The following commit has been merged into the x86/fpu branch of tip:
Commit-ID: 23686ef25d4ae81bc12fe3994d1905191fcf71f8
Gitweb: https://git.kernel.org/tip/23686ef25d4ae81bc12fe3994d1905191fcf71f8
Author: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
AuthorDate: Thu, 21 Oct 2021 15:55:11 -07:00
Committer: Borislav Petkov <bp@xxxxxxx>
CommitterDate: Tue, 26 Oct 2021 10:18:09 +02:00
x86/fpu: Add basic helpers for dynamically enabled features
To allow building up the infrastructure required to support dynamically
enabled FPU features, add:
- XFEATURES_MASK_DYNAMIC
This constant will hold xfeatures which can be dynamically enabled.
- fpu_state_size_dynamic()
A static branch for 64-bit and a simple 'return false' for 32-bit.
This helper allows to add dynamic-feature-specific changes to common
code which is shared between 32-bit and 64-bit without #ifdeffery.
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Chang S. Bae <chang.seok.bae@xxxxxxxxx>
Signed-off-by: Borislav Petkov <bp@xxxxxxx>
Link: https://lkml.kernel.org/r/20211021225527.10184-8-chang.seok.bae@xxxxxxxxx
---
arch/x86/include/asm/fpu/xstate.h | 21 +++++++++++++++++++++
arch/x86/kernel/fpu/core.c | 4 ++++
2 files changed, 25 insertions(+)
diff --git a/arch/x86/include/asm/fpu/xstate.h b/arch/x86/include/asm/fpu/xstate.h
index 43ae89d..cf28546 100644
--- a/arch/x86/include/asm/fpu/xstate.h
+++ b/arch/x86/include/asm/fpu/xstate.h
@@ -43,6 +43,9 @@
#define XFEATURE_MASK_USER_RESTORE \
(XFEATURE_MASK_USER_SUPPORTED & ~XFEATURE_MASK_PKRU)
+/* Features which are dynamically enabled for a process on request */
+#define XFEATURE_MASK_USER_DYNAMIC 0ULL
+
/* All currently supported supervisor features */
#define XFEATURE_MASK_SUPERVISOR_SUPPORTED (XFEATURE_MASK_PASID)
@@ -96,4 +99,22 @@ int xfeature_size(int xfeature_nr);
void xsaves(struct xregs_state *xsave, u64 mask);
void xrstors(struct xregs_state *xsave, u64 mask);
+#ifdef CONFIG_X86_64
+DECLARE_STATIC_KEY_FALSE(__fpu_state_size_dynamic);
+#endif
+
+#ifdef CONFIG_X86_64
+DECLARE_STATIC_KEY_FALSE(__fpu_state_size_dynamic);
+
+static __always_inline __pure bool fpu_state_size_dynamic(void)
+{
+ return static_branch_unlikely(&__fpu_state_size_dynamic);
+}
+#else
+static __always_inline __pure bool fpu_state_size_dynamic(void)
+{
+ return false;
+}
+#endif
+
#endif
diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c
index b05f6a3..4018083 100644
--- a/arch/x86/kernel/fpu/core.c
+++ b/arch/x86/kernel/fpu/core.c
@@ -25,6 +25,10 @@
#define CREATE_TRACE_POINTS
#include <asm/trace/fpu.h>
+#ifdef CONFIG_X86_64
+DEFINE_STATIC_KEY_FALSE(__fpu_state_size_dynamic);
+#endif
+
/* The FPU state configuration data for kernel and user space */
struct fpu_state_config fpu_kernel_cfg __ro_after_init;
struct fpu_state_config fpu_user_cfg __ro_after_init;
|