For register names that are unsupported by the assembler or the ones
without architectural names, add the macros write_sysreg_s and
read_sysreg_s to support them.
The functionality is derived from kvm-unit-tests and kernel's
arch/arm64/include/asm/sysreg.h.
Signed-off-by: Raghavendra Rao Ananta <rananta@xxxxxxxxxx>
---
.../selftests/kvm/include/aarch64/processor.h | 61 +++++++++++++++++++
1 file changed, 61 insertions(+)
diff --git a/tools/testing/selftests/kvm/include/aarch64/processor.h b/tools/testing/selftests/kvm/include/aarch64/processor.h
index 3cbaf5c1e26b..082cc97ad8d3 100644
--- a/tools/testing/selftests/kvm/include/aarch64/processor.h
+++ b/tools/testing/selftests/kvm/include/aarch64/processor.h
@@ -118,6 +118,67 @@ void vm_install_exception_handler(struct kvm_vm *vm,
void vm_install_sync_handler(struct kvm_vm *vm,
int vector, int ec, handler_fn handler);
+/*
+ * ARMv8 ARM reserves the following encoding for system registers:
+ * (Ref: ARMv8 ARM, Section: "System instruction class encoding overview",
+ * C5.2, version:ARM DDI 0487A.f)
+ * [20-19] : Op0
+ * [18-16] : Op1
+ * [15-12] : CRn
+ * [11-8] : CRm
+ * [7-5] : Op2
+ */
+#define Op0_shift 19
+#define Op0_mask 0x3
+#define Op1_shift 16
+#define Op1_mask 0x7
+#define CRn_shift 12
+#define CRn_mask 0xf
+#define CRm_shift 8
+#define CRm_mask 0xf
+#define Op2_shift 5
+#define Op2_mask 0x7
+
+/*
+ * When accessed from guests, the ARM64_SYS_REG() doesn't work since it
+ * generates a different encoding for additional KVM processing, and is
+ * only suitable for userspace to access the register via ioctls.
+ * Hence, define a 'pure' sys_reg() here to generate the encodings as per spec.
+ */
+#define sys_reg(op0, op1, crn, crm, op2) \
+ (((op0) << Op0_shift) | ((op1) << Op1_shift) | \
+ ((crn) << CRn_shift) | ((crm) << CRm_shift) | \
+ ((op2) << Op2_shift))
+
+asm(
+" .irp num,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30\n"
+" .equ .L__reg_num_x\\num, \\num\n"
+" .endr\n"
+" .equ .L__reg_num_xzr, 31\n"
+"\n"
+" .macro mrs_s, rt, sreg\n"
+" .inst 0xd5200000|(\\sreg)|(.L__reg_num_\\rt)\n"
+" .endm\n"
+"\n"
+" .macro msr_s, sreg, rt\n"
+" .inst 0xd5000000|(\\sreg)|(.L__reg_num_\\rt)\n"
+" .endm\n"
+);
+
+/*
+ * read_sysreg_s() and write_sysreg_s()'s 'reg' has to be encoded via sys_reg()
+ */
+#define read_sysreg_s(reg) ({ \
+ u64 __val; \
+ asm volatile("mrs_s %0, "__stringify(reg) : "=r" (__val)); \
+ __val; \
+})
+
+#define write_sysreg_s(reg, val) do { \
+ u64 __val = (u64)val; \
+ asm volatile("msr_s "__stringify(reg) ", %x0" : : "rZ" (__val));\
+} while (0)
+
#define write_sysreg(reg, val) \
({ \
u64 __val = (u64)(val); \
--
2.33.0.153.gba50c8fa24-goog
