diff options
author | Suresh Siddha <suresh.b.siddha@intel.com> | 2008-07-29 10:29:19 -0700 |
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committer | Ingo Molnar <mingo@elte.hu> | 2008-07-30 19:49:24 +0200 |
commit | dc1e35c6e95e8923cf1d3510438b63c600fee1e2 (patch) | |
tree | 4348f51f1bfdd124efd6d16dcc552bd4a148fdfb /arch/x86/kernel/xsave.c | |
parent | a648bf4632628c787abb0514277f2a231fca39ca (diff) | |
download | linux-dc1e35c6e95e8923cf1d3510438b63c600fee1e2.tar.bz2 |
x86, xsave: enable xsave/xrstor on cpus with xsave support
Enables xsave/xrstor by turning on cr4.osxsave on cpu's which have
the xsave support. For now, features that OS supports/enabled are
FP and SSE.
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/x86/kernel/xsave.c')
-rw-r--r-- | arch/x86/kernel/xsave.c | 87 |
1 files changed, 87 insertions, 0 deletions
diff --git a/arch/x86/kernel/xsave.c b/arch/x86/kernel/xsave.c new file mode 100644 index 000000000000..c68b7c4ca249 --- /dev/null +++ b/arch/x86/kernel/xsave.c @@ -0,0 +1,87 @@ +/* + * xsave/xrstor support. + * + * Author: Suresh Siddha <suresh.b.siddha@intel.com> + */ +#include <linux/bootmem.h> +#include <linux/compat.h> +#include <asm/i387.h> + +/* + * Supported feature mask by the CPU and the kernel. + */ +unsigned int pcntxt_hmask, pcntxt_lmask; + +/* + * Represents init state for the supported extended state. + */ +struct xsave_struct *init_xstate_buf; + +/* + * Enable the extended processor state save/restore feature + */ +void __cpuinit xsave_init(void) +{ + if (!cpu_has_xsave) + return; + + set_in_cr4(X86_CR4_OSXSAVE); + + /* + * Enable all the features that the HW is capable of + * and the Linux kernel is aware of. + * + * xsetbv(); + */ + asm volatile(".byte 0x0f,0x01,0xd1" : : "c" (0), + "a" (pcntxt_lmask), "d" (pcntxt_hmask)); +} + +/* + * setup the xstate image representing the init state + */ +void setup_xstate_init(void) +{ + init_xstate_buf = alloc_bootmem(xstate_size); + init_xstate_buf->i387.mxcsr = MXCSR_DEFAULT; +} + +/* + * Enable and initialize the xsave feature. + */ +void __init xsave_cntxt_init(void) +{ + unsigned int eax, ebx, ecx, edx; + + cpuid_count(0xd, 0, &eax, &ebx, &ecx, &edx); + + pcntxt_lmask = eax; + pcntxt_hmask = edx; + + if ((pcntxt_lmask & XSTATE_FPSSE) != XSTATE_FPSSE) { + printk(KERN_ERR "FP/SSE not shown under xsave features %x\n", + pcntxt_lmask); + BUG(); + } + + /* + * for now OS knows only about FP/SSE + */ + pcntxt_lmask = pcntxt_lmask & XCNTXT_LMASK; + pcntxt_hmask = pcntxt_hmask & XCNTXT_HMASK; + + xsave_init(); + + /* + * Recompute the context size for enabled features + */ + cpuid_count(0xd, 0, &eax, &ebx, &ecx, &edx); + + xstate_size = ebx; + + setup_xstate_init(); + + printk(KERN_INFO "xsave/xrstor: enabled xstate_bv 0x%Lx, " + "cntxt size 0x%x\n", + (pcntxt_lmask | ((u64) pcntxt_hmask << 32)), xstate_size); +} |