Merge tag 'x86_fpu_for_v6.0_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 fpu update from Borislav Petkov:

 - Add machinery to initialize AMX register state in order for
   AMX-capable CPUs to be able to enter deeper low-power state

* tag 'x86_fpu_for_v6.0_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  intel_idle: Add a new flag to initialize the AMX state
  x86/fpu: Add a helper to prepare AMX state for low-power CPU idle

1 files changed, 23 insertions, 2 deletions

diff --git a/drivers/idle/intel_idle.c b/drivers/idle/intel_idle.c
index 907700d1e78e..445b19d20b9a 100644
--- a/drivers/idle/intel_idle.c
+++ b/drivers/idle/intel_idle.c
@@ -56,6 +56,7 @@
 #include <asm/nospec-branch.h>
 #include <asm/mwait.h>
 #include <asm/msr.h>
+#include <asm/fpu/api.h>
 
 #define INTEL_IDLE_VERSION "0.5.1"
 
@@ -114,6 +115,11 @@ static unsigned int mwait_substates __initdata;
 #define CPUIDLE_FLAG_IBRS		BIT(16)
 
 /*
+ * Initialize large xstate for the C6-state entrance.
+ */
+#define CPUIDLE_FLAG_INIT_XSTATE	BIT(17)
+
+/*
  * MWAIT takes an 8-bit "hint" in EAX "suggesting"
  * the C-state (top nibble) and sub-state (bottom nibble)
  * 0x00 means "MWAIT(C1)", 0x10 means "MWAIT(C2)" etc.
@@ -191,6 +197,13 @@ static __cpuidle int intel_idle_ibrs(struct cpuidle_device *dev,
 	return ret;
 }
 
+static __cpuidle int intel_idle_xstate(struct cpuidle_device *dev,
+				       struct cpuidle_driver *drv, int index)
+{
+	fpu_idle_fpregs();
+	return __intel_idle(dev, drv, index);
+}
+
 /**
  * intel_idle_s2idle - Ask the processor to enter the given idle state.
  * @dev: cpuidle device of the target CPU.
@@ -206,8 +219,12 @@ static __cpuidle int intel_idle_ibrs(struct cpuidle_device *dev,
 static __cpuidle int intel_idle_s2idle(struct cpuidle_device *dev,
 				       struct cpuidle_driver *drv, int index)
 {
-	unsigned long eax = flg2MWAIT(drv->states[index].flags);
 	unsigned long ecx = 1; /* break on interrupt flag */
+	struct cpuidle_state *state = &drv->states[index];
+	unsigned long eax = flg2MWAIT(state->flags);
+
+	if (state->flags & CPUIDLE_FLAG_INIT_XSTATE)
+		fpu_idle_fpregs();
 
 	mwait_idle_with_hints(eax, ecx);
 
@@ -942,7 +959,8 @@ static struct cpuidle_state spr_cstates[] __initdata = {
 	{
 		.name = "C6",
 		.desc = "MWAIT 0x20",
-		.flags = MWAIT2flg(0x20) | CPUIDLE_FLAG_TLB_FLUSHED,
+		.flags = MWAIT2flg(0x20) | CPUIDLE_FLAG_TLB_FLUSHED |
+					   CPUIDLE_FLAG_INIT_XSTATE,
 		.exit_latency = 290,
 		.target_residency = 800,
 		.enter = &intel_idle,
@@ -1857,6 +1875,9 @@ static void __init intel_idle_init_cstates_icpu(struct cpuidle_driver *drv)
 			drv->states[drv->state_count].enter = intel_idle_ibrs;
 		}
 
+		if (cpuidle_state_table[cstate].flags & CPUIDLE_FLAG_INIT_XSTATE)
+			drv->states[drv->state_count].enter = intel_idle_xstate;
+
 		if ((disabled_states_mask & BIT(drv->state_count)) ||
 		    ((icpu->use_acpi || force_use_acpi) &&
 		     intel_idle_off_by_default(mwait_hint) &&