diff mbox

[PACTH,v4,3/6] target-arm: add hvc and smc exception emulation handling infrastructure

Message ID 1410332571-10544-4-git-send-email-ard.biesheuvel@linaro.org
State New
Headers show

Commit Message

Ard Biesheuvel Sept. 10, 2014, 7:02 a.m. UTC
From: Rob Herring <rob.herring@linaro.org>

Add the infrastructure to handle and emulate hvc and smc exceptions.
This will enable emulation of things such as PSCI calls. This commit
does not change the behavior and will exit with unknown exception.

Signed-off-by: Rob Herring <rob.herring@linaro.org>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
 target-arm/cpu-qom.h       |  3 +++
 target-arm/cpu.h           |  2 ++
 target-arm/helper-a64.c    | 16 +++++++++++++
 target-arm/helper.c        | 23 ++++++++++++++++++
 target-arm/internals.h     | 20 ++++++++++++++++
 target-arm/translate-a64.c | 35 ++++++++++++++++++++-------
 target-arm/translate.c     | 59 +++++++++++++++++++++++++++++++++++++---------
 target-arm/translate.h     |  2 ++
 8 files changed, 140 insertions(+), 20 deletions(-)

Comments

Peter Maydell Sept. 26, 2014, 10:17 a.m. UTC | #1
On 10 September 2014 08:02, Ard Biesheuvel <ard.biesheuvel@linaro.org> wrote:
> From: Rob Herring <rob.herring@linaro.org>
>
> Add the infrastructure to handle and emulate hvc and smc exceptions.
> This will enable emulation of things such as PSCI calls. This commit
> does not change the behavior and will exit with unknown exception.
>
> Signed-off-by: Rob Herring <rob.herring@linaro.org>
> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>

> diff --git a/target-arm/helper-a64.c b/target-arm/helper-a64.c
> index 89b913ee9396..1f8072ab141b 100644
> --- a/target-arm/helper-a64.c
> +++ b/target-arm/helper-a64.c
> @@ -485,6 +485,22 @@ void aarch64_cpu_do_interrupt(CPUState *cs)
>      case EXCP_FIQ:
>          addr += 0x100;
>          break;
> +    case EXCP_HVC:
> +        if (arm_cpu_do_hvc(cs)) {
> +            return;
> +        }
> +        /* Treat as unallocated encoding */
> +        qemu_log_mask(LOG_GUEST_ERROR, "HVC not implemented on this CPU\n");
> +        env->exception.syndrome = syn_uncategorized();
> +        break;
> +    case EXCP_SMC:
> +        if (arm_cpu_do_smc(cs)) {
> +            return;
> +        }
> +        /* Treat as unallocated encoding */
> +        qemu_log_mask(LOG_GUEST_ERROR, "SMC not implemented on this CPU\n");
> +        env->exception.syndrome = syn_uncategorized();
> +        break;


Looking again at this there are some issues with this,
notably that we don't do anything to ensure that the PC
is pointing at the instruction we're claiming to be UNDEF
rather than just after it.

The best approach seems to me to be to figure out at
translate time whether we're going to call this SMC
UNDEF or not.

We also seem to only generate the SMC and HVC exception
if the CPU has the FEATURE_EL2/3 bit set, which confuses
me because our CPUs don't set that and so I'm not sure
how this works at all...

I think the best way to fix this is going to be to rebase
this on top of Edgar's EL2/EL3 support patches, which
already deal with most of those problems (albeit only
for AArch64 currently). I'll do that and send out a
fixed version.

thanks
-- PMM
diff mbox

Patch

diff --git a/target-arm/cpu-qom.h b/target-arm/cpu-qom.h
index eae0a7b9c908..104cc67e82d2 100644
--- a/target-arm/cpu-qom.h
+++ b/target-arm/cpu-qom.h
@@ -192,6 +192,9 @@  extern const struct VMStateDescription vmstate_arm_cpu;
 void register_cp_regs_for_features(ARMCPU *cpu);
 void init_cpreg_list(ARMCPU *cpu);
 
+bool arm_cpu_do_hvc(CPUState *cs);
+bool arm_cpu_do_smc(CPUState *cs);
+
 void arm_cpu_do_interrupt(CPUState *cpu);
 void arm_v7m_cpu_do_interrupt(CPUState *cpu);
 
diff --git a/target-arm/cpu.h b/target-arm/cpu.h
index 51bedc826299..d235929f4c12 100644
--- a/target-arm/cpu.h
+++ b/target-arm/cpu.h
@@ -51,6 +51,8 @@ 
 #define EXCP_EXCEPTION_EXIT  8   /* Return from v7M exception.  */
 #define EXCP_KERNEL_TRAP     9   /* Jumped to kernel code page.  */
 #define EXCP_STREX          10
+#define EXCP_HVC            11
+#define EXCP_SMC            12
 
 #define ARMV7M_EXCP_RESET   1
 #define ARMV7M_EXCP_NMI     2
diff --git a/target-arm/helper-a64.c b/target-arm/helper-a64.c
index 89b913ee9396..1f8072ab141b 100644
--- a/target-arm/helper-a64.c
+++ b/target-arm/helper-a64.c
@@ -485,6 +485,22 @@  void aarch64_cpu_do_interrupt(CPUState *cs)
     case EXCP_FIQ:
         addr += 0x100;
         break;
+    case EXCP_HVC:
+        if (arm_cpu_do_hvc(cs)) {
+            return;
+        }
+        /* Treat as unallocated encoding */
+        qemu_log_mask(LOG_GUEST_ERROR, "HVC not implemented on this CPU\n");
+        env->exception.syndrome = syn_uncategorized();
+        break;
+    case EXCP_SMC:
+        if (arm_cpu_do_smc(cs)) {
+            return;
+        }
+        /* Treat as unallocated encoding */
+        qemu_log_mask(LOG_GUEST_ERROR, "SMC not implemented on this CPU\n");
+        env->exception.syndrome = syn_uncategorized();
+        break;
     default:
         cpu_abort(cs, "Unhandled exception 0x%x\n", cs->exception_index);
     }
diff --git a/target-arm/helper.c b/target-arm/helper.c
index 9c129c8b080c..64bd49ecdaf9 100644
--- a/target-arm/helper.c
+++ b/target-arm/helper.c
@@ -3492,6 +3492,16 @@  void arm_v7m_cpu_do_interrupt(CPUState *cs)
     env->thumb = addr & 1;
 }
 
+bool arm_cpu_do_hvc(CPUState *cs)
+{
+    return false;
+}
+
+bool arm_cpu_do_smc(CPUState *cs)
+{
+    return false;
+}
+
 /* Handle a CPU exception.  */
 void arm_cpu_do_interrupt(CPUState *cs)
 {
@@ -3508,6 +3518,19 @@  void arm_cpu_do_interrupt(CPUState *cs)
 
     /* TODO: Vectored interrupt controller.  */
     switch (cs->exception_index) {
+    case EXCP_HVC:
+        if (arm_cpu_do_hvc(cs)) {
+            return;
+        }
+        qemu_log_mask(LOG_GUEST_ERROR, "HVC not implemented on this CPU\n");
+        goto hvc_unallocated;
+    case EXCP_SMC:
+        if (arm_cpu_do_smc(cs)) {
+            return;
+        }
+        qemu_log_mask(LOG_GUEST_ERROR, "SMC not implemented on this CPU\n");
+    hvc_unallocated:
+        /* Fall through -- treat as unallocated encoding */
     case EXCP_UDEF:
         new_mode = ARM_CPU_MODE_UND;
         addr = 0x04;
diff --git a/target-arm/internals.h b/target-arm/internals.h
index 53c2e3cf3e7e..caab98e6b508 100644
--- a/target-arm/internals.h
+++ b/target-arm/internals.h
@@ -210,6 +210,26 @@  static inline uint32_t syn_aa32_svc(uint32_t imm16, bool is_thumb)
         | (is_thumb ? 0 : ARM_EL_IL);
 }
 
+static inline uint32_t syn_aa64_hvc(uint32_t imm16)
+{
+    return (EC_AA64_HVC << ARM_EL_EC_SHIFT) | ARM_EL_IL | (imm16 & 0xffff);
+}
+
+static inline uint32_t syn_aa32_hvc(uint32_t imm16)
+{
+    return (EC_AA32_HVC << ARM_EL_EC_SHIFT) | ARM_EL_IL | (imm16 & 0xffff);
+}
+
+static inline uint32_t syn_aa64_smc(uint32_t imm16)
+{
+    return (EC_AA64_SMC << ARM_EL_EC_SHIFT) | ARM_EL_IL | (imm16 & 0xffff);
+}
+
+static inline uint32_t syn_aa32_smc(void)
+{
+    return (EC_AA32_SMC << ARM_EL_EC_SHIFT) | ARM_EL_IL;
+}
+
 static inline uint32_t syn_aa64_bkpt(uint32_t imm16)
 {
     return (EC_AA64_BKPT << ARM_EL_EC_SHIFT) | ARM_EL_IL | (imm16 & 0xffff);
diff --git a/target-arm/translate-a64.c b/target-arm/translate-a64.c
index 8e66b6c97282..e5fb775c4a50 100644
--- a/target-arm/translate-a64.c
+++ b/target-arm/translate-a64.c
@@ -1473,20 +1473,37 @@  static void disas_exc(DisasContext *s, uint32_t insn)
 
     switch (opc) {
     case 0:
-        /* SVC, HVC, SMC; since we don't support the Virtualization
-         * or TrustZone extensions these all UNDEF except SVC.
-         */
-        if (op2_ll != 1) {
-            unallocated_encoding(s);
-            break;
-        }
         /* For SVC, HVC and SMC we advance the single-step state
          * machine before taking the exception. This is architecturally
          * mandated, to ensure that single-stepping a system call
          * instruction works properly.
          */
-        gen_ss_advance(s);
-        gen_exception_insn(s, 0, EXCP_SWI, syn_aa64_svc(imm16));
+        switch (op2_ll) {
+        case 1:
+            gen_ss_advance(s);
+            gen_exception_insn(s, 0, EXCP_SWI, syn_aa64_svc(imm16));
+            break;
+        case 2:
+            if (s->current_pl != 0
+                && arm_dc_feature(s, ARM_FEATURE_EL2)) {
+                gen_ss_advance(s);
+                gen_exception_insn(s, 0, EXCP_HVC, syn_aa64_hvc(imm16));
+                break;
+            }
+            unallocated_encoding(s);
+            break;
+        case 3:
+            if (s->current_pl != 0
+                && arm_dc_feature(s, ARM_FEATURE_EL3)) {
+                gen_ss_advance(s);
+                gen_exception_insn(s, 0, EXCP_SMC, syn_aa64_smc(imm16));
+                break;
+            }
+            /* fall through */
+        default:
+            unallocated_encoding(s);
+            break;
+        }
         break;
     case 1:
         if (op2_ll != 0) {
diff --git a/target-arm/translate.c b/target-arm/translate.c
index 2c0b1deaea81..aefe01142762 100644
--- a/target-arm/translate.c
+++ b/target-arm/translate.c
@@ -7871,15 +7871,33 @@  static void disas_arm_insn(CPUARMState * env, DisasContext *s)
         case 7:
         {
             int imm16 = extract32(insn, 0, 4) | (extract32(insn, 8, 12) << 4);
-            /* SMC instruction (op1 == 3)
-               and undefined instructions (op1 == 0 || op1 == 2)
-               will trap */
-            if (op1 != 1) {
+            switch (op1) {
+            case 1:
+                /* bkpt */
+                ARCH(5);
+                gen_exception_insn(s, 4, EXCP_BKPT,
+                                   syn_aa32_bkpt(imm16, false));
+                break;
+            case 2:
+                /* Hypervisor call (v7) */
+                ARCH(7);
+                if (IS_USER(s))
+                    goto illegal_op;
+                s->svc_imm = imm16;
+                gen_set_pc_im(s, s->pc);
+                s->is_jmp = DISAS_HVC;
+                break;
+            case 3:
+                /* Secure monitor call (v6+) */
+                ARCH(6K);
+                if (IS_USER(s))
+                    goto illegal_op;
+                gen_set_pc_im(s, s->pc);
+                s->is_jmp = DISAS_SMC;
+                break;
+            default:
                 goto illegal_op;
             }
-            /* bkpt */
-            ARCH(5);
-            gen_exception_insn(s, 4, EXCP_BKPT, syn_aa32_bkpt(imm16, false));
             break;
         }
         case 0x8: /* signed multiply */
@@ -9709,10 +9727,23 @@  static int disas_thumb2_insn(CPUARMState *env, DisasContext *s, uint16_t insn_hw
                     goto illegal_op;
 
                 if (insn & (1 << 26)) {
-                    /* Secure monitor call (v6Z) */
-                    qemu_log_mask(LOG_UNIMP,
-                                  "arm: unimplemented secure monitor call\n");
-                    goto illegal_op; /* not implemented.  */
+                    if (!(insn & (1 << 20))) {
+                        /* Hypervisor call (v7) */
+                        ARCH(7);
+                        if (IS_USER(s))
+                            goto illegal_op;
+                        s->svc_imm = extract32(insn, 16, 4) << 12 |
+                                     extract32(insn, 0, 12);
+                        gen_set_pc_im(s, s->pc);
+                        s->is_jmp = DISAS_HVC;
+                    } else {
+                        /* Secure monitor call (v6+) */
+                        ARCH(6K);
+                        if (IS_USER(s))
+                            goto illegal_op;
+                        gen_set_pc_im(s, s->pc);
+                        s->is_jmp = DISAS_SMC;
+                    }
                 } else {
                     op = (insn >> 20) & 7;
                     switch (op) {
@@ -11200,6 +11231,12 @@  static inline void gen_intermediate_code_internal(ARMCPU *cpu,
         case DISAS_SWI:
             gen_exception(EXCP_SWI, syn_aa32_svc(dc->svc_imm, dc->thumb));
             break;
+        case DISAS_HVC:
+            gen_exception(EXCP_HVC, syn_aa32_hvc(dc->svc_imm));
+            break;
+        case DISAS_SMC:
+            gen_exception(EXCP_SMC, syn_aa32_smc());
+            break;
         }
         if (dc->condjmp) {
             gen_set_label(dc->condlabel);
diff --git a/target-arm/translate.h b/target-arm/translate.h
index b90d27514d52..50c4d6ef4ab6 100644
--- a/target-arm/translate.h
+++ b/target-arm/translate.h
@@ -82,6 +82,8 @@  static inline int get_mem_index(DisasContext *s)
 #define DISAS_EXC 6
 /* WFE */
 #define DISAS_WFE 7
+#define DISAS_HVC 8
+#define DISAS_SMC 9
 
 #ifdef TARGET_AARCH64
 void a64_translate_init(void);