Merge remote-tracking branch 'remotes/vivier2/tags/linux-user-for-6.2-pull-request' into staging

Pull request linux-user 20210924

Clean up siginfo_t handling for arm, aarch64

# gpg: Signature made Fri 24 Sep 2021 14:56:12 BST
# gpg:                using RSA key CD2F75DDC8E3A4DC2E4F5173F30C38BD3F2FBE3C
# gpg:                issuer "laurent@vivier.eu"
# gpg: Good signature from "Laurent Vivier <lvivier@redhat.com>" [full]
# gpg:                 aka "Laurent Vivier <laurent@vivier.eu>" [full]
# gpg:                 aka "Laurent Vivier (Red Hat) <lvivier@redhat.com>" [full]
# Primary key fingerprint: CD2F 75DD C8E3 A4DC 2E4F  5173 F30C 38BD 3F2F BE3C

* remotes/vivier2/tags/linux-user-for-6.2-pull-request:
  linux-user/aarch64: Use force_sig_fault()
  linux-user/arm: Use force_sig_fault()
  linux-user: Provide new force_sig_fault() function
  linux-user: Zero out target_siginfo_t in force_sig()
  linux-user/arm: Use force_sig() to deliver fpa11 emulation SIGFPE
  linux-user/arm: Set siginfo_t addr field for SIGTRAP signals
  linux-user/aarch64: Set siginfo_t addr field for SIGTRAP signals

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

4 files changed, 46 insertions, 69 deletions

diff --git a/linux-user/aarch64/cpu_loop.c b/linux-user/aarch64/cpu_loop.c
index 5425b85659..034b737435 100644
--- a/linux-user/aarch64/cpu_loop.c
+++ b/linux-user/aarch64/cpu_loop.c
@@ -79,9 +79,8 @@
 void cpu_loop(CPUARMState *env)
 {
     CPUState *cs = env_cpu(env);
-    int trapnr, ec, fsc;
+    int trapnr, ec, fsc, si_code;
     abi_long ret;
-    target_siginfo_t info;
 
     for (;;) {
         cpu_exec_start(cs);
@@ -110,18 +109,10 @@ void cpu_loop(CPUARMState *env)
             /* just indicate that signals should be handled asap */
             break;
         case EXCP_UDEF:
-            info.si_signo = TARGET_SIGILL;
-            info.si_errno = 0;
-            info.si_code = TARGET_ILL_ILLOPN;
-            info._sifields._sigfault._addr = env->pc;
-            queue_signal(env, info.si_signo, QEMU_SI_FAULT, &info);
+            force_sig_fault(TARGET_SIGILL, TARGET_ILL_ILLOPN, env->pc);
             break;
         case EXCP_PREFETCH_ABORT:
         case EXCP_DATA_ABORT:
-            info.si_signo = TARGET_SIGSEGV;
-            info.si_errno = 0;
-            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);
@@ -130,27 +121,24 @@ void cpu_loop(CPUARMState *env)
             fsc = extract32(env->exception.syndrome, 0, 6);
             switch (fsc) {
             case 0x04 ... 0x07: /* Translation fault, level {0-3} */
-                info.si_code = TARGET_SEGV_MAPERR;
+                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;
+                si_code = TARGET_SEGV_ACCERR;
                 break;
             case 0x11: /* Synchronous Tag Check Fault */
-                info.si_code = TARGET_SEGV_MTESERR;
+                si_code = TARGET_SEGV_MTESERR;
                 break;
             default:
                 g_assert_not_reached();
             }
 
-            queue_signal(env, info.si_signo, QEMU_SI_FAULT, &info);
+            force_sig_fault(TARGET_SIGSEGV, si_code, env->exception.vaddress);
             break;
         case EXCP_DEBUG:
         case EXCP_BKPT:
-            info.si_signo = TARGET_SIGTRAP;
-            info.si_errno = 0;
-            info.si_code = TARGET_TRAP_BRKPT;
-            queue_signal(env, info.si_signo, QEMU_SI_FAULT, &info);
+            force_sig_fault(TARGET_SIGTRAP, TARGET_TRAP_BRKPT, env->pc);
             break;
         case EXCP_SEMIHOST:
             env->xregs[0] = do_common_semihosting(cs);
@@ -170,11 +158,7 @@ void cpu_loop(CPUARMState *env)
         /* Check for MTE asynchronous faults */
         if (unlikely(env->cp15.tfsr_el[0])) {
             env->cp15.tfsr_el[0] = 0;
-            info.si_signo = TARGET_SIGSEGV;
-            info.si_errno = 0;
-            info._sifields._sigfault._addr = 0;
-            info.si_code = TARGET_SEGV_MTEAERR;
-            queue_signal(env, info.si_signo, QEMU_SI_FAULT, &info);
+            force_sig_fault(TARGET_SIGSEGV, TARGET_SEGV_MTEAERR, 0);
         }
 
         process_pending_signals(env);
diff --git a/linux-user/arm/cpu_loop.c b/linux-user/arm/cpu_loop.c
index 07032b3006..ae09adcb95 100644
--- a/linux-user/arm/cpu_loop.c
+++ b/linux-user/arm/cpu_loop.c
@@ -94,7 +94,6 @@ static void arm_kernel_cmpxchg64_helper(CPUARMState *env)
 {
     uint64_t oldval, newval, val;
     uint32_t addr, cpsr;
-    target_siginfo_t info;
 
     /* Based on the 32 bit code in do_kernel_trap */
 
@@ -143,12 +142,9 @@ segv:
     end_exclusive();
     /* We get the PC of the entry address - which is as good as anything,
        on a real kernel what you get depends on which mode it uses. */
-    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;
-    queue_signal(env, info.si_signo, QEMU_SI_FAULT, &info);
+    force_sig_fault(TARGET_SIGSEGV, TARGET_SEGV_MAPERR,
+                    env->exception.vaddress);
 }
 
 /* Handle a jump to the kernel code page.  */
@@ -268,16 +264,13 @@ static bool emulate_arm_fpa11(CPUARMState *env, uint32_t opcode)
     ts->fpa.fpsr |= raise & ~enabled;
 
     if (raise & enabled) {
-        target_siginfo_t info = { };
-
         /*
          * The kernel's nwfpe emulator does not pass a real si_code.
-         * It merely uses send_sig(SIGFPE, current, 1).
+         * It merely uses send_sig(SIGFPE, current, 1), which results in
+         * __send_signal() filling out SI_KERNEL with pid and uid 0 (under
+         * the "SEND_SIG_PRIV" case). That's what our force_sig() does.
          */
-        info.si_signo = TARGET_SIGFPE;
-        info.si_code = TARGET_SI_KERNEL;
-
-        queue_signal(env, info.si_signo, QEMU_SI_FAULT, &info);
+        force_sig(TARGET_SIGFPE);
     } else {
         env->regs[15] += 4;
     }
@@ -289,8 +282,6 @@ void cpu_loop(CPUARMState *env)
     CPUState *cs = env_cpu(env);
     int trapnr;
     unsigned int n, insn;
-    target_siginfo_t info;
-    uint32_t addr;
     abi_ulong ret;
 
     for(;;) {
@@ -325,11 +316,8 @@ void cpu_loop(CPUARMState *env)
                     break;
                 }
 
-                info.si_signo = TARGET_SIGILL;
-                info.si_errno = 0;
-                info.si_code = TARGET_ILL_ILLOPN;
-                info._sifields._sigfault._addr = env->regs[15];
-                queue_signal(env, info.si_signo, QEMU_SI_FAULT, &info);
+                force_sig_fault(TARGET_SIGILL, TARGET_ILL_ILLOPN,
+                                env->regs[15]);
             }
             break;
         case EXCP_SWI:
@@ -397,18 +385,14 @@ void cpu_loop(CPUARMState *env)
                              * Otherwise SIGILL. This includes any SWI with
                              * immediate not originally 0x9fxxxx, because
                              * of the earlier XOR.
+                             * Like the real kernel, we report the addr of the
+                             * SWI in the siginfo si_addr but leave the PC
+                             * pointing at the insn after the SWI.
                              */
-                            info.si_signo = TARGET_SIGILL;
-                            info.si_errno = 0;
-                            info.si_code = TARGET_ILL_ILLTRP;
-                            info._sifields._sigfault._addr = env->regs[15];
-                            if (env->thumb) {
-                                info._sifields._sigfault._addr -= 2;
-                            } else {
-                                info._sifields._sigfault._addr -= 4;
-                            }
-                            queue_signal(env, info.si_signo,
-                                         QEMU_SI_FAULT, &info);
+                            abi_ulong faultaddr = env->regs[15];
+                            faultaddr -= env->thumb ? 2 : 4;
+                            force_sig_fault(TARGET_SIGILL, TARGET_ILL_ILLTRP,
+                                            faultaddr);
                         }
                         break;
                     }
@@ -439,23 +423,14 @@ void cpu_loop(CPUARMState *env)
             break;
         case EXCP_PREFETCH_ABORT:
         case EXCP_DATA_ABORT:
-            addr = env->exception.vaddress;
-            {
-                info.si_signo = TARGET_SIGSEGV;
-                info.si_errno = 0;
-                /* XXX: check env->error_code */
-                info.si_code = TARGET_SEGV_MAPERR;
-                info._sifields._sigfault._addr = addr;
-                queue_signal(env, info.si_signo, QEMU_SI_FAULT, &info);
-            }
+            /* XXX: check env->error_code */
+            force_sig_fault(TARGET_SIGSEGV, TARGET_SEGV_MAPERR,
+                            env->exception.vaddress);
             break;
         case EXCP_DEBUG:
         case EXCP_BKPT:
         excp_debug:
-            info.si_signo = TARGET_SIGTRAP;
-            info.si_errno = 0;
-            info.si_code = TARGET_TRAP_BRKPT;
-            queue_signal(env, info.si_signo, QEMU_SI_FAULT, &info);
+            force_sig_fault(TARGET_SIGTRAP, TARGET_TRAP_BRKPT, env->regs[15]);
             break;
         case EXCP_KERNEL_TRAP:
             if (do_kernel_trap(env))
diff --git a/linux-user/signal-common.h b/linux-user/signal-common.h
index 58ea23f6ea..79511becb4 100644
--- a/linux-user/signal-common.h
+++ b/linux-user/signal-common.h
@@ -40,6 +40,7 @@ void tswap_siginfo(target_siginfo_t *tinfo,
 void set_sigmask(const sigset_t *set);
 void force_sig(int sig);
 void force_sigsegv(int oldsig);
+void force_sig_fault(int sig, int code, abi_ulong addr);
 #if defined(TARGET_ARCH_HAS_SETUP_FRAME)
 void setup_frame(int sig, struct target_sigaction *ka,
                  target_sigset_t *set, CPUArchState *env);
diff --git a/linux-user/signal.c b/linux-user/signal.c
index f8346f5ec5..2038216455 100644
--- a/linux-user/signal.c
+++ b/linux-user/signal.c
@@ -641,7 +641,7 @@ void force_sig(int sig)
 {
     CPUState *cpu = thread_cpu;
     CPUArchState *env = cpu->env_ptr;
-    target_siginfo_t info;
+    target_siginfo_t info = {};
 
     info.si_signo = sig;
     info.si_errno = 0;
@@ -651,6 +651,23 @@ void force_sig(int sig)
     queue_signal(env, info.si_signo, QEMU_SI_KILL, &info);
 }
 
+/*
+ * Force a synchronously taken QEMU_SI_FAULT signal. For QEMU the
+ * 'force' part is handled in process_pending_signals().
+ */
+void force_sig_fault(int sig, int code, abi_ulong addr)
+{
+    CPUState *cpu = thread_cpu;
+    CPUArchState *env = cpu->env_ptr;
+    target_siginfo_t info = {};
+
+    info.si_signo = sig;
+    info.si_errno = 0;
+    info.si_code = code;
+    info._sifields._sigfault._addr = addr;
+    queue_signal(env, sig, QEMU_SI_FAULT, &info);
+}
+
 /* Force a SIGSEGV if we couldn't write to memory trying to set
  * up the signal frame. oldsig is the signal we were trying to handle
  * at the point of failure.