[PATCH 25/71] target/arm: Add SVCR

[Richard Henderson]

This cpreg is used to access two new bits of PSTATE
that are not visible via any other mechanism.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 target/arm/cpu.h    |  6 ++++++
 target/arm/helper.c | 13 +++++++++++++
 2 files changed, 19 insertions(+)

diff --git a/target/arm/cpu.h b/target/arm/cpu.h
index 31f812eda7..31b764556c 100644
--- a/target/arm/cpu.h
+++ b/target/arm/cpu.h
@@ -258,6 +258,7 @@ typedef struct CPUArchState {
      *  nRW (also known as M[4]) is kept, inverted, in env->aarch64
      *  DAIF (exception masks) are kept in env->daif
      *  BTYPE is kept in env->btype
+     *  SM and ZA are kept in env->svcr
      *  all other bits are stored in their correct places in env->pstate
      */
     uint32_t pstate;
@@ -292,6 +293,7 @@ typedef struct CPUArchState {
     uint32_t condexec_bits; /* IT bits.  cpsr[15:10,26:25].  */
     uint32_t btype;  /* BTI branch type.  spsr[11:10].  */
     uint64_t daif; /* exception masks, in the bits they are in PSTATE */
+    uint64_t svcr; /* PSTATE.{SM,ZA} in the bits they are in SVCR */
 
     uint64_t elr_el[4]; /* AArch64 exception link regs  */
     uint64_t sp_el[4]; /* AArch64 banked stack pointers */
@@ -1428,6 +1430,10 @@ FIELD(CPTR_EL3, TCPAC, 31, 1)
 #define PSTATE_MODE_EL1t 4
 #define PSTATE_MODE_EL0t 0
 
+/* PSTATE bits that are accessed via SVCR and not stored in SPRS_ELx. */
+FIELD(SVCR, SM, 0, 1)
+FIELD(SVCR, ZA, 1, 1)
+
 /* Write a new value to v7m.exception, thus transitioning into or out
  * of Handler mode; this may result in a change of active stack pointer.
  */
diff --git a/target/arm/helper.c b/target/arm/helper.c
index 98de2c797f..366420385a 100644
--- a/target/arm/helper.c
+++ b/target/arm/helper.c
@@ -6353,11 +6353,24 @@ static CPAccessResult access_tpidr2(CPUARMState *env, 
const ARMCPRegInfo *ri,
     return CP_ACCESS_OK;
 }
 
+static void svcr_write(CPUARMState *env, const ARMCPRegInfo *ri,
+                       uint64_t value)
+{
+    value &= R_SVCR_SM_MASK | R_SVCR_ZA_MASK;
+    /* TODO: Side effects. */
+    env->svcr = value;
+}
+
 static const ARMCPRegInfo sme_reginfo[] = {
     { .name = "TPIDR2_EL0", .state = ARM_CP_STATE_AA64,
       .opc0 = 3, .opc1 = 3, .crn = 13, .crm = 0, .opc2 = 5,
       .access = PL0_RW, .accessfn = access_tpidr2,
       .fieldoffset = offsetof(CPUARMState, cp15.tpidr2_el0) },
+    { .name = "SVCR", .state = ARM_CP_STATE_AA64,
+      .opc0 = 3, .opc1 = 3, .crn = 4, .crm = 2, .opc2 = 2,
+      .access = PL0_RW, .type = ARM_CP_SME,
+      .fieldoffset = offsetof(CPUARMState, svcr),
+      .writefn = svcr_write, .raw_writefn = raw_write },
 };
 #endif /* TARGET_AARCH64 */
 
-- 
2.34.1