dc1e35c6e9
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>
88 lines
1.7 KiB
C
88 lines
1.7 KiB
C
/*
|
|
* 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);
|
|
}
|