Re: [Qemu-devel] [PATCH v3 11/32] target-arm: add async excp target_el&mode function

["Aggeler Fabian" <aggelerf@student.ethz.ch>]

On 12 Jun 2014, at 23:56, Greg Bellows <greg.bellows@linaro.org<mailto:greg.bellows@linaro.org>> wrote:




On 10 June 2014 18:54, Fabian Aggeler <aggelerf@ethz.ch<mailto:aggelerf@ethz.ch>> wrote:
Adds a dedicated function for IRQ and FIQ exceptions to determine
target_el and mode (Aarch32) according to tables in ARM ARMv8 and
ARM ARM v7.

Signed-off-by: Fabian Aggeler <aggelerf@ethz.ch<mailto:aggelerf@ethz.ch>>
---
 target-arm/cpu.h    |   3 ++
 target-arm/helper.c | 137 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 140 insertions(+)

diff --git a/target-arm/cpu.h b/target-arm/cpu.h
index b786a5a..52e679f 100644
--- a/target-arm/cpu.h
+++ b/target-arm/cpu.h
@@ -768,6 +768,9 @@ static inline bool arm_el_is_aa64(CPUARMState *env, int el)

 void arm_cpu_list(FILE *f, fprintf_function cpu_fprintf);
 unsigned int arm_excp_target_el(CPUState *cs, unsigned int excp_idx);
+inline uint32_t arm_phys_excp_target_el(CPUState *cs, uint32_t *target_mode,
+                                        uint32_t excp_idx, uint32_t cur_el,
+                                        bool secure);

 /* Interface between CPU and Interrupt controller.  */
 void armv7m_nvic_set_pending(void *opaque, int irq);
diff --git a/target-arm/helper.c b/target-arm/helper.c
index 5822353..8333b52 100644
--- a/target-arm/helper.c
+++ b/target-arm/helper.c
@@ -3224,6 +3224,21 @@ uint32_t HELPER(get_r13_banked)(CPUARMState *env, uint32_t mode)
     return 0;
 }

+inline uint32_t arm_phys_excp_target_el(CPUState *cs, uint32_t *target_mode,
+                                        uint32_t excp_idx, uint32_t cur_el,
+                                        bool secure)
+{
+    switch (excp_idx) {
+    case EXCP_IRQ:
+        *target_mode = ARM_CPU_MODE_IRQ;
+        break;
+    case EXCP_FIQ:
+        *target_mode = ARM_CPU_MODE_FIQ;
+        break;
+    }
+    return 1;
+}
+
 unsigned int arm_excp_target_el(CPUState *cs, unsigned int excp_idx)
 {
     return 1;
@@ -3285,6 +3300,128 @@ void switch_mode(CPUARMState *env, int mode)
 }

 /*
+ * Determine the target EL for physical exceptions
+ */
+inline uint32_t arm_phys_excp_target_el(CPUState *cs, uint32_t *target_mode,
+                                        uint32_t excp_idx, uint32_t cur_el,
+                                        bool secure)
+{
+    CPUARMState *env = cs->env_ptr;
+    uint32_t target_el = 1;
+    uint32_t excp_mode = 0;
+
+    bool scr_routing = 0; /* IRQ, FIQ, EA */
+    bool hcr_routing = 0; /* IMO, FMO, AMO */
+
+    switch (excp_idx) {
+    case EXCP_IRQ:
+        scr_routing = (env->cp15.scr_el3 & SCR_IRQ);
+        hcr_routing = (env->cp15.hcr_el2 & HCR_IMO);
+        excp_mode = ARM_CPU_MODE_IRQ;
+        break;
+    case EXCP_FIQ:
+        scr_routing = (env->cp15.scr_el3 & SCR_FIQ);
+        hcr_routing = (env->cp15.hcr_el2 & HCR_FMO);
+        excp_mode = ARM_CPU_MODE_FIQ;
+    }
+
+    /* If HCR.TGE is set all exceptions that would be routed to EL1 are
+     * routed to EL2 (in non-secure world).
+     */
+    if (arm_feature(env, ARM_FEATURE_EL2) && (env->cp15.hcr_el2 & HCR_TGE)) {
+        hcr_routing = 1;
+    }
+
+    /* Determine target EL according to ARM ARMv8 tables G1-15 and G1-16 */
+    if (arm_el_is_aa64(env, 3)) {
+        /* EL3 in Aarch64 */
+        if (scr_routing) {
+            /* IRQ|FIQ|EA == 1 */
+            target_el = 3;
+        } else {
+            if (hcr_routing) {
+                /* IRQ|FIQ|EA == 0
+                 * IMO|FMO|AMO == 1 */
+                if (secure) {
+                    /* Secure */
+                    target_el = 1;
+                    if (!arm_el_is_aa64(env, 1)) {
+                        /* EL1 using Aarch32 */
+                        *target_mode = ARM_CPU_MODE_ABT;
+                    }
+                } else if (cur_el < 2) {
+                    /* Non-Secure goes to EL2 */
+                    target_el = 2;
+                    if (!arm_el_is_aa64(env, 2)) {
+                        /* EL2 using Aarch32 */
+                        *target_mode = ARM_CPU_MODE_HYP;
+                    }
+                }
+            } else if (env->cp15.scr_el3 & SCR_RW) {
+                /* IRQ|FIQ|EA == 0
+                 * IMO|FMO|AMO == 0
+                 * RW == 1 (Next lower level is Aarch64)
+                 */
+                if (cur_el < 2) {
+                    target_el = 1;
+                } else {
+                    /* Interrupt not taken but remains pending */
+                }
+            } else {
+                /* IRQ|FIQ|EA == 0
+                 * IMO|FMO|AMO == 0
+                 * RW == 0 (Next lower level is Aarch64)
+                 */
+                if (cur_el < 2) {
+                    target_el = 1;
+                    *target_mode = ARM_CPU_MODE_ABT;

According to the aforementioned tables, the target mode should be excp_mode, not always abort.

True, this is wrong and should be excp_mode, as you said.


+                } else if (cur_el == 2) {
+                    target_el = 2;
+                    *target_mode = ARM_CPU_MODE_HYP;
+                } else {
+                    /* Interrupt not taken but remains pending */
+                }
+            }
+        }
+    } else {
+        /* EL3 in Aarch32 */
+        if (scr_routing) {
+            /* IRQ|FIQ|EA == 1 */
+            target_el = 3;
+            *target_mode = ARM_CPU_MODE_MON;
+        } else {
+            if (hcr_routing) {
+                /* IRQ|FIQ|EA == 0
+                 * IMO|FMO|AMO == 1
+                 */
+                if (secure) {
+                    target_el = 3;
+                    *target_mode = excp_mode;
+                } else {
+                    target_el = 2;
+                    *target_mode = ARM_CPU_MODE_HYP;
+                }
+            } else {
+                /* IRQ|FIQ|EA == 0
+                 * IMO|FMO|AMO == 0
+                 */
+                if (cur_el < 2) {
+                    target_el = 1;
+                    *target_mode = excp_mode;
+                } else if (cur_el == 2) {
+                    target_el = 2;
+                    *target_mode = ARM_CPU_MODE_HYP;
+                } else if (secure) {
+                    target_el = 3;
+                    *target_mode = excp_mode;
+                }
+            }
+        }
+    }
+    return target_el;
+}
+
+/*
  * Determine the target EL for a given exception type.
  */
 unsigned int arm_excp_target_el(CPUState *cs, unsigned int excp_idx)
--
1.8.3.2