[PATCH v3 16/21] linux-user/aarch64: Pass syndrome to EXC_*_ABORT

From: Richard Henderson <richard.henderson@linaro.org>
To: qemu-devel@nongnu.org
Cc: peter.maydell@linaro.org, qemu-arm@nongnu.org
Subject: [PATCH v3 16/21] linux-user/aarch64: Pass syndrome to EXC_*_ABORT
Date: Fri, 15 Jan 2021 12:46:40 -1000	[thread overview]
Message-ID: <20210115224645.1196742-17-richard.henderson@linaro.org> (raw)
In-Reply-To: <20210115224645.1196742-1-richard.henderson@linaro.org>

A proper syndrome is required to fill in the proper si_code.
Use page_get_flags to determine permission vs translation for user-only.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
v3: Use syndrome.h, arm_deliver_fault.
---
 linux-user/aarch64/cpu_loop.c | 24 +++++++++++++++++++++---
 target/arm/tlb_helper.c       | 15 +++++++++------
 2 files changed, 30 insertions(+), 9 deletions(-)

diff --git a/linux-user/aarch64/cpu_loop.c b/linux-user/aarch64/cpu_loop.c
index bbe9fefca8..7811440c68 100644
--- a/linux-user/aarch64/cpu_loop.c
+++ b/linux-user/aarch64/cpu_loop.c
@@ -22,6 +22,7 @@
 #include "qemu.h"
 #include "cpu_loop-common.h"
 #include "qemu/guest-random.h"
+#include "target/arm/syndrome.h"
 
 #define get_user_code_u32(x, gaddr, env)                \
     ({ abi_long __r = get_user_u32((x), (gaddr));       \
@@ -75,7 +76,7 @@
 void cpu_loop(CPUARMState *env)
 {
     CPUState *cs = env_cpu(env);
-    int trapnr;
+    int trapnr, ec, fsc;
     abi_long ret;
     target_siginfo_t info;
 
@@ -116,9 +117,26 @@ void cpu_loop(CPUARMState *env)
         case EXCP_DATA_ABORT:
             info.si_signo = TARGET_SIGSEGV;
             info.si_errno = 0;
-            /* XXX: check env->error_code */
-            info.si_code = TARGET_SEGV_MAPERR;
             info._sifields._sigfault._addr = env->exception.vaddress;
+
+            /* We should only arrive here with EC in {DATAABORT, INSNABORT}. */
+            ec = syn_get_ec(env->exception.syndrome);
+            assert(ec == EC_DATAABORT || ec == EC_INSNABORT);
+
+            /* Both EC have the same format for FSC, or close enough. */
+            fsc = extract32(env->exception.syndrome, 0, 6);
+            switch (fsc) {
+            case 0x04 ... 0x07: /* Translation fault, level {0-3} */
+                info.si_code = TARGET_SEGV_MAPERR;
+                break;
+            case 0x09 ... 0x0b: /* Access flag fault, level {1-3} */
+            case 0x0d ... 0x0f: /* Permission fault, level {1-3} */
+                info.si_code = TARGET_SEGV_ACCERR;
+                break;
+            default:
+                g_assert_not_reached();
+            }
+
             queue_signal(env, info.si_signo, QEMU_SI_FAULT, &info);
             break;
         case EXCP_DEBUG:
diff --git a/target/arm/tlb_helper.c b/target/arm/tlb_helper.c
index b35dc8a011..31015749fd 100644
--- a/target/arm/tlb_helper.c
+++ b/target/arm/tlb_helper.c
@@ -151,21 +151,24 @@ bool arm_cpu_tlb_fill(CPUState *cs, vaddr address, int size,
                       bool probe, uintptr_t retaddr)
 {
     ARMCPU *cpu = ARM_CPU(cs);
+    ARMMMUFaultInfo fi = {};
 
 #ifdef CONFIG_USER_ONLY
-    cpu->env.exception.vaddress = address;
-    if (access_type == MMU_INST_FETCH) {
-        cs->exception_index = EXCP_PREFETCH_ABORT;
+    int flags = page_get_flags(useronly_clean_ptr(address));
+    if (flags & PAGE_VALID) {
+        fi.type = ARMFault_Permission;
     } else {
-        cs->exception_index = EXCP_DATA_ABORT;
+        fi.type = ARMFault_Translation;
     }
-    cpu_loop_exit_restore(cs, retaddr);
+
+    /* 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;
     MemTxAttrs attrs = {};
-    ARMMMUFaultInfo fi = {};
     ARMCacheAttrs cacheattrs = {};
 
     /*
-- 
2.25.1


