[Qemu-devel] [RFC 11/11] linux-user: Implement signal handling for mipsn32

["Andreas Färber" <afaerber@suse.de>]

Mostly adapted from o32.

Linux no longer seems to have sf_code/rs_code for any of the ABIs.
It's u32 {sf,rt}_pad[2] /* Was: signal trampoline */ now...

Signed-off-by: Andreas Färber <afaerber@suse.de>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Khansa Butt <khansa@kics.edu.pk>
---
 linux-user/signal.c |  104 +++++++++++++++++++++++++++++++++++++++++++++++++--
 1 files changed, 100 insertions(+), 4 deletions(-)

diff --git a/linux-user/signal.c b/linux-user/signal.c
index b33f8cb..82ce4ac 100644
--- a/linux-user/signal.c
+++ b/linux-user/signal.c
@@ -2673,7 +2673,20 @@ long do_rt_sigreturn(CPUState *env)
 
 #elif defined(TARGET_ABI_MIPSN32)
 
-# warning signal handling not implemented
+struct target_ucontext {
+    uint32_t                 tuc_flags;
+    int32_t                  tuc_link;
+    target_stack_t           tuc_stack;
+    struct target_sigcontext tuc_mcontext;
+    target_sigset_t          tuc_sigmask;
+};
+
+struct target_rt_sigframe {
+    uint32_t               rs_ass[4]; /* argument save space for o32 */
+    uint32_t               rs_pad[2]; /* Was: signal trampoline */
+    struct target_siginfo  rs_info;
+    struct target_ucontext rs_uc;
+};
 
 static void setup_frame(int sig, struct target_sigaction *ka,
 			target_sigset_t *set, CPUState *env)
@@ -2685,7 +2698,61 @@ static void setup_rt_frame(int sig, struct target_sigaction *ka,
                            target_siginfo_t *info,
 			   target_sigset_t *set, CPUState *env)
 {
-    fprintf(stderr, "setup_rt_frame: not implemented\n");
+    struct target_rt_sigframe *frame;
+    abi_ulong frame_addr;
+    int i;
+
+    frame_addr = get_sigframe(ka, env, sizeof(*frame));
+    if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 0))
+	goto give_sigsegv;
+
+    //install_sigtramp(frame->rs_pad, TARGET_NR_rt_sigreturn);
+
+    /* Create siginfo. */
+    copy_siginfo_to_user(&frame->rs_info, info);
+
+    /* Create the ucontext. */
+    __put_user(0, &frame->rs_uc.tuc_flags);
+    __put_user(0, &frame->rs_uc.tuc_link);
+    __put_user(target_sigaltstack_used.ss_sp, &frame->rs_uc.tuc_stack.ss_sp);
+    __put_user(target_sigaltstack_used.ss_size, &frame->rs_uc.tuc_stack.ss_size);
+    __put_user(sas_ss_flags(get_sp_from_cpustate(env)),
+               &frame->rs_uc.tuc_stack.ss_flags);
+
+    setup_sigcontext(env, &frame->rs_uc.tuc_mcontext);
+
+    for(i = 0; i < TARGET_NSIG_WORDS; i++) {
+        __put_user(set->sig[i], &frame->rs_uc.tuc_sigmask.sig[i]);
+    }
+
+    /*
+     * Arguments to signal handler:
+     *
+     *   a0 = signal number
+     *   a1 = pointer to struct siginfo
+     *   a2 = pointer to struct ucontext
+     *
+     * $25 and PC point to the signal handler, $29 points to the
+     * struct sigframe.
+     */
+    env->active_tc.gpr[ 4] = sig;
+    env->active_tc.gpr[ 5] = frame_addr
+                             + offsetof(struct target_rt_sigframe, rs_info);
+    env->active_tc.gpr[ 6] = frame_addr
+                             + offsetof(struct target_rt_sigframe, rs_uc);
+    env->active_tc.gpr[29] = frame_addr;
+    //env->active_tc.gpr[31] = frame_addr
+    //                         + offsetof(struct target_rt_sigframe, rs_pad);
+    /* The original kernel code sets CP0_EPC to the handler
+     * since it returns to userland using eret
+     * we cannot do this here, and we must set PC directly */
+    env->active_tc.PC = env->active_tc.gpr[25] = ka->_sa_handler;
+    unlock_user_struct(frame, frame_addr, 1);
+    return;
+
+give_sigsegv:
+    unlock_user_struct(frame, frame_addr, 1);
+    force_sig(TARGET_SIGSEGV/*, current*/);
 }
 
 long do_sigreturn(CPUState *env)
@@ -2696,8 +2763,37 @@ long do_sigreturn(CPUState *env)
 
 long do_rt_sigreturn(CPUState *env)
 {
-    fprintf(stderr, "do_rt_sigreturn: not implemented\n");
-    return -TARGET_ENOSYS;
+    struct target_rt_sigframe *frame;
+    abi_ulong frame_addr;
+    sigset_t blocked;
+
+#if defined(DEBUG_SIGNAL)
+    fprintf(stderr, "do_rt_sigreturn\n");
+#endif
+    frame_addr = env->active_tc.gpr[29];
+    if (!lock_user_struct(VERIFY_READ, frame, frame_addr, 1))
+   	goto badframe;
+
+    target_to_host_sigset(&blocked, &frame->rs_uc.tuc_sigmask);
+    sigprocmask(SIG_SETMASK, &blocked, NULL);
+
+    if (restore_sigcontext(env, &frame->rs_uc.tuc_mcontext))
+        goto badframe;
+
+    if (do_sigaltstack(frame_addr +
+		       offsetof(struct target_rt_sigframe, rs_uc.tuc_stack),
+		       0, get_sp_from_cpustate(env)) == -EFAULT)
+        goto badframe;
+
+    env->active_tc.PC = env->CP0_EPC;
+    /* I am not sure this is right, but it seems to work
+     * maybe a problem with nested signals ? */
+    env->CP0_EPC = 0;
+    return -TARGET_QEMU_ESIGRETURN;
+
+badframe:
+    force_sig(TARGET_SIGSEGV/*, current*/);
+    return 0;
 }
 
 #elif defined(TARGET_ABI_MIPSO32)
-- 
1.7.7