s390: switch to generic sigaltstack

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

7 files changed, 7 insertions, 83 deletions

diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index b5ea38c25647..117f3151cc13 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -140,6 +140,7 @@ config S390
         select HAVE_MOD_ARCH_SPECIFIC
         select MODULES_USE_ELF_RELA
         select CLONE_BACKWARDS2
+        select GENERIC_SIGALTSTACK
 
 config SCHED_OMIT_FRAME_POINTER
         def_bool y
diff --git a/arch/s390/kernel/compat_linux.h b/arch/s390/kernel/compat_linux.h
index d4d0239970ac..e2b2a51cf49b 100644
--- a/arch/s390/kernel/compat_linux.h
+++ b/arch/s390/kernel/compat_linux.h
@@ -75,17 +75,11 @@ struct sigaction32 {
         compat_sigset_t sa_mask;        /* mask last for extensibility */
 };
 
-typedef struct {
-        __u32                   ss_sp;          /* pointer */
-        int                     ss_flags;
-        compat_size_t           ss_size;
-} stack_t32;
-
 /* asm/ucontext.h */
 struct ucontext32 {
         __u32                   uc_flags;
         __u32                   uc_link;        /* pointer */   
-        stack_t32               uc_stack;
+        compat_stack_t          uc_stack;
         _sigregs32              uc_mcontext;
         compat_sigset_t         uc_sigmask;     /* mask last for extensibility */
 };
@@ -153,5 +147,4 @@ long sys32_sigaction(int sig, const struct old_sigaction32 __user *act,
                      struct old_sigaction32 __user *oact);
 long sys32_rt_sigaction(int sig, const struct sigaction32 __user *act,
                         struct sigaction32 __user *oact, size_t sigsetsize);
-long sys32_sigaltstack(const stack_t32 __user *uss, stack_t32 __user *uoss);
 #endif /* _ASM_S390X_S390_H */
diff --git a/arch/s390/kernel/compat_signal.c b/arch/s390/kernel/compat_signal.c
index 593fcc9253fc..eacb0d6058a3 100644
--- a/arch/s390/kernel/compat_signal.c
+++ b/arch/s390/kernel/compat_signal.c
@@ -234,45 +234,6 @@ sys32_rt_sigaction(int sig, const struct sigaction32 __user *act,
         return ret;
 }
 
-asmlinkage long
-sys32_sigaltstack(const stack_t32 __user *uss, stack_t32 __user *uoss)
-{
-        struct pt_regs *regs = task_pt_regs(current);
-        stack_t kss, koss;
-        unsigned long ss_sp;
-        int ret, err = 0;
-        mm_segment_t old_fs = get_fs();
-
-        if (uss) {
-                if (!access_ok(VERIFY_READ, uss, sizeof(*uss)))
-                        return -EFAULT;
-                err |= __get_user(ss_sp, &uss->ss_sp);
-                err |= __get_user(kss.ss_size, &uss->ss_size);
-                err |= __get_user(kss.ss_flags, &uss->ss_flags);
-                if (err)
-                        return -EFAULT;
-                kss.ss_sp = (void __user *) ss_sp;
-        }
-
-        set_fs (KERNEL_DS);
-        ret = do_sigaltstack((stack_t __force __user *) (uss ? &kss : NULL),
-                             (stack_t __force __user *) (uoss ? &koss : NULL),
-                             regs->gprs[15]);
-        set_fs (old_fs);
-
-        if (!ret && uoss) {
-                if (!access_ok(VERIFY_WRITE, uoss, sizeof(*uoss)))
-                        return -EFAULT;
-                ss_sp = (unsigned long) koss.ss_sp;
-                err |= __put_user(ss_sp, &uoss->ss_sp);
-                err |= __put_user(koss.ss_size, &uoss->ss_size);
-                err |= __put_user(koss.ss_flags, &uoss->ss_flags);
-                if (err)
-                        return -EFAULT;
-        }
-        return ret;
-}
-
 static int save_sigregs32(struct pt_regs *regs, _sigregs32 __user *sregs)
 {
         _s390_regs_common32 regs32;
@@ -380,10 +341,6 @@ asmlinkage long sys32_rt_sigreturn(void)
         struct pt_regs *regs = task_pt_regs(current);
         rt_sigframe32 __user *frame = (rt_sigframe32 __user *)regs->gprs[15];
         sigset_t set;
-        stack_t st;
-        __u32 ss_sp;
-        int err;
-        mm_segment_t old_fs = get_fs();
 
         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
                 goto badframe;
@@ -394,15 +351,8 @@ asmlinkage long sys32_rt_sigreturn(void)
                 goto badframe;
         if (restore_sigregs_gprs_high(regs, frame->gprs_high))
                 goto badframe;
-        err = __get_user(ss_sp, &frame->uc.uc_stack.ss_sp);
-        st.ss_sp = compat_ptr(ss_sp);
-        err |= __get_user(st.ss_size, &frame->uc.uc_stack.ss_size);
-        err |= __get_user(st.ss_flags, &frame->uc.uc_stack.ss_flags);
-        if (err)
+        if (compat_restore_altstack(&frame->uc.uc_stack))
                 goto badframe; 
-        set_fs (KERNEL_DS);
-        do_sigaltstack((stack_t __force __user *)&st, NULL, regs->gprs[15]);
-        set_fs (old_fs);
         return regs->gprs[2];
 badframe:
         force_sig(SIGSEGV, current);
@@ -530,10 +480,7 @@ static int setup_rt_frame32(int sig, struct k_sigaction *ka, siginfo_t *info,
         /* Create the ucontext.  */
         err |= __put_user(UC_EXTENDED, &frame->uc.uc_flags);
         err |= __put_user(0, &frame->uc.uc_link);
-        err |= __put_user(current->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
-        err |= __put_user(sas_ss_flags(regs->gprs[15]),
-                          &frame->uc.uc_stack.ss_flags);
-        err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
+        err |= __compat_save_altstack(&frame->uc.uc_stack, regs->gprs[15]);
         err |= save_sigregs32(regs, &frame->uc.uc_mcontext);
         err |= save_sigregs_gprs_high(regs, frame->gprs_high);
         err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
diff --git a/arch/s390/kernel/compat_wrapper.S b/arch/s390/kernel/compat_wrapper.S
index 9b9a805656b5..3c3b9c8b90c1 100644
--- a/arch/s390/kernel/compat_wrapper.S
+++ b/arch/s390/kernel/compat_wrapper.S
@@ -760,11 +760,6 @@ ENTRY(sys32_capset_wrapper)
         llgtr   %r3,%r3                 # const cap_user_data_t
         jg      sys_capset              # branch to system call
 
-ENTRY(sys32_sigaltstack_wrapper)
-        llgtr   %r2,%r2                 # const stack_emu31_t *
-        llgtr   %r3,%r3                 # stack_emu31_t *
-        jg      sys32_sigaltstack
-
 ENTRY(sys32_sendfile_wrapper)
         lgfr    %r2,%r2                 # int
         lgfr    %r3,%r3                 # int
diff --git a/arch/s390/kernel/entry.h b/arch/s390/kernel/entry.h
index 2711936fe706..d56319aa1d56 100644
--- a/arch/s390/kernel/entry.h
+++ b/arch/s390/kernel/entry.h
@@ -76,7 +76,6 @@ long sys_s390_fallocate(int fd, int mode, loff_t offset, u32 len_high,
 long sys_sigsuspend(int history0, int history1, old_sigset_t mask);
 long sys_sigaction(int sig, const struct old_sigaction __user *act,
                    struct old_sigaction __user *oact);
-long sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss);
 long sys_sigreturn(void);
 long sys_rt_sigreturn(void);
 long sys32_sigreturn(void);
diff --git a/arch/s390/kernel/signal.c b/arch/s390/kernel/signal.c
index c3ff70a7b247..fda41480b0bd 100644
--- a/arch/s390/kernel/signal.c
+++ b/arch/s390/kernel/signal.c
@@ -89,13 +89,6 @@ SYSCALL_DEFINE3(sigaction, int, sig, const struct old_sigaction __user *, act,
         return ret;
 }
 
-SYSCALL_DEFINE2(sigaltstack, const stack_t __user *, uss,
-                stack_t __user *, uoss)
-{
-        struct pt_regs *regs = task_pt_regs(current);
-        return do_sigaltstack(uss, uoss, regs->gprs[15]);
-}
-
 /* Returns non-zero on fault. */
 static int save_sigregs(struct pt_regs *regs, _sigregs __user *sregs)
 {
@@ -190,8 +183,7 @@ SYSCALL_DEFINE0(rt_sigreturn)
         set_current_blocked(&set);
         if (restore_sigregs(regs, &frame->uc.uc_mcontext))
                 goto badframe;
-        if (do_sigaltstack(&frame->uc.uc_stack, NULL,
-                           regs->gprs[15]) == -EFAULT)
+        if (restore_altstack(&frame->uc.uc_stack))
                 goto badframe;
         return regs->gprs[2];
 badframe:
@@ -325,10 +317,7 @@ static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
         /* Create the ucontext.  */
         err |= __put_user(0, &frame->uc.uc_flags);
         err |= __put_user(NULL, &frame->uc.uc_link);
-        err |= __put_user((void __user *)current->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
-        err |= __put_user(sas_ss_flags(regs->gprs[15]),
-                          &frame->uc.uc_stack.ss_flags);
-        err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
+        err |= __save_altstack(&frame->uc.uc_stack, regs->gprs[15]);
         err |= save_sigregs(regs, &frame->uc.uc_mcontext);
         err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
         if (err)
diff --git a/arch/s390/kernel/syscalls.S b/arch/s390/kernel/syscalls.S
index 6a6c61f94dd3..65547cb9ac7b 100644
--- a/arch/s390/kernel/syscalls.S
+++ b/arch/s390/kernel/syscalls.S
@@ -194,7 +194,7 @@ SYSCALL(sys_chown16,sys_ni_syscall,sys32_chown16_wrapper)	/* old chown16 syscall
 SYSCALL(sys_getcwd,sys_getcwd,sys32_getcwd_wrapper)
 SYSCALL(sys_capget,sys_capget,sys32_capget_wrapper)
 SYSCALL(sys_capset,sys_capset,sys32_capset_wrapper)             /* 185 */
-SYSCALL(sys_sigaltstack,sys_sigaltstack,sys32_sigaltstack_wrapper)
+SYSCALL(sys_sigaltstack,sys_sigaltstack,compat_sys_sigaltstack)
 SYSCALL(sys_sendfile,sys_sendfile64,sys32_sendfile_wrapper)
 NI_SYSCALL                                                      /* streams1 */
 NI_SYSCALL                                                      /* streams2 */