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>
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@ -1535,6 +1535,10 @@ and is between 256 and 4096 characters. It is defined in the file
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register save and restore. The kernel will only save
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register save and restore. The kernel will only save
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legacy floating-point registers on task switch.
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legacy floating-point registers on task switch.
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noxsave [BUGS=X86] Disables x86 extended register state save
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and restore using xsave. The kernel will fallback to
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enabling legacy floating-point and sse state.
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nohlt [BUGS=ARM,SH] Tells the kernel that the sleep(SH) or
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nohlt [BUGS=ARM,SH] Tells the kernel that the sleep(SH) or
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wfi(ARM) instruction doesn't work correctly and not to
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wfi(ARM) instruction doesn't work correctly and not to
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use it. This is also useful when using JTAG debugger.
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use it. This is also useful when using JTAG debugger.
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@ -114,6 +114,13 @@ DEFINE_PER_CPU_PAGE_ALIGNED(struct gdt_page, gdt_page) = { .gdt = {
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} };
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} };
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EXPORT_PER_CPU_SYMBOL_GPL(gdt_page);
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EXPORT_PER_CPU_SYMBOL_GPL(gdt_page);
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static int __init x86_xsave_setup(char *s)
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{
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setup_clear_cpu_cap(X86_FEATURE_XSAVE);
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return 1;
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}
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__setup("noxsave", x86_xsave_setup);
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#ifdef CONFIG_X86_32
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#ifdef CONFIG_X86_32
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static int cachesize_override __cpuinitdata = -1;
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static int cachesize_override __cpuinitdata = -1;
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static int disable_x86_serial_nr __cpuinitdata = 1;
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static int disable_x86_serial_nr __cpuinitdata = 1;
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