xsave_setup); + #ifdef CONFIG_X86_32 static int cachesize_override __cpuinitdata = -1; static int disable_x86_serial_nr __cpuinitdata = 1; |