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

6 files changed, 75 insertions, 15 deletions

diff --git a/include/linux/binfmts.h b/include/linux/binfmts.h
index a4c2b565c835..cf3eae0b4f59 100644
--- a/include/linux/binfmts.h
+++ b/include/linux/binfmts.h
@@ -119,8 +119,4 @@ extern void install_exec_creds(struct linux_binprm *bprm);
 extern void set_binfmt(struct linux_binfmt *new);
 extern void free_bprm(struct linux_binprm *);
 
-#ifdef __ARCH_WANT_KERNEL_EXECVE
-extern void ret_from_kernel_execve(struct pt_regs *normal) __noreturn;
-#endif
-
 #endif /* _LINUX_BINFMTS_H */
diff --git a/include/linux/compat.h b/include/linux/compat.h
index e4920bd58a47..dec7e2d18875 100644
--- a/include/linux/compat.h
+++ b/include/linux/compat.h
@@ -23,6 +23,61 @@
 #define COMPAT_USE_64BIT_TIME 0
 #endif
 
+#ifndef __SC_DELOUSE
+#define __SC_DELOUSE(t,v) ((t)(unsigned long)(v))
+#endif
+
+#define __SC_CCAST1(t1, a1)      __SC_DELOUSE(t1,a1)
+#define __SC_CCAST2(t2, a2, ...) __SC_DELOUSE(t2,a2), __SC_CCAST1(__VA_ARGS__)
+#define __SC_CCAST3(t3, a3, ...) __SC_DELOUSE(t3,a3), __SC_CCAST2(__VA_ARGS__)
+#define __SC_CCAST4(t4, a4, ...) __SC_DELOUSE(t4,a4), __SC_CCAST3(__VA_ARGS__)
+#define __SC_CCAST5(t5, a5, ...) __SC_DELOUSE(t5,a5), __SC_CCAST4(__VA_ARGS__)
+#define __SC_CCAST6(t6, a6, ...) __SC_DELOUSE(t6,a6), __SC_CCAST5(__VA_ARGS__)
+#define COMPAT_SYSCALL_DEFINE1(name, ...) \
+        COMPAT_SYSCALL_DEFINEx(1, _##name, __VA_ARGS__)
+#define COMPAT_SYSCALL_DEFINE2(name, ...) \
+        COMPAT_SYSCALL_DEFINEx(2, _##name, __VA_ARGS__)
+#define COMPAT_SYSCALL_DEFINE3(name, ...) \
+        COMPAT_SYSCALL_DEFINEx(3, _##name, __VA_ARGS__)
+#define COMPAT_SYSCALL_DEFINE4(name, ...) \
+        COMPAT_SYSCALL_DEFINEx(4, _##name, __VA_ARGS__)
+#define COMPAT_SYSCALL_DEFINE5(name, ...) \
+        COMPAT_SYSCALL_DEFINEx(5, _##name, __VA_ARGS__)
+#define COMPAT_SYSCALL_DEFINE6(name, ...) \
+        COMPAT_SYSCALL_DEFINEx(6, _##name, __VA_ARGS__)
+
+#ifdef CONFIG_HAVE_SYSCALL_WRAPPERS
+
+#define COMPAT_SYSCALL_DEFINEx(x, name, ...)                            \
+        asmlinkage long compat_sys##name(__SC_DECL##x(__VA_ARGS__));    \
+        static inline long C_SYSC##name(__SC_DECL##x(__VA_ARGS__));     \
+        asmlinkage long compat_SyS##name(__SC_LONG##x(__VA_ARGS__))     \
+        {                                                               \
+                return (long) C_SYSC##name(__SC_CCAST##x(__VA_ARGS__)); \
+        }                                                               \
+        SYSCALL_ALIAS(compat_sys##name, compat_SyS##name);              \
+        static inline long C_SYSC##name(__SC_DECL##x(__VA_ARGS__))
+
+#else /* CONFIG_HAVE_SYSCALL_WRAPPERS */
+
+#define COMPAT_SYSCALL_DEFINEx(x, name, ...)                            \
+        asmlinkage long compat_sys##name(__SC_DECL##x(__VA_ARGS__))
+
+#endif /* CONFIG_HAVE_SYSCALL_WRAPPERS */
+
+#ifndef compat_user_stack_pointer
+#define compat_user_stack_pointer() current_user_stack_pointer()
+#endif
+#ifdef CONFIG_GENERIC_SIGALTSTACK
+#ifndef compat_sigaltstack      /* we'll need that for MIPS */
+typedef struct compat_sigaltstack {
+        compat_uptr_t                   ss_sp;
+        int                             ss_flags;
+        compat_size_t                   ss_size;
+} compat_stack_t;
+#endif
+#endif
+
 #define compat_jiffies_to_clock_t(x)    \
                 (((unsigned long)(x) * COMPAT_USER_HZ) / HZ)
 
@@ -587,6 +642,13 @@ asmlinkage ssize_t compat_sys_process_vm_writev(compat_pid_t pid,
 
 asmlinkage long compat_sys_sendfile(int out_fd, int in_fd,
                                     compat_off_t __user *offset, compat_size_t count);
+#ifdef CONFIG_GENERIC_SIGALTSTACK
+asmlinkage long compat_sys_sigaltstack(const compat_stack_t __user *uss_ptr,
+                                       compat_stack_t __user *uoss_ptr);
+
+int compat_restore_altstack(const compat_stack_t __user *uss);
+int __compat_save_altstack(compat_stack_t __user *, unsigned long);
+#endif
 
 asmlinkage long compat_sys_sched_rr_get_interval(compat_pid_t pid,
                                                  struct compat_timespec __user *interval);
diff --git a/include/linux/ptrace.h b/include/linux/ptrace.h
index addfbe7c180e..1693775ecfe8 100644
--- a/include/linux/ptrace.h
+++ b/include/linux/ptrace.h
@@ -344,6 +344,10 @@ static inline void user_single_step_siginfo(struct task_struct *tsk,
 #define signal_pt_regs() task_pt_regs(current)
 #endif
 
+#ifndef current_user_stack_pointer
+#define current_user_stack_pointer() user_stack_pointer(current_pt_regs())
+#endif
+
 extern int task_current_syscall(struct task_struct *target, long *callno,
                                 unsigned long args[6], unsigned int maxargs,
                                 unsigned long *sp, unsigned long *pc);
diff --git a/include/linux/sched.h b/include/linux/sched.h
index f712465b05c5..206bb089c06b 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -2353,9 +2353,7 @@ extern int do_execve(const char *,
                      const char __user * const __user *);
 extern long do_fork(unsigned long, unsigned long, unsigned long, int __user *, int __user *);
 struct task_struct *fork_idle(int);
-#ifdef CONFIG_GENERIC_KERNEL_THREAD
 extern pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags);
-#endif
 
 extern void set_task_comm(struct task_struct *tsk, char *from);
 extern char *get_task_comm(char *to, struct task_struct *tsk);
diff --git a/include/linux/signal.h b/include/linux/signal.h
index e19a011b43b7..0a89ffc48466 100644
--- a/include/linux/signal.h
+++ b/include/linux/signal.h
@@ -385,4 +385,7 @@ int unhandled_signal(struct task_struct *tsk, int sig);
 
 void signals_init(void);
 
+int restore_altstack(const stack_t __user *);
+int __save_altstack(stack_t __user *, unsigned long);
+
 #endif /* _LINUX_SIGNAL_H */
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 6caee34bf8a2..45e2db270255 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -63,6 +63,7 @@ struct getcpu_cache;
 struct old_linux_dirent;
 struct perf_event_attr;
 struct file_handle;
+struct sigaltstack;
 
 #include <linux/types.h>
 #include <linux/aio_abi.h>
@@ -299,6 +300,11 @@ asmlinkage long sys_personality(unsigned int personality);
 asmlinkage long sys_sigpending(old_sigset_t __user *set);
 asmlinkage long sys_sigprocmask(int how, old_sigset_t __user *set,
                                 old_sigset_t __user *oset);
+#ifdef CONFIG_GENERIC_SIGALTSTACK
+asmlinkage long sys_sigaltstack(const struct sigaltstack __user *uss,
+                                struct sigaltstack __user *uoss);
+#endif
+
 asmlinkage long sys_getitimer(int which, struct itimerval __user *value);
 asmlinkage long sys_setitimer(int which,
                                 struct itimerval __user *value,
@@ -827,15 +833,6 @@ asmlinkage long sys_fanotify_mark(int fanotify_fd, unsigned int flags,
                                   const char  __user *pathname);
 asmlinkage long sys_syncfs(int fd);
 
-#ifndef CONFIG_GENERIC_KERNEL_EXECVE
-int kernel_execve(const char *filename, const char *const argv[], const char *const envp[]);
-#else
-#define kernel_execve(filename, argv, envp) \
-        do_execve(filename, \
-                (const char __user *const __user *)argv, \
-                (const char __user *const __user *)envp)
-#endif
-
 asmlinkage long sys_fork(void);
 asmlinkage long sys_vfork(void);
 #ifdef CONFIG_CLONE_BACKWARDS