linux-user: Use target_restore_altstack in all sigreturn

Note that target_restore_altstack uses the host memory
pointer that we have already verified, so TARGET_EFAULT
is not a possible return value.

Note that using -EFAULT was a bug.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20210426025334.1168495-3-richard.henderson@linaro.org>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>

16 files changed, 18 insertions, 81 deletions

diff --git a/linux-user/aarch64/signal.c b/linux-user/aarch64/signal.c
index b591790c22..2a1b7dbcdc 100644
--- a/linux-user/aarch64/signal.c
+++ b/linux-user/aarch64/signal.c
@@ -561,11 +561,7 @@ long do_rt_sigreturn(CPUARMState *env)
         goto badframe;
     }
 
-    if (do_sigaltstack(frame_addr +
-            offsetof(struct target_rt_sigframe, uc.tuc_stack),
-            0, get_sp_from_cpustate(env)) == -EFAULT) {
-        goto badframe;
-    }
+    target_restore_altstack(&frame->uc.tuc_stack, get_sp_from_cpustate(env));
 
     unlock_user_struct(frame, frame_addr, 0);
     return -TARGET_QEMU_ESIGRETURN;
diff --git a/linux-user/alpha/signal.c b/linux-user/alpha/signal.c
index c5c27ce084..0af0227118 100644
--- a/linux-user/alpha/signal.c
+++ b/linux-user/alpha/signal.c
@@ -257,11 +257,7 @@ long do_rt_sigreturn(CPUAlphaState *env)
     set_sigmask(&set);
 
     restore_sigcontext(env, &frame->uc.tuc_mcontext);
-    if (do_sigaltstack(frame_addr + offsetof(struct target_rt_sigframe,
-                                             uc.tuc_stack),
-                       0, env->ir[IR_SP]) == -EFAULT) {
-        goto badframe;
-    }
+    target_restore_altstack(&frame->uc.tuc_stack, env->ir[IR_SP]);
 
     unlock_user_struct(frame, frame_addr, 0);
     return -TARGET_QEMU_ESIGRETURN;
diff --git a/linux-user/arm/signal.c b/linux-user/arm/signal.c
index f21d1535e4..b7a772302f 100644
--- a/linux-user/arm/signal.c
+++ b/linux-user/arm/signal.c
@@ -685,11 +685,7 @@ static int do_sigframe_return_v2(CPUARMState *env,
         }
     }
 
-    if (do_sigaltstack(context_addr
-                       + offsetof(struct target_ucontext_v2, tuc_stack),
-                       0, get_sp_from_cpustate(env)) == -EFAULT) {
-        return 1;
-    }
+    target_restore_altstack(&uc->tuc_stack, get_sp_from_cpustate(env));
 
 #if 0
     /* Send SIGTRAP if we're single-stepping */
@@ -773,8 +769,7 @@ static long do_rt_sigreturn_v1(CPUARMState *env)
         goto badframe;
     }
 
-    if (do_sigaltstack(frame_addr + offsetof(struct rt_sigframe_v1, uc.tuc_stack), 0, get_sp_from_cpustate(env)) == -EFAULT)
-        goto badframe;
+    target_restore_altstack(&frame->uc.tuc_stack, get_sp_from_cpustate(env));
 
 #if 0
     /* Send SIGTRAP if we're single-stepping */
diff --git a/linux-user/hexagon/signal.c b/linux-user/hexagon/signal.c
index fde8dc93b7..3854eb4709 100644
--- a/linux-user/hexagon/signal.c
+++ b/linux-user/hexagon/signal.c
@@ -260,11 +260,7 @@ long do_rt_sigreturn(CPUHexagonState *env)
     }
 
     restore_ucontext(env, &frame->uc);
-
-    if (do_sigaltstack(frame_addr + offsetof(struct target_rt_sigframe,
-            uc.uc_stack), 0, get_sp_from_cpustate(env)) == -EFAULT) {
-        goto badframe;
-    }
+    target_restore_altstack(&frame->uc.uc_stack, get_sp_from_cpustate(env));
 
     unlock_user_struct(frame, frame_addr, 0);
     return -TARGET_QEMU_ESIGRETURN;
diff --git a/linux-user/hppa/signal.c b/linux-user/hppa/signal.c
index d1a58feeb3..578874cf27 100644
--- a/linux-user/hppa/signal.c
+++ b/linux-user/hppa/signal.c
@@ -187,13 +187,7 @@ long do_rt_sigreturn(CPUArchState *env)
     set_sigmask(&set);
 
     restore_sigcontext(env, &frame->uc.tuc_mcontext);
-    unlock_user_struct(frame, frame_addr, 0);
-
-    if (do_sigaltstack(frame_addr + offsetof(struct target_rt_sigframe,
-                                             uc.tuc_stack),
-                       0, env->gr[30]) == -EFAULT) {
-        goto badframe;
-    }
+    target_restore_altstack(&frame->uc.tuc_stack, env->gr[30]);
 
     unlock_user_struct(frame, frame_addr, 0);
     return -TARGET_QEMU_ESIGRETURN;
diff --git a/linux-user/i386/signal.c b/linux-user/i386/signal.c
index 9320e1d472..3a0a1546a6 100644
--- a/linux-user/i386/signal.c
+++ b/linux-user/i386/signal.c
@@ -581,10 +581,7 @@ long do_rt_sigreturn(CPUX86State *env)
         goto badframe;
     }
 
-    if (do_sigaltstack(frame_addr + offsetof(struct rt_sigframe, uc.tuc_stack), 0,
-                       get_sp_from_cpustate(env)) == -EFAULT) {
-        goto badframe;
-    }
+    target_restore_altstack(&frame->uc.tuc_stack, get_sp_from_cpustate(env));
 
     unlock_user_struct(frame, frame_addr, 0);
     return -TARGET_QEMU_ESIGRETURN;
diff --git a/linux-user/m68k/signal.c b/linux-user/m68k/signal.c
index 49ff87c77b..004b59fb61 100644
--- a/linux-user/m68k/signal.c
+++ b/linux-user/m68k/signal.c
@@ -400,10 +400,7 @@ long do_rt_sigreturn(CPUM68KState *env)
     if (target_rt_restore_ucontext(env, &frame->uc))
         goto badframe;
 
-    if (do_sigaltstack(frame_addr +
-                       offsetof(struct target_rt_sigframe, uc.tuc_stack),
-                       0, get_sp_from_cpustate(env)) == -EFAULT)
-        goto badframe;
+    target_restore_altstack(&frame->uc.tuc_stack, get_sp_from_cpustate(env));
 
     unlock_user_struct(frame, frame_addr, 0);
     return -TARGET_QEMU_ESIGRETURN;
diff --git a/linux-user/microblaze/signal.c b/linux-user/microblaze/signal.c
index cf0707b556..f59a1faf47 100644
--- a/linux-user/microblaze/signal.c
+++ b/linux-user/microblaze/signal.c
@@ -209,11 +209,7 @@ long do_rt_sigreturn(CPUMBState *env)
 
     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;
-    }
+    target_restore_altstack(&frame->uc.tuc_stack, get_sp_from_cpustate(env));
 
     unlock_user_struct(frame, frame_addr, 0);
     return -TARGET_QEMU_ESIGRETURN;
diff --git a/linux-user/mips/signal.c b/linux-user/mips/signal.c
index 455a8a229a..456fa64f41 100644
--- a/linux-user/mips/signal.c
+++ b/linux-user/mips/signal.c
@@ -368,11 +368,7 @@ long do_rt_sigreturn(CPUMIPSState *env)
     set_sigmask(&blocked);
 
     restore_sigcontext(env, &frame->rs_uc.tuc_mcontext);
-
-    if (do_sigaltstack(frame_addr +
-                       offsetof(struct target_rt_sigframe, rs_uc.tuc_stack),
-                       0, get_sp_from_cpustate(env)) == -EFAULT)
-        goto badframe;
+    target_restore_altstack(&frame->rs_uc.tuc_stack, get_sp_from_cpustate(env));
 
     env->active_tc.PC = env->CP0_EPC;
     mips_set_hflags_isa_mode_from_pc(env);
diff --git a/linux-user/nios2/signal.c b/linux-user/nios2/signal.c
index 7d535065ed..751ea88811 100644
--- a/linux-user/nios2/signal.c
+++ b/linux-user/nios2/signal.c
@@ -82,9 +82,7 @@ static int rt_restore_ucontext(CPUNios2State *env, struct target_ucontext *uc,
                                int *pr2)
 {
     int temp;
-    abi_ulong off, frame_addr = env->regs[R_SP];
     unsigned long *gregs = uc->tuc_mcontext.gregs;
-    int err;
 
     /* Always make any pending restarted system calls return -EINTR */
     /* current->restart_block.fn = do_no_restart_syscall; */
@@ -130,11 +128,7 @@ static int rt_restore_ucontext(CPUNios2State *env, struct target_ucontext *uc,
     __get_user(env->regs[R_RA], &gregs[23]);
     __get_user(env->regs[R_SP], &gregs[28]);
 
-    off = offsetof(struct target_rt_sigframe, uc.tuc_stack);
-    err = do_sigaltstack(frame_addr + off, 0, get_sp_from_cpustate(env));
-    if (err == -EFAULT) {
-        return 1;
-    }
+    target_restore_altstack(&uc->tuc_stack, get_sp_from_cpustate(env));
 
     *pr2 = env->regs[2];
     return 0;
diff --git a/linux-user/openrisc/signal.c b/linux-user/openrisc/signal.c
index 232ad82b98..86f94d7f76 100644
--- a/linux-user/openrisc/signal.c
+++ b/linux-user/openrisc/signal.c
@@ -158,10 +158,7 @@ long do_rt_sigreturn(CPUOpenRISCState *env)
     set_sigmask(&set);
 
     restore_sigcontext(env, &frame->uc.tuc_mcontext);
-    if (do_sigaltstack(frame_addr + offsetof(target_rt_sigframe, uc.tuc_stack),
-                       0, frame_addr) == -EFAULT) {
-        goto badframe;
-    }
+    target_restore_altstack(&frame->uc.tuc_stack, frame_addr);
 
     unlock_user_struct(frame, frame_addr, 0);
     return cpu_get_gpr(env, 11);
diff --git a/linux-user/ppc/signal.c b/linux-user/ppc/signal.c
index bad38f8ed9..b44d5ce73c 100644
--- a/linux-user/ppc/signal.c
+++ b/linux-user/ppc/signal.c
@@ -655,9 +655,7 @@ long do_rt_sigreturn(CPUPPCState *env)
     if (do_setcontext(&rt_sf->uc, env, 1))
         goto sigsegv;
 
-    do_sigaltstack(rt_sf_addr
-                   + offsetof(struct target_rt_sigframe, uc.tuc_stack),
-                   0, env->gpr[1]);
+    target_restore_altstack(&rt_sf->uc.tuc_stack, env->gpr[1]);
 
     unlock_user_struct(rt_sf, rt_sf_addr, 1);
     return -TARGET_QEMU_ESIGRETURN;
diff --git a/linux-user/riscv/signal.c b/linux-user/riscv/signal.c
index 67a95dbc7b..81d1129da3 100644
--- a/linux-user/riscv/signal.c
+++ b/linux-user/riscv/signal.c
@@ -192,11 +192,7 @@ long do_rt_sigreturn(CPURISCVState *env)
     }
 
     restore_ucontext(env, &frame->uc);
-
-    if (do_sigaltstack(frame_addr + offsetof(struct target_rt_sigframe,
-            uc.uc_stack), 0, get_sp_from_cpustate(env)) == -EFAULT) {
-        goto badframe;
-    }
+    target_restore_altstack(&frame->uc.uc_stack, get_sp_from_cpustate(env));
 
     unlock_user_struct(frame, frame_addr, 0);
     return -TARGET_QEMU_ESIGRETURN;
diff --git a/linux-user/s390x/signal.c b/linux-user/s390x/signal.c
index 7107c5fb53..73806f5472 100644
--- a/linux-user/s390x/signal.c
+++ b/linux-user/s390x/signal.c
@@ -307,10 +307,8 @@ long do_rt_sigreturn(CPUS390XState *env)
         goto badframe;
     }
 
-    if (do_sigaltstack(frame_addr + offsetof(rt_sigframe, uc.tuc_stack), 0,
-                       get_sp_from_cpustate(env)) == -EFAULT) {
-        goto badframe;
-    }
+    target_restore_altstack(&frame->uc.tuc_stack, get_sp_from_cpustate(env));
+
     unlock_user_struct(frame, frame_addr, 0);
     return -TARGET_QEMU_ESIGRETURN;
 
diff --git a/linux-user/sh4/signal.c b/linux-user/sh4/signal.c
index 29c1ee30e6..684f18da58 100644
--- a/linux-user/sh4/signal.c
+++ b/linux-user/sh4/signal.c
@@ -323,12 +323,7 @@ long do_rt_sigreturn(CPUSH4State *regs)
     set_sigmask(&blocked);
 
     restore_sigcontext(regs, &frame->uc.tuc_mcontext);
-
-    if (do_sigaltstack(frame_addr +
-                       offsetof(struct target_rt_sigframe, uc.tuc_stack),
-                       0, get_sp_from_cpustate(regs)) == -EFAULT) {
-        goto badframe;
-    }
+    target_restore_altstack(&frame->uc.tuc_stack, get_sp_from_cpustate(regs));
 
     unlock_user_struct(frame, frame_addr, 0);
     return -TARGET_QEMU_ESIGRETURN;
diff --git a/linux-user/xtensa/signal.c b/linux-user/xtensa/signal.c
index 590f0313ff..22ec6cdeb9 100644
--- a/linux-user/xtensa/signal.c
+++ b/linux-user/xtensa/signal.c
@@ -253,12 +253,8 @@ long do_rt_sigreturn(CPUXtensaState *env)
     set_sigmask(&set);
 
     restore_sigcontext(env, frame);
+    target_restore_altstack(&frame->uc.tuc_stack, get_sp_from_cpustate(env));
 
-    if (do_sigaltstack(frame_addr +
-                       offsetof(struct target_rt_sigframe, uc.tuc_stack),
-                       0, get_sp_from_cpustate(env)) == -TARGET_EFAULT) {
-        goto badframe;
-    }
     unlock_user_struct(frame, frame_addr, 0);
     return -TARGET_QEMU_ESIGRETURN;