arm64/fp: Use a struct to pass data to fpsimd_bind_state_to_cpu()

For reasons that are unclear to this reader fpsimd_bind_state_to_cpu()
populates the struct fpsimd_last_state_struct that it uses to store the
active floating point state for KVM guests by passing an argument for
each member of the structure. As the richness of the architecture increases
this is resulting in a function with a rather large number of arguments
which isn't ideal.

Simplify the interface by using the struct directly as the single argument
for the function, renaming it as we lift the definition into the header.
This could be built on further to reduce the work we do adding storage for
new FP state in various places but for now it just simplifies this one
interface.

Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20221115094640.112848-9-broonie@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>

1 files changed, 6 insertions, 28 deletions

diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c
index a66b8640a0a4..de97d2be915b 100644
--- a/arch/arm64/kernel/fpsimd.c
+++ b/arch/arm64/kernel/fpsimd.c
@@ -118,18 +118,8 @@
  *   returned from the 2nd syscall yet, TIF_FOREIGN_FPSTATE is still set so
  *   whatever is in the FPSIMD registers is not saved to memory, but discarded.
  */
-struct fpsimd_last_state_struct {
-	struct user_fpsimd_state *st;
-	void *sve_state;
-	void *za_state;
-	u64 *svcr;
-	unsigned int sve_vl;
-	unsigned int sme_vl;
-	enum fp_type *fp_type;
-	enum fp_type to_save;
-};
 
-static DEFINE_PER_CPU(struct fpsimd_last_state_struct, fpsimd_last_state);
+static DEFINE_PER_CPU(struct cpu_fp_state, fpsimd_last_state);
 
 __ro_after_init struct vl_info vl_info[ARM64_VEC_MAX] = {
 #ifdef CONFIG_ARM64_SVE
@@ -468,7 +458,7 @@ static void task_fpsimd_load(void)
  */
 static void fpsimd_save(void)
 {
-	struct fpsimd_last_state_struct const *last =
+	struct cpu_fp_state const *last =
 		this_cpu_ptr(&fpsimd_last_state);
 	/* set by fpsimd_bind_task_to_cpu() or fpsimd_bind_state_to_cpu() */
 	bool save_sve_regs = false;
@@ -1716,8 +1706,7 @@ void fpsimd_kvm_prepare(void)
  */
 static void fpsimd_bind_task_to_cpu(void)
 {
-	struct fpsimd_last_state_struct *last =
-		this_cpu_ptr(&fpsimd_last_state);
+	struct cpu_fp_state *last = this_cpu_ptr(&fpsimd_last_state);
 
 	WARN_ON(!system_supports_fpsimd());
 	last->st = &current->thread.uw.fpsimd_state;
@@ -1749,25 +1738,14 @@ static void fpsimd_bind_task_to_cpu(void)
 	}
 }
 
-void fpsimd_bind_state_to_cpu(struct user_fpsimd_state *st, void *sve_state,
-			      unsigned int sve_vl, void *za_state,
-			      unsigned int sme_vl, u64 *svcr,
-			      enum fp_type *type, enum fp_type to_save)
+void fpsimd_bind_state_to_cpu(struct cpu_fp_state *state)
 {
-	struct fpsimd_last_state_struct *last =
-		this_cpu_ptr(&fpsimd_last_state);
+	struct cpu_fp_state *last = this_cpu_ptr(&fpsimd_last_state);
 
 	WARN_ON(!system_supports_fpsimd());
 	WARN_ON(!in_softirq() && !irqs_disabled());
 
-	last->st = st;
-	last->svcr = svcr;
-	last->sve_state = sve_state;
-	last->za_state = za_state;
-	last->sve_vl = sve_vl;
-	last->sme_vl = sme_vl;
-	last->fp_type = type;
-	last->to_save = to_save;
+	*last = *state;
 }
 
 /*