linux-user/microblaze: Implement rt signal frames

Allows microblaze to pass tests/tcg/multiarch/linux-test.c.

Tested-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
Reviewed-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

linux-user/microblaze/signal.c

@@ -35,9 +35,9 @@ struct target_stack_t {
 struct target_ucontext {
     abi_ulong tuc_flags;
     abi_ulong tuc_link;
-    struct target_stack_t tuc_stack;
+    target_stack_t tuc_stack;
     struct target_sigcontext tuc_mcontext;
-    uint32_t tuc_extramask[TARGET_NSIG_WORDS - 1];
+    target_sigset_t tuc_sigmask;
 };
 
 /* Signal frames. */
@@ -47,9 +47,9 @@ struct target_signal_frame {
     uint32_t tramp[2];
 };
 
-struct rt_signal_frame {
-    siginfo_t info;
-    ucontext_t uc;
+struct target_rt_sigframe {
+    target_siginfo_t info;
+    struct target_ucontext uc;
     uint32_t tramp[2];
 };
 
@@ -200,7 +200,55 @@ void setup_rt_frame(int sig, struct target_sigaction *ka,
                     target_siginfo_t *info,
                     target_sigset_t *set, CPUMBState *env)
 {
-    qemu_log_mask(LOG_UNIMP, "setup_rt_frame: not implemented\n");
+    struct target_rt_sigframe *frame;
+    abi_ulong frame_addr;
+
+    frame_addr = get_sigframe(ka, env, sizeof *frame);
+    trace_user_setup_rt_frame(env, frame_addr);
+
+    if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 0)) {
+        force_sigsegv(sig);
+        return;
+    }
+
+    tswap_siginfo(&frame->info, info);
+
+    __put_user(0, &frame->uc.tuc_flags);
+    __put_user(0, &frame->uc.tuc_link);
+
+    target_save_altstack(&frame->uc.tuc_stack, env);
+    setup_sigcontext(&frame->uc.tuc_mcontext, env);
+
+    for (int i = 0; i < TARGET_NSIG_WORDS; i++) {
+        __put_user(set->sig[i], &frame->uc.tuc_sigmask.sig[i]);
+    }
+
+    /* Kernel does not use SA_RESTORER. */
+
+    /* addi r12, r0, __NR_sigreturn */
+    __put_user(0x31800000U | TARGET_NR_rt_sigreturn, frame->tramp + 0);
+    /* brki r14, 0x8 */
+    __put_user(0xb9cc0008U, frame->tramp + 1);
+
+    /*
+     * Return from sighandler will jump to the tramp.
+     * Negative 8 offset because return is rtsd r15, 8
+     */
+    env->regs[15] =
+        frame_addr + offsetof(struct target_rt_sigframe, tramp) - 8;
+
+    /* Set up registers for signal handler */
+    env->regs[1] = frame_addr;
+
+    /* Signal handler args: */
+    env->regs[5] = sig;
+    env->regs[6] = frame_addr + offsetof(struct target_rt_sigframe, info);
+    env->regs[7] = frame_addr + offsetof(struct target_rt_sigframe, uc);
+
+    /* Offset to handle microblaze rtid r14, 0 */
+    env->pc = (unsigned long)ka->_sa_handler;
+
+    unlock_user_struct(frame, frame_addr, 1);
 }
 
 long do_sigreturn(CPUMBState *env)
@@ -239,7 +287,32 @@ badframe:
 
 long do_rt_sigreturn(CPUMBState *env)
 {
-    trace_user_do_rt_sigreturn(env, 0);
-    qemu_log_mask(LOG_UNIMP, "do_rt_sigreturn: not implemented\n");
-    return -TARGET_ENOSYS;
+    struct target_rt_sigframe *frame = NULL;
+    abi_ulong frame_addr = env->regs[1];
+    sigset_t set;
+
+    trace_user_do_rt_sigreturn(env, frame_addr);
+
+    if  (!lock_user_struct(VERIFY_READ, frame, frame_addr, 1)) {
+        goto badframe;
+    }
+
+    target_to_host_sigset(&set, &frame->uc.tuc_sigmask);
+    set_sigmask(&set);
+
+    restore_sigcontext(&frame->uc.tuc_mcontext, env);
+
+    if (do_sigaltstack(frame_addr +
+                       offsetof(struct target_rt_sigframe, uc.tuc_stack),
+                       0, get_sp_from_cpustate(env)) == -EFAULT) {
+        goto badframe;
+    }
+
+    unlock_user_struct(frame, frame_addr, 0);
+    return -TARGET_QEMU_ESIGRETURN;
+
+ badframe:
+    unlock_user_struct(frame, frame_addr, 0);
+    force_sig(TARGET_SIGSEGV);
+    return -TARGET_QEMU_ESIGRETURN;
 }