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-rw-r--r--arch/arm64/kernel/fpsimd.c67
1 files changed, 61 insertions, 6 deletions
diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c
index 741fbbfa1265..1e531156f1d7 100644
--- a/arch/arm64/kernel/fpsimd.c
+++ b/arch/arm64/kernel/fpsimd.c
@@ -123,11 +123,13 @@ static int sve_default_vl = -1;
int __ro_after_init sve_max_vl = -1;
/* Set of available vector lengths, as vq_to_bit(vq): */
static __ro_after_init DECLARE_BITMAP(sve_vq_map, SVE_VQ_MAX);
+static void __percpu *efi_sve_state;
#else /* ! CONFIG_ARM64_SVE */
/* Dummy declaration for code that will be optimised out: */
extern __ro_after_init DECLARE_BITMAP(sve_vq_map, SVE_VQ_MAX);
+extern void __percpu *efi_sve_state;
#endif /* ! CONFIG_ARM64_SVE */
@@ -552,6 +554,30 @@ int sve_verify_vq_map(void)
return ret;
}
+static void __init sve_efi_setup(void)
+{
+ if (!IS_ENABLED(CONFIG_EFI))
+ return;
+
+ /*
+ * alloc_percpu() warns and prints a backtrace if this goes wrong.
+ * This is evidence of a crippled system and we are returning void,
+ * so no attempt is made to handle this situation here.
+ */
+ if (!sve_vl_valid(sve_max_vl))
+ goto fail;
+
+ efi_sve_state = __alloc_percpu(
+ SVE_SIG_REGS_SIZE(sve_vq_from_vl(sve_max_vl)), SVE_VQ_BYTES);
+ if (!efi_sve_state)
+ goto fail;
+
+ return;
+
+fail:
+ panic("Cannot allocate percpu memory for EFI SVE save/restore");
+}
+
/*
* Enable SVE for EL1.
* Intended for use by the cpufeatures code during CPU boot.
@@ -599,6 +625,8 @@ void __init sve_setup(void)
sve_max_vl);
pr_info("SVE: default vector length %u bytes per vector\n",
sve_default_vl);
+
+ sve_efi_setup();
}
/*
@@ -927,6 +955,7 @@ EXPORT_SYMBOL(kernel_neon_end);
static DEFINE_PER_CPU(struct fpsimd_state, efi_fpsimd_state);
static DEFINE_PER_CPU(bool, efi_fpsimd_state_used);
+static DEFINE_PER_CPU(bool, efi_sve_state_used);
/*
* EFI runtime services support functions
@@ -952,10 +981,24 @@ void __efi_fpsimd_begin(void)
WARN_ON(preemptible());
- if (may_use_simd())
+ if (may_use_simd()) {
kernel_neon_begin();
- else {
- fpsimd_save_state(this_cpu_ptr(&efi_fpsimd_state));
+ } else {
+ /*
+ * If !efi_sve_state, SVE can't be in use yet and doesn't need
+ * preserving:
+ */
+ if (system_supports_sve() && likely(efi_sve_state)) {
+ char *sve_state = this_cpu_ptr(efi_sve_state);
+
+ __this_cpu_write(efi_sve_state_used, true);
+
+ sve_save_state(sve_state + sve_ffr_offset(sve_max_vl),
+ &this_cpu_ptr(&efi_fpsimd_state)->fpsr);
+ } else {
+ fpsimd_save_state(this_cpu_ptr(&efi_fpsimd_state));
+ }
+
__this_cpu_write(efi_fpsimd_state_used, true);
}
}
@@ -968,10 +1011,22 @@ 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
+ if (!__this_cpu_xchg(efi_fpsimd_state_used, false)) {
kernel_neon_end();
+ } else {
+ if (system_supports_sve() &&
+ likely(__this_cpu_read(efi_sve_state_used))) {
+ char const *sve_state = this_cpu_ptr(efi_sve_state);
+
+ sve_load_state(sve_state + sve_ffr_offset(sve_max_vl),
+ &this_cpu_ptr(&efi_fpsimd_state)->fpsr,
+ sve_vq_from_vl(sve_get_vl()) - 1);
+
+ __this_cpu_write(efi_sve_state_used, false);
+ } else {
+ fpsimd_load_state(this_cpu_ptr(&efi_fpsimd_state));
+ }
+ }
}
#endif /* CONFIG_EFI */