target/arm: Implement arm_cpu_record_sigsegv

Because of the complexity of setting ESR, continue to use
arm_deliver_fault.  This means we cannot remove the code
within cpu_loop that decodes EXCP_DATA_ABORT and
EXCP_PREFETCH_ABORT.

But using the new hook means that we don't have to do the
page_get_flags check manually, and we'll be able to restrict
the tlb_fill hook to sysemu later.

Reviewed-by: Warner Losh <imp@bsdimp.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

4 files changed, 33 insertions, 21 deletions

diff --git a/target/arm/cpu.c b/target/arm/cpu.c
index 641a8c2d3d..7a18a58ca0 100644
--- a/target/arm/cpu.c
+++ b/target/arm/cpu.c
@@ -2031,10 +2031,12 @@ static const struct SysemuCPUOps arm_sysemu_ops = {
 static const struct TCGCPUOps arm_tcg_ops = {
     .initialize = arm_translate_init,
     .synchronize_from_tb = arm_cpu_synchronize_from_tb,
-    .tlb_fill = arm_cpu_tlb_fill,
     .debug_excp_handler = arm_debug_excp_handler,
 
-#if !defined(CONFIG_USER_ONLY)
+#ifdef CONFIG_USER_ONLY
+    .record_sigsegv = arm_cpu_record_sigsegv,
+#else
+    .tlb_fill = arm_cpu_tlb_fill,
     .cpu_exec_interrupt = arm_cpu_exec_interrupt,
     .do_interrupt = arm_cpu_do_interrupt,
     .do_transaction_failed = arm_cpu_do_transaction_failed,
diff --git a/target/arm/cpu_tcg.c b/target/arm/cpu_tcg.c
index 0d5adccf1a..7b3bea2fbb 100644
--- a/target/arm/cpu_tcg.c
+++ b/target/arm/cpu_tcg.c
@@ -898,10 +898,12 @@ static void pxa270c5_initfn(Object *obj)
 static const struct TCGCPUOps arm_v7m_tcg_ops = {
     .initialize = arm_translate_init,
     .synchronize_from_tb = arm_cpu_synchronize_from_tb,
-    .tlb_fill = arm_cpu_tlb_fill,
     .debug_excp_handler = arm_debug_excp_handler,
 
-#if !defined(CONFIG_USER_ONLY)
+#ifdef CONFIG_USER_ONLY
+    .record_sigsegv = arm_cpu_record_sigsegv,
+#else
+    .tlb_fill = arm_cpu_tlb_fill,
     .cpu_exec_interrupt = arm_v7m_cpu_exec_interrupt,
     .do_interrupt = arm_v7m_cpu_do_interrupt,
     .do_transaction_failed = arm_cpu_do_transaction_failed,
diff --git a/target/arm/internals.h b/target/arm/internals.h
index 3612107ab2..5a7aaf0f51 100644
--- a/target/arm/internals.h
+++ b/target/arm/internals.h
@@ -544,9 +544,15 @@ static inline bool arm_extabort_type(MemTxResult result)
     return result != MEMTX_DECODE_ERROR;
 }
 
+#ifdef CONFIG_USER_ONLY
+void arm_cpu_record_sigsegv(CPUState *cpu, vaddr addr,
+                            MMUAccessType access_type,
+                            bool maperr, uintptr_t ra);
+#else
 bool arm_cpu_tlb_fill(CPUState *cs, vaddr address, int size,
                       MMUAccessType access_type, int mmu_idx,
                       bool probe, uintptr_t retaddr);
+#endif
 
 static inline int arm_to_core_mmu_idx(ARMMMUIdx mmu_idx)
 {
diff --git a/target/arm/tlb_helper.c b/target/arm/tlb_helper.c
index 3107f9823e..dc5860180f 100644
--- a/target/arm/tlb_helper.c
+++ b/target/arm/tlb_helper.c
@@ -147,28 +147,12 @@ void arm_cpu_do_transaction_failed(CPUState *cs, hwaddr physaddr,
     arm_deliver_fault(cpu, addr, access_type, mmu_idx, &fi);
 }
 
-#endif /* !defined(CONFIG_USER_ONLY) */
-
 bool arm_cpu_tlb_fill(CPUState *cs, vaddr address, int size,
                       MMUAccessType access_type, int mmu_idx,
                       bool probe, uintptr_t retaddr)
 {
     ARMCPU *cpu = ARM_CPU(cs);
     ARMMMUFaultInfo fi = {};
-
-#ifdef CONFIG_USER_ONLY
-    int flags = page_get_flags(useronly_clean_ptr(address));
-    if (flags & PAGE_VALID) {
-        fi.type = ARMFault_Permission;
-    } else {
-        fi.type = ARMFault_Translation;
-    }
-    fi.level = 3;
-
-    /* now we have a real cpu fault */
-    cpu_restore_state(cs, retaddr, true);
-    arm_deliver_fault(cpu, address, access_type, mmu_idx, &fi);
-#else
     hwaddr phys_addr;
     target_ulong page_size;
     int prot, ret;
@@ -210,5 +194,23 @@ bool arm_cpu_tlb_fill(CPUState *cs, vaddr address, int size,
         cpu_restore_state(cs, retaddr, true);
         arm_deliver_fault(cpu, address, access_type, mmu_idx, &fi);
     }
-#endif
 }
+#else
+void arm_cpu_record_sigsegv(CPUState *cs, vaddr addr,
+                            MMUAccessType access_type,
+                            bool maperr, uintptr_t ra)
+{
+    ARMMMUFaultInfo fi = {
+        .type = maperr ? ARMFault_Translation : ARMFault_Permission,
+        .level = 3,
+    };
+    ARMCPU *cpu = ARM_CPU(cs);
+
+    /*
+     * We report both ESR and FAR to signal handlers.
+     * For now, it's easiest to deliver the fault normally.
+     */
+    cpu_restore_state(cs, ra, true);
+    arm_deliver_fault(cpu, addr, access_type, MMU_USER_IDX, &fi);
+}
+#endif /* !defined(CONFIG_USER_ONLY) */