[Qemu-devel] [PATCH v2 11/28] linux-user: Support for restarting system calls for SH4 targets

[Peter Maydell <peter.maydell@linaro.org>]

From: Timothy E Baldwin <T.E.Baldwin99@members.leeds.ac.uk>

Update the SH4 main loop and sigreturn code:
 * on TARGET_ERESTARTSYS, wind guest PC backwards to repeat syscall insn
 * set all guest CPU state within signal.c code on sigreturn
 * handle TARGET_QEMU_ESIGRETURN in the main loop as the indication
   that the main loop should not touch any guest CPU state

Signed-off-by: Timothy Edward Baldwin <T.E.Baldwin99@members.leeds.ac.uk>
Message-id: 1441497448-32489-12-git-send-email-T.E.Baldwin99@members.leeds.ac.uk
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
[PMM: tweak commit message; drop TARGET_USE_ERESTARTSYS define]
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
 linux-user/main.c              |  6 +++++-
 linux-user/sh4/target_signal.h |  1 +
 linux-user/signal.c            | 16 ++++++----------
 3 files changed, 12 insertions(+), 11 deletions(-)

diff --git a/linux-user/main.c b/linux-user/main.c
index eec68c7..c2dc4b2 100644
--- a/linux-user/main.c
+++ b/linux-user/main.c
@@ -2825,7 +2825,11 @@ void cpu_loop(CPUSH4State *env)
                              env->gregs[0],
                              env->gregs[1],
                              0, 0);
-            env->gregs[0] = ret;
+            if (ret == -TARGET_ERESTARTSYS) {
+                env->pc -= 2;
+            } else if (ret != -TARGET_QEMU_ESIGRETURN) {
+                env->gregs[0] = ret;
+            }
             break;
         case EXCP_INTERRUPT:
             /* just indicate that signals should be handled asap */
diff --git a/linux-user/sh4/target_signal.h b/linux-user/sh4/target_signal.h
index e148da0..f9911aa 100644
--- a/linux-user/sh4/target_signal.h
+++ b/linux-user/sh4/target_signal.h
@@ -26,4 +26,5 @@ static inline abi_ulong get_sp_from_cpustate(CPUSH4State *state)
     return state->gregs[15];
 }
 
+
 #endif /* TARGET_SIGNAL_H */
diff --git a/linux-user/signal.c b/linux-user/signal.c
index e742347..8b5ddf2 100644
--- a/linux-user/signal.c
+++ b/linux-user/signal.c
@@ -3202,13 +3202,12 @@ static void setup_sigcontext(struct target_sigcontext *sc,
     __put_user(mask, &sc->oldmask);
 }
 
-static void restore_sigcontext(CPUSH4State *regs, struct target_sigcontext *sc,
-                               target_ulong *r0_p)
+static void restore_sigcontext(CPUSH4State *regs, struct target_sigcontext *sc)
 {
     int i;
 
 #define COPY(x)         __get_user(regs->x, &sc->sc_##x)
-    COPY(gregs[1]);
+    COPY(gregs[0]); COPY(gregs[1]);
     COPY(gregs[2]); COPY(gregs[3]);
     COPY(gregs[4]); COPY(gregs[5]);
     COPY(gregs[6]); COPY(gregs[7]);
@@ -3228,7 +3227,6 @@ static void restore_sigcontext(CPUSH4State *regs, struct target_sigcontext *sc,
     __get_user(regs->fpul, &sc->sc_fpul);
 
     regs->tra = -1;         /* disable syscall checks */
-    __get_user(*r0_p, &sc->sc_gregs[0]);
 }
 
 static void setup_frame(int sig, struct target_sigaction *ka,
@@ -3345,7 +3343,6 @@ long do_sigreturn(CPUSH4State *regs)
     abi_ulong frame_addr;
     sigset_t blocked;
     target_sigset_t target_set;
-    target_ulong r0;
     int i;
     int err = 0;
 
@@ -3366,10 +3363,10 @@ long do_sigreturn(CPUSH4State *regs)
     target_to_host_sigset_internal(&blocked, &target_set);
     do_sigprocmask(SIG_SETMASK, &blocked, NULL);
 
-    restore_sigcontext(regs, &frame->sc, &r0);
+    restore_sigcontext(regs, &frame->sc);
 
     unlock_user_struct(frame, frame_addr, 0);
-    return r0;
+    return -TARGET_QEMU_ESIGRETURN;
 
 badframe:
     unlock_user_struct(frame, frame_addr, 0);
@@ -3382,7 +3379,6 @@ long do_rt_sigreturn(CPUSH4State *regs)
     struct target_rt_sigframe *frame;
     abi_ulong frame_addr;
     sigset_t blocked;
-    target_ulong r0;
 
     frame_addr = regs->gregs[15];
     trace_user_do_rt_sigreturn(regs, frame_addr);
@@ -3393,7 +3389,7 @@ long do_rt_sigreturn(CPUSH4State *regs)
     target_to_host_sigset(&blocked, &frame->uc.tuc_sigmask);
     do_sigprocmask(SIG_SETMASK, &blocked, NULL);
 
-    restore_sigcontext(regs, &frame->uc.tuc_mcontext, &r0);
+    restore_sigcontext(regs, &frame->uc.tuc_mcontext);
 
     if (do_sigaltstack(frame_addr +
                        offsetof(struct target_rt_sigframe, uc.tuc_stack),
@@ -3402,7 +3398,7 @@ long do_rt_sigreturn(CPUSH4State *regs)
     }
 
     unlock_user_struct(frame, frame_addr, 0);
-    return r0;
+    return -TARGET_QEMU_ESIGRETURN;
 
 badframe:
     unlock_user_struct(frame, frame_addr, 0);
-- 
1.9.1