arm64/sve: Put system wide vector length information into structs

With the introduction of SME we will have a second vector length in the
system, enumerated and configured in a very similar fashion to the
existing SVE vector length.  While there are a few differences in how
things are handled this is a relatively small portion of the overall
code so in order to avoid code duplication we factor out

We create two structs, one vl_info for the static hardware properties
and one vl_config for the runtime configuration, with an array
instantiated for each and update all the users to reference these. Some
accessor functions are provided where helpful for readability, and the
write to set the vector length is put into a function since the system
register being updated needs to be chosen at compile time.

This is a mostly mechanical replacement, further work will be required
to actually make things generic, ensuring that we handle those places
where there are differences properly.

Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20211019172247.3045838-8-broonie@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>

1 files changed, 92 insertions, 71 deletions

diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c
index f7eb54e9a8b8..9248c9efe5fd 100644
--- a/arch/arm64/kernel/fpsimd.c
+++ b/arch/arm64/kernel/fpsimd.c
@@ -121,40 +121,51 @@ struct fpsimd_last_state_struct {
 
 static DEFINE_PER_CPU(struct fpsimd_last_state_struct, fpsimd_last_state);
 
-/* Default VL for tasks that don't set it explicitly: */
-static int __sve_default_vl = -1;
+__ro_after_init struct vl_info vl_info[ARM64_VEC_MAX] = {
+#ifdef CONFIG_ARM64_SVE
+	[ARM64_VEC_SVE] = {
+		.type			= ARM64_VEC_SVE,
+		.name			= "SVE",
+		.min_vl			= SVE_VL_MIN,
+		.max_vl			= SVE_VL_MIN,
+		.max_virtualisable_vl	= SVE_VL_MIN,
+	},
+#endif
+};
+
+struct vl_config {
+	int __default_vl;		/* Default VL for tasks */
+};
+
+static struct vl_config vl_config[ARM64_VEC_MAX];
+
+static int get_default_vl(enum vec_type type)
+{
+	return READ_ONCE(vl_config[type].__default_vl);
+}
 
 static int get_sve_default_vl(void)
 {
-	return READ_ONCE(__sve_default_vl);
+	return get_default_vl(ARM64_VEC_SVE);
 }
 
 #ifdef CONFIG_ARM64_SVE
 
-static void set_sve_default_vl(int val)
+static void set_default_vl(enum vec_type type, int val)
 {
-	WRITE_ONCE(__sve_default_vl, val);
+	WRITE_ONCE(vl_config[type].__default_vl, val);
 }
 
-/* Maximum supported vector length across all CPUs (initially poisoned) */
-int __ro_after_init sve_max_vl = SVE_VL_MIN;
-int __ro_after_init sve_max_virtualisable_vl = SVE_VL_MIN;
-
-/*
- * Set of available vector lengths,
- * where length vq encoded as bit __vq_to_bit(vq):
- */
-__ro_after_init DECLARE_BITMAP(sve_vq_map, SVE_VQ_MAX);
-/* Set of vector lengths present on at least one cpu: */
-static __ro_after_init DECLARE_BITMAP(sve_vq_partial_map, SVE_VQ_MAX);
+static void set_sve_default_vl(int val)
+{
+	set_default_vl(ARM64_VEC_SVE, val);
+}
 
 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 __ro_after_init DECLARE_BITMAP(sve_vq_partial_map, SVE_VQ_MAX);
 extern void __percpu *efi_sve_state;
 
 #endif /* ! CONFIG_ARM64_SVE */
@@ -357,21 +368,23 @@ static void fpsimd_save(void)
  * If things go wrong there's a bug somewhere, but try to fall back to a
  * safe choice.
  */
-static unsigned int find_supported_sve_vector_length(unsigned int vl)
+static unsigned int find_supported_vector_length(enum vec_type type,
+						 unsigned int vl)
 {
+	struct vl_info *info = &vl_info[type];
 	int bit;
-	int max_vl = sve_max_vl;
+	int max_vl = info->max_vl;
 
 	if (WARN_ON(!sve_vl_valid(vl)))
-		vl = SVE_VL_MIN;
+		vl = info->min_vl;
 
 	if (WARN_ON(!sve_vl_valid(max_vl)))
-		max_vl = SVE_VL_MIN;
+		max_vl = info->min_vl;
 
 	if (vl > max_vl)
 		vl = max_vl;
 
-	bit = find_next_bit(sve_vq_map, SVE_VQ_MAX,
+	bit = find_next_bit(info->vq_map, SVE_VQ_MAX,
 			    __vq_to_bit(sve_vq_from_vl(vl)));
 	return sve_vl_from_vq(__bit_to_vq(bit));
 }
@@ -381,6 +394,7 @@ static unsigned int find_supported_sve_vector_length(unsigned int vl)
 static int sve_proc_do_default_vl(struct ctl_table *table, int write,
 				  void *buffer, size_t *lenp, loff_t *ppos)
 {
+	struct vl_info *info = &vl_info[ARM64_VEC_SVE];
 	int ret;
 	int vl = get_sve_default_vl();
 	struct ctl_table tmp_table = {
@@ -394,12 +408,12 @@ static int sve_proc_do_default_vl(struct ctl_table *table, int write,
 
 	/* Writing -1 has the special meaning "set to max": */
 	if (vl == -1)
-		vl = sve_max_vl;
+		vl = info->max_vl;
 
 	if (!sve_vl_valid(vl))
 		return -EINVAL;
 
-	set_sve_default_vl(find_supported_sve_vector_length(vl));
+	set_sve_default_vl(find_supported_vector_length(ARM64_VEC_SVE, vl));
 	return 0;
 }
 
@@ -618,7 +632,7 @@ int sve_set_vector_length(struct task_struct *task,
 	if (vl > SVE_VL_ARCH_MAX)
 		vl = SVE_VL_ARCH_MAX;
 
-	vl = find_supported_sve_vector_length(vl);
+	vl = find_supported_vector_length(ARM64_VEC_SVE, vl);
 
 	if (flags & (PR_SVE_VL_INHERIT |
 		     PR_SVE_SET_VL_ONEXEC))
@@ -716,18 +730,15 @@ int sve_get_current_vl(void)
 	return sve_prctl_status(0);
 }
 
-static void sve_probe_vqs(DECLARE_BITMAP(map, SVE_VQ_MAX))
+static void vec_probe_vqs(struct vl_info *info,
+			  DECLARE_BITMAP(map, SVE_VQ_MAX))
 {
 	unsigned int vq, vl;
-	unsigned long zcr;
 
 	bitmap_zero(map, SVE_VQ_MAX);
 
-	zcr = ZCR_ELx_LEN_MASK;
-	zcr = read_sysreg_s(SYS_ZCR_EL1) & ~zcr;
-
 	for (vq = SVE_VQ_MAX; vq >= SVE_VQ_MIN; --vq) {
-		write_sysreg_s(zcr | (vq - 1), SYS_ZCR_EL1); /* self-syncing */
+		write_vl(info->type, vq - 1); /* self-syncing */
 		vl = sve_get_vl();
 		vq = sve_vq_from_vl(vl); /* skip intervening lengths */
 		set_bit(__vq_to_bit(vq), map);
@@ -738,10 +749,11 @@ static void sve_probe_vqs(DECLARE_BITMAP(map, SVE_VQ_MAX))
  * Initialise the set of known supported VQs for the boot CPU.
  * This is called during kernel boot, before secondary CPUs are brought up.
  */
-void __init sve_init_vq_map(void)
+void __init vec_init_vq_map(enum vec_type type)
 {
-	sve_probe_vqs(sve_vq_map);
-	bitmap_copy(sve_vq_partial_map, sve_vq_map, SVE_VQ_MAX);
+	struct vl_info *info = &vl_info[type];
+	vec_probe_vqs(info, info->vq_map);
+	bitmap_copy(info->vq_partial_map, info->vq_map, SVE_VQ_MAX);
 }
 
 /*
@@ -749,30 +761,33 @@ void __init sve_init_vq_map(void)
  * those not supported by the current CPU.
  * This function is called during the bring-up of early secondary CPUs only.
  */
-void sve_update_vq_map(void)
+void vec_update_vq_map(enum vec_type type)
 {
+	struct vl_info *info = &vl_info[type];
 	DECLARE_BITMAP(tmp_map, SVE_VQ_MAX);
 
-	sve_probe_vqs(tmp_map);
-	bitmap_and(sve_vq_map, sve_vq_map, tmp_map, SVE_VQ_MAX);
-	bitmap_or(sve_vq_partial_map, sve_vq_partial_map, tmp_map, SVE_VQ_MAX);
+	vec_probe_vqs(info, tmp_map);
+	bitmap_and(info->vq_map, info->vq_map, tmp_map, SVE_VQ_MAX);
+	bitmap_or(info->vq_partial_map, info->vq_partial_map, tmp_map,
+		  SVE_VQ_MAX);
 }
 
 /*
  * Check whether the current CPU supports all VQs in the committed set.
  * This function is called during the bring-up of late secondary CPUs only.
  */
-int sve_verify_vq_map(void)
+int vec_verify_vq_map(enum vec_type type)
 {
+	struct vl_info *info = &vl_info[type];
 	DECLARE_BITMAP(tmp_map, SVE_VQ_MAX);
 	unsigned long b;
 
-	sve_probe_vqs(tmp_map);
+	vec_probe_vqs(info, tmp_map);
 
 	bitmap_complement(tmp_map, tmp_map, SVE_VQ_MAX);
-	if (bitmap_intersects(tmp_map, sve_vq_map, SVE_VQ_MAX)) {
-		pr_warn("SVE: cpu%d: Required vector length(s) missing\n",
-			smp_processor_id());
+	if (bitmap_intersects(tmp_map, info->vq_map, SVE_VQ_MAX)) {
+		pr_warn("%s: cpu%d: Required vector length(s) missing\n",
+			info->name, smp_processor_id());
 		return -EINVAL;
 	}
 
@@ -788,7 +803,7 @@ int sve_verify_vq_map(void)
 	/* Recover the set of supported VQs: */
 	bitmap_complement(tmp_map, tmp_map, SVE_VQ_MAX);
 	/* Find VQs supported that are not globally supported: */
-	bitmap_andnot(tmp_map, tmp_map, sve_vq_map, SVE_VQ_MAX);
+	bitmap_andnot(tmp_map, tmp_map, info->vq_map, SVE_VQ_MAX);
 
 	/* Find the lowest such VQ, if any: */
 	b = find_last_bit(tmp_map, SVE_VQ_MAX);
@@ -799,9 +814,9 @@ int sve_verify_vq_map(void)
 	 * Mismatches above sve_max_virtualisable_vl are fine, since
 	 * no guest is allowed to configure ZCR_EL2.LEN to exceed this:
 	 */
-	if (sve_vl_from_vq(__bit_to_vq(b)) <= sve_max_virtualisable_vl) {
-		pr_warn("SVE: cpu%d: Unsupported vector length(s) present\n",
-			smp_processor_id());
+	if (sve_vl_from_vq(__bit_to_vq(b)) <= info->max_virtualisable_vl) {
+		pr_warn("%s: cpu%d: Unsupported vector length(s) present\n",
+			info->name, smp_processor_id());
 		return -EINVAL;
 	}
 
@@ -810,6 +825,8 @@ int sve_verify_vq_map(void)
 
 static void __init sve_efi_setup(void)
 {
+	struct vl_info *info = &vl_info[ARM64_VEC_SVE];
+
 	if (!IS_ENABLED(CONFIG_EFI))
 		return;
 
@@ -818,11 +835,11 @@ static void __init sve_efi_setup(void)
 	 * 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))
+	if (!sve_vl_valid(info->max_vl))
 		goto fail;
 
 	efi_sve_state = __alloc_percpu(
-		SVE_SIG_REGS_SIZE(sve_vq_from_vl(sve_max_vl)), SVE_VQ_BYTES);
+		SVE_SIG_REGS_SIZE(sve_vq_from_vl(info->max_vl)), SVE_VQ_BYTES);
 	if (!efi_sve_state)
 		goto fail;
 
@@ -871,6 +888,7 @@ u64 read_zcr_features(void)
 
 void __init sve_setup(void)
 {
+	struct vl_info *info = &vl_info[ARM64_VEC_SVE];
 	u64 zcr;
 	DECLARE_BITMAP(tmp_map, SVE_VQ_MAX);
 	unsigned long b;
@@ -883,49 +901,52 @@ void __init sve_setup(void)
 	 * so sve_vq_map must have at least SVE_VQ_MIN set.
 	 * If something went wrong, at least try to patch it up:
 	 */
-	if (WARN_ON(!test_bit(__vq_to_bit(SVE_VQ_MIN), sve_vq_map)))
-		set_bit(__vq_to_bit(SVE_VQ_MIN), sve_vq_map);
+	if (WARN_ON(!test_bit(__vq_to_bit(SVE_VQ_MIN), info->vq_map)))
+		set_bit(__vq_to_bit(SVE_VQ_MIN), info->vq_map);
 
 	zcr = read_sanitised_ftr_reg(SYS_ZCR_EL1);
-	sve_max_vl = sve_vl_from_vq((zcr & ZCR_ELx_LEN_MASK) + 1);
+	info->max_vl = sve_vl_from_vq((zcr & ZCR_ELx_LEN_MASK) + 1);
 
 	/*
 	 * Sanity-check that the max VL we determined through CPU features
 	 * corresponds properly to sve_vq_map.  If not, do our best:
 	 */
-	if (WARN_ON(sve_max_vl != find_supported_sve_vector_length(sve_max_vl)))
-		sve_max_vl = find_supported_sve_vector_length(sve_max_vl);
+	if (WARN_ON(info->max_vl != find_supported_vector_length(ARM64_VEC_SVE,
+								 info->max_vl)))
+		info->max_vl = find_supported_vector_length(ARM64_VEC_SVE,
+							    info->max_vl);
 
 	/*
 	 * For the default VL, pick the maximum supported value <= 64.
 	 * VL == 64 is guaranteed not to grow the signal frame.
 	 */
-	set_sve_default_vl(find_supported_sve_vector_length(64));
+	set_sve_default_vl(find_supported_vector_length(ARM64_VEC_SVE, 64));
 
-	bitmap_andnot(tmp_map, sve_vq_partial_map, sve_vq_map,
+	bitmap_andnot(tmp_map, info->vq_partial_map, info->vq_map,
 		      SVE_VQ_MAX);
 
 	b = find_last_bit(tmp_map, SVE_VQ_MAX);
 	if (b >= SVE_VQ_MAX)
 		/* No non-virtualisable VLs found */
-		sve_max_virtualisable_vl = SVE_VQ_MAX;
+		info->max_virtualisable_vl = SVE_VQ_MAX;
 	else if (WARN_ON(b == SVE_VQ_MAX - 1))
 		/* No virtualisable VLs?  This is architecturally forbidden. */
-		sve_max_virtualisable_vl = SVE_VQ_MIN;
+		info->max_virtualisable_vl = SVE_VQ_MIN;
 	else /* b + 1 < SVE_VQ_MAX */
-		sve_max_virtualisable_vl = sve_vl_from_vq(__bit_to_vq(b + 1));
+		info->max_virtualisable_vl = sve_vl_from_vq(__bit_to_vq(b + 1));
 
-	if (sve_max_virtualisable_vl > sve_max_vl)
-		sve_max_virtualisable_vl = sve_max_vl;
+	if (info->max_virtualisable_vl > info->max_vl)
+		info->max_virtualisable_vl = info->max_vl;
 
-	pr_info("SVE: maximum available vector length %u bytes per vector\n",
-		sve_max_vl);
-	pr_info("SVE: default vector length %u bytes per vector\n",
-		get_sve_default_vl());
+	pr_info("%s: maximum available vector length %u bytes per vector\n",
+		info->name, info->max_vl);
+	pr_info("%s: default vector length %u bytes per vector\n",
+		info->name, get_sve_default_vl());
 
 	/* KVM decides whether to support mismatched systems. Just warn here: */
-	if (sve_max_virtualisable_vl < sve_max_vl)
-		pr_warn("SVE: unvirtualisable vector lengths present\n");
+	if (sve_max_virtualisable_vl() < sve_max_vl())
+		pr_warn("%s: unvirtualisable vector lengths present\n",
+			info->name);
 
 	sve_efi_setup();
 }
@@ -1087,7 +1108,7 @@ void fpsimd_flush_thread(void)
 		if (WARN_ON(!sve_vl_valid(vl)))
 			vl = SVE_VL_MIN;
 
-		supported_vl = find_supported_sve_vector_length(vl);
+		supported_vl = find_supported_vector_length(ARM64_VEC_SVE, vl);
 		if (WARN_ON(supported_vl != vl))
 			vl = supported_vl;
 
@@ -1376,7 +1397,7 @@ void __efi_fpsimd_begin(void)
 
 			__this_cpu_write(efi_sve_state_used, true);
 
-			sve_save_state(sve_state + sve_ffr_offset(sve_max_vl),
+			sve_save_state(sve_state + sve_ffr_offset(sve_max_vl()),
 				       &this_cpu_ptr(&efi_fpsimd_state)->fpsr,
 				       true);
 		} else {
@@ -1402,7 +1423,7 @@ void __efi_fpsimd_end(void)
 		    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),
+			sve_load_state(sve_state + sve_ffr_offset(sve_max_vl()),
 				       &this_cpu_ptr(&efi_fpsimd_state)->fpsr,
 				       true,
 				       sve_vq_from_vl(sve_get_vl()) - 1);