[PATCH 2/3] KVM: arm64: selftests: Remove ARM64_FEATURE_FIELD_BITS and its last user

[Ben Horgan]

ARM64_FEATURE_FIELD_BITS is set to 4 but not all ID register fields are 4
bits. See for instance ID_AA64SMFR0_EL1. The last user of this define,
ARM64_FEATURE_FIELD_BITS, is the set_id_regs selftest. Its logic assumes
the fields aren't a single bits; assert that's the case and stop using the
define. As there are no more users, ARM64_FEATURE_FIELD_BITS is removed.

Signed-off-by: Ben Horgan <ben.horgan at arm.com>
---
 arch/arm64/include/asm/sysreg.h                 | 2 --
 tools/testing/selftests/kvm/arm64/set_id_regs.c | 8 ++++++--
 2 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysreg.h
index 6455db1b54fd..d9aa76d08e13 100644
--- a/arch/arm64/include/asm/sysreg.h
+++ b/arch/arm64/include/asm/sysreg.h
@@ -1129,8 +1129,6 @@
 #define gicr_insn(insn)			read_sysreg_s(GICV5_OP_GICR_##insn)
 #define gic_insn(v, insn)		write_sysreg_s(v, GICV5_OP_GIC_##insn)
 
-#define ARM64_FEATURE_FIELD_BITS	4
-
 #ifdef __ASSEMBLY__
 
 	.macro	mrs_s, rt, sreg
diff --git a/tools/testing/selftests/kvm/arm64/set_id_regs.c b/tools/testing/selftests/kvm/arm64/set_id_regs.c
index 6878ee23310e..a0b81b627037 100644
--- a/tools/testing/selftests/kvm/arm64/set_id_regs.c
+++ b/tools/testing/selftests/kvm/arm64/set_id_regs.c
@@ -268,7 +268,9 @@ static void guest_code(void)
 /* Return a safe value to a given ftr_bits an ftr value */
 uint64_t get_safe_value(const struct reg_ftr_bits *ftr_bits, uint64_t ftr)
 {
-	uint64_t ftr_max = GENMASK_ULL(ARM64_FEATURE_FIELD_BITS - 1, 0);
+	uint64_t ftr_max = ftr_bits->mask >> ftr_bits->shift;
+
+	TEST_ASSERT(ftr_max > 1, "This test doesn't support single bit features");
 
 	if (ftr_bits->sign == FTR_UNSIGNED) {
 		switch (ftr_bits->type) {
@@ -320,7 +322,9 @@ uint64_t get_safe_value(const struct reg_ftr_bits *ftr_bits, uint64_t ftr)
 /* Return an invalid value to a given ftr_bits an ftr value */
 uint64_t get_invalid_value(const struct reg_ftr_bits *ftr_bits, uint64_t ftr)
 {
-	uint64_t ftr_max = GENMASK_ULL(ARM64_FEATURE_FIELD_BITS - 1, 0);
+	uint64_t ftr_max = ftr_bits->mask >> ftr_bits->shift;
+
+	TEST_ASSERT(ftr_max > 1, "This test doesn't support single bit features");
 
 	if (ftr_bits->sign == FTR_UNSIGNED) {
 		switch (ftr_bits->type) {
-- 
2.43.0