x86/fpu: Move xstate size to fpu_*_cfg

Use the new kernel and user space config storage to store and retrieve the
XSTATE buffer sizes. The default and the maximum size are the same for now,
but will change when support for dynamically enabled features is added.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20211014230739.296830097@linutronix.de

1 files changed, 14 insertions, 17 deletions

diff --git a/arch/x86/kernel/fpu/init.c b/arch/x86/kernel/fpu/init.c
index c9293ade321d..58043ed08662 100644
--- a/arch/x86/kernel/fpu/init.c
+++ b/arch/x86/kernel/fpu/init.c
@@ -133,14 +133,6 @@ static void __init fpu__init_system_generic(void)
 	fpu__init_system_mxcsr();
 }
 
-/*
- * Size of the FPU context state. All tasks in the system use the
- * same context size, regardless of what portion they use.
- * This is inherent to the XSAVE architecture which puts all state
- * components into a single, continuous memory block:
- */
-unsigned int fpu_kernel_xstate_size __ro_after_init;
-
 /* Get alignment of the TYPE. */
 #define TYPE_ALIGN(TYPE) offsetof(struct { char x; TYPE test; }, test)
 
@@ -171,7 +163,7 @@ static void __init fpu__init_task_struct_size(void)
 	 * Add back the dynamically-calculated register state
 	 * size.
 	 */
-	task_size += fpu_kernel_xstate_size;
+	task_size += fpu_kernel_cfg.default_size;
 
 	/*
 	 * We dynamically size 'struct fpu', so we require that
@@ -195,25 +187,30 @@ static void __init fpu__init_task_struct_size(void)
  */
 static void __init fpu__init_system_xstate_size_legacy(void)
 {
+	unsigned int size;
+
 	/*
-	 * Note that xstate sizes might be overwritten later during
-	 * fpu__init_system_xstate().
+	 * Note that the size configuration might be overwritten later
+	 * during fpu__init_system_xstate().
 	 */
 	if (!cpu_feature_enabled(X86_FEATURE_FPU))
-		fpu_kernel_xstate_size = sizeof(struct swregs_state);
+		size = sizeof(struct swregs_state);
 	else if (cpu_feature_enabled(X86_FEATURE_FXSR))
-		fpu_kernel_xstate_size = sizeof(struct fxregs_state);
+		size = sizeof(struct fxregs_state);
 	else
-		fpu_kernel_xstate_size = sizeof(struct fregs_state);
+		size = sizeof(struct fregs_state);
 
-	fpu_user_xstate_size = fpu_kernel_xstate_size;
+	fpu_kernel_cfg.max_size = size;
+	fpu_kernel_cfg.default_size = size;
+	fpu_user_cfg.max_size = size;
+	fpu_user_cfg.default_size = size;
 	fpstate_reset(&current->thread.fpu);
 }
 
 static void __init fpu__init_init_fpstate(void)
 {
 	/* Bring init_fpstate size and features up to date */
-	init_fpstate.size		= fpu_kernel_xstate_size;
+	init_fpstate.size		= fpu_kernel_cfg.max_size;
 	init_fpstate.xfeatures		= xfeatures_mask_all;
 }
 
@@ -234,7 +231,7 @@ void __init fpu__init_system(struct cpuinfo_x86 *c)
 
 	fpu__init_system_generic();
 	fpu__init_system_xstate_size_legacy();
-	fpu__init_system_xstate();
+	fpu__init_system_xstate(fpu_kernel_cfg.max_size);
 	fpu__init_task_struct_size();
 	fpu__init_init_fpstate();
 }