Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal

Pull signal handling cleanups from Al Viro:
 "sigaltstack infrastructure + conversion for x86, alpha and um,
  COMPAT_SYSCALL_DEFINE infrastructure.

  Note that there are several conflicts between "unify
  SS_ONSTACK/SS_DISABLE definitions" and UAPI patches in mainline;
  resolution is trivial - just remove definitions of SS_ONSTACK and
  SS_DISABLED from arch/*/uapi/asm/signal.h; they are all identical and
  include/uapi/linux/signal.h contains the unified variant."

Fixed up conflicts as per Al.

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal:
  alpha: switch to generic sigaltstack
  new helpers: __save_altstack/__compat_save_altstack, switch x86 and um to those
  generic compat_sys_sigaltstack()
  introduce generic sys_sigaltstack(), switch x86 and um to it
  new helper: compat_user_stack_pointer()
  new helper: restore_altstack()
  unify SS_ONSTACK/SS_DISABLE definitions
  new helper: current_user_stack_pointer()
  missing user_stack_pointer() instances
  Bury the conditionals from kernel_thread/kernel_execve series
  COMPAT_SYSCALL_DEFINE: infrastructure

5 files changed, 3 insertions, 18 deletions

diff --git a/arch/alpha/Kconfig b/arch/alpha/Kconfig
index 5dd7f5db24d4..9d5904cc7712 100644
--- a/arch/alpha/Kconfig
+++ b/arch/alpha/Kconfig
@@ -20,10 +20,9 @@ config ALPHA
         select GENERIC_CMOS_UPDATE
         select GENERIC_STRNCPY_FROM_USER
         select GENERIC_STRNLEN_USER
-        select GENERIC_KERNEL_THREAD
-        select GENERIC_KERNEL_EXECVE
         select HAVE_MOD_ARCH_SPECIFIC
         select MODULES_USE_ELF_RELA
+        select GENERIC_SIGALTSTACK
         help
           The Alpha is a 64-bit general-purpose processor designed and
           marketed by the Digital Equipment Corporation of blessed memory,
diff --git a/arch/alpha/include/asm/ptrace.h b/arch/alpha/include/asm/ptrace.h
index df9a6cd748d5..21128505ddbe 100644
--- a/arch/alpha/include/asm/ptrace.h
+++ b/arch/alpha/include/asm/ptrace.h
@@ -8,6 +8,7 @@
 #define user_mode(regs) (((regs)->ps & 8) != 0)
 #define instruction_pointer(regs) ((regs)->pc)
 #define profile_pc(regs) instruction_pointer(regs)
+#define current_user_stack_pointer() rdusp()
 
 #define task_pt_regs(task) \
   ((struct pt_regs *) (task_stack_page(task) + 2*PAGE_SIZE) - 1)
diff --git a/arch/alpha/include/asm/unistd.h b/arch/alpha/include/asm/unistd.h
index d6069ff3b1c8..b3396ee039b7 100644
--- a/arch/alpha/include/asm/unistd.h
+++ b/arch/alpha/include/asm/unistd.h
@@ -15,7 +15,6 @@
 #define __ARCH_WANT_SYS_OLDUMOUNT
 #define __ARCH_WANT_SYS_SIGPENDING
 #define __ARCH_WANT_SYS_RT_SIGSUSPEND
-#define __ARCH_WANT_SYS_EXECVE
 #define __ARCH_WANT_SYS_FORK
 #define __ARCH_WANT_SYS_VFORK
 #define __ARCH_WANT_SYS_CLONE
diff --git a/arch/alpha/include/uapi/asm/signal.h b/arch/alpha/include/uapi/asm/signal.h
index 965bbfa59c65..dd4ca4bcbb4a 100644
--- a/arch/alpha/include/uapi/asm/signal.h
+++ b/arch/alpha/include/uapi/asm/signal.h
@@ -84,12 +84,6 @@ typedef unsigned long sigset_t;
 #define SA_ONESHOT      SA_RESETHAND
 #define SA_NOMASK       SA_NODEFER
 
-/* 
- * sigaltstack controls
- */
-#define SS_ONSTACK      1
-#define SS_DISABLE      2
-
 #define MINSIGSTKSZ     4096
 #define SIGSTKSZ        16384
 
diff --git a/arch/alpha/kernel/signal.c b/arch/alpha/kernel/signal.c
index 336393c9c11f..02d02c047f17 100644
--- a/arch/alpha/kernel/signal.c
+++ b/arch/alpha/kernel/signal.c
@@ -122,12 +122,6 @@ SYSCALL_DEFINE1(sigsuspend, old_sigset_t, mask)
         return sigsuspend(&blocked);
 }
 
-asmlinkage int
-sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss)
-{
-        return do_sigaltstack(uss, uoss, rdusp());
-}
-
 /*
  * Do a signal return; undo the signal stack.
  */
@@ -418,9 +412,7 @@ setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
         err |= __put_user(0, &frame->uc.uc_flags);
         err |= __put_user(0, &frame->uc.uc_link);
         err |= __put_user(set->sig[0], &frame->uc.uc_osf_sigmask);
-        err |= __put_user(current->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
-        err |= __put_user(sas_ss_flags(oldsp), &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, oldsp);
         err |= setup_sigcontext(&frame->uc.uc_mcontext, regs, 
                                 set->sig[0], oldsp);
         err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));