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-rw-r--r--arch/arm64/kernel/fpsimd.c52
1 files changed, 52 insertions, 0 deletions
diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c
index d7e5f8a2d4f5..bcde88e2d981 100644
--- a/arch/arm64/kernel/fpsimd.c
+++ b/arch/arm64/kernel/fpsimd.c
@@ -21,12 +21,15 @@
#include <linux/cpu_pm.h>
#include <linux/kernel.h>
#include <linux/init.h>
+#include <linux/preempt.h>
#include <linux/sched/signal.h>
#include <linux/signal.h>
#include <linux/hardirq.h>
#include <asm/fpsimd.h>
#include <asm/cputype.h>
+#include <asm/neon.h>
+#include <asm/simd.h>
#define FPEXC_IOF (1 << 0)
#define FPEXC_DZF (1 << 1)
@@ -276,6 +279,55 @@ void kernel_neon_end(void)
}
EXPORT_SYMBOL(kernel_neon_end);
+DEFINE_PER_CPU(struct fpsimd_state, efi_fpsimd_state);
+DEFINE_PER_CPU(bool, efi_fpsimd_state_used);
+
+/*
+ * EFI runtime services support functions
+ *
+ * The ABI for EFI runtime services allows EFI to use FPSIMD during the call.
+ * This means that for EFI (and only for EFI), we have to assume that FPSIMD
+ * is always used rather than being an optional accelerator.
+ *
+ * These functions provide the necessary support for ensuring FPSIMD
+ * save/restore in the contexts from which EFI is used.
+ *
+ * Do not use them for any other purpose -- if tempted to do so, you are
+ * either doing something wrong or you need to propose some refactoring.
+ */
+
+/*
+ * __efi_fpsimd_begin(): prepare FPSIMD for making an EFI runtime services call
+ */
+void __efi_fpsimd_begin(void)
+{
+ if (!system_supports_fpsimd())
+ return;
+
+ WARN_ON(preemptible());
+
+ if (may_use_simd())
+ kernel_neon_begin();
+ else {
+ fpsimd_save_state(this_cpu_ptr(&efi_fpsimd_state));
+ __this_cpu_write(efi_fpsimd_state_used, true);
+ }
+}
+
+/*
+ * __efi_fpsimd_end(): clean up FPSIMD after an EFI runtime services call
+ */
+void __efi_fpsimd_end(void)
+{
+ if (!system_supports_fpsimd())
+ return;
+
+ if (__this_cpu_xchg(efi_fpsimd_state_used, false))
+ fpsimd_load_state(this_cpu_ptr(&efi_fpsimd_state));
+ else
+ kernel_neon_end();
+}
+
#endif /* CONFIG_KERNEL_MODE_NEON */
#ifdef CONFIG_CPU_PM