/*
* Enable and initialize the xsave feature.
* Called once per system bootup.
*/
void __init fpu__init_system_xstate(void)
{
unsigned int eax, ebx, ecx, edx;
static int on_boot_cpu __initdata = 1;
int err;
WARN_ON_FPU(!on_boot_cpu);
on_boot_cpu = 0;
if (!cpu_has_xsave) {
pr_info("x86/fpu: Legacy x87 FPU detected.\n");
return;
}
if (boot_cpu_data.cpuid_level < XSTATE_CPUID) {
WARN_ON_FPU(1);
return;
}
cpuid_count(XSTATE_CPUID, 0, &eax, &ebx, &ecx, &edx);
xfeatures_mask = eax + ((u64)edx << 32);
if ((xfeatures_mask & XFEATURE_MASK_FPSSE) != XFEATURE_MASK_FPSSE) {
pr_err("x86/fpu: FP/SSE not present amongst the CPU's xstate features: 0x%llx.\n", xfeatures_mask);
BUG();
}
xfeatures_mask &= fpu__get_supported_xfeatures_mask();
/* Enable xstate instructions to be able to continue with initialization: */
fpu__init_cpu_xstate();
err = init_xstate_size();
if (err) {
/* something went wrong, boot without any XSAVE support */
fpu__init_disable_system_xstate();
return;
}
update_regset_xstate_info(xstate_size, xfeatures_mask);
fpu__init_prepare_fx_sw_frame();
setup_init_fpu_buf();
setup_xstate_comp();
pr_info("x86/fpu: Enabled xstate features 0x%llx, context size is %d bytes, using '%s' format.\n",
xfeatures_mask,
xstate_size,
cpu_has_xsaves ? "compacted" : "standard");
}
/*
* setup the xstate image representing the init state
*/
static void __init setup_init_fpu_buf(void)
{
static int on_boot_cpu = 1;
WARN_ON_FPU(!on_boot_cpu);
on_boot_cpu = 0;
if (!cpu_has_xsave)
return;
setup_xstate_features();
print_xstate_features();
if (cpu_has_xsaves) {
init_fpstate.xsave.header.xcomp_bv = (u64)1 << 63 | xfeatures_mask;
init_fpstate.xsave.header.xfeatures = xfeatures_mask;
}
/*
* Init all the features state with header_bv being 0x0
*/
copy_kernel_to_xregs_booting(&init_fpstate.xsave);
/*
* Dump the init state again. This is to identify the init state
* of any feature which is not represented by all zero's.
*/
copy_xregs_to_kernel_booting(&init_fpstate.xsave);
}
/*
* Enable and initialize the xsave feature.
* Called once per system bootup.
*/
void __init fpu__init_system_xstate(void)
{
unsigned int eax, ebx, ecx, edx;
static int on_boot_cpu = 1;
WARN_ON_FPU(!on_boot_cpu);
on_boot_cpu = 0;
if (!cpu_has_xsave) {
pr_info("x86/fpu: Legacy x87 FPU detected.\n");
return;
}
if (boot_cpu_data.cpuid_level < XSTATE_CPUID) {
WARN_ON_FPU(1);
return;
}
cpuid_count(XSTATE_CPUID, 0, &eax, &ebx, &ecx, &edx);
xfeatures_mask = eax + ((u64)edx << 32);
if ((xfeatures_mask & XSTATE_FPSSE) != XSTATE_FPSSE) {
pr_err("x86/fpu: FP/SSE not present amongst the CPU's xstate features: 0x%llx.\n", xfeatures_mask);
BUG();
}
/* Support only the state known to the OS: */
xfeatures_mask = xfeatures_mask & XCNTXT_MASK;
/* Enable xstate instructions to be able to continue with initialization: */
fpu__init_cpu_xstate();
/* Recompute the context size for enabled features: */
init_xstate_size();
update_regset_xstate_info(xstate_size, xfeatures_mask);
fpu__init_prepare_fx_sw_frame();
setup_init_fpu_buf();
setup_xstate_comp();
pr_info("x86/fpu: Enabled xstate features 0x%llx, context size is 0x%x bytes, using '%s' format.\n",
xfeatures_mask,
xstate_size,
cpu_has_xsaves ? "compacted" : "standard");
}
