From bd1c149aa9915b9abb6d83d0f01dfd2ace0680b5 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Sun, 1 Sep 2013 20:35:01 +0100 Subject: Introduce [compat_]save_altstack_ex() to unbreak x86 SMAP For performance reasons, when SMAP is in use, SMAP is left open for an entire put_user_try { ... } put_user_catch(); block, however, calling __put_user() in the middle of that block will close SMAP as the STAC..CLAC constructs intentionally do not nest. Furthermore, using __put_user() rather than put_user_ex() here is bad for performance. Thus, introduce new [compat_]save_altstack_ex() helpers that replace __[compat_]save_altstack() for x86, being currently the only architecture which supports put_user_try { ... } put_user_catch(). Reported-by: H. Peter Anvin Signed-off-by: Al Viro Signed-off-by: H. Peter Anvin Cc: # v3.8+ Link: http://lkml.kernel.org/n/tip-es5p6y64if71k8p5u08agv9n@git.kernel.org --- include/linux/compat.h | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'include/linux/compat.h') diff --git a/include/linux/compat.h b/include/linux/compat.h index 7f0c1dd09079..ec1aee4aec9c 100644 --- a/include/linux/compat.h +++ b/include/linux/compat.h @@ -669,6 +669,13 @@ asmlinkage long compat_sys_sigaltstack(const compat_stack_t __user *uss_ptr, int compat_restore_altstack(const compat_stack_t __user *uss); int __compat_save_altstack(compat_stack_t __user *, unsigned long); +#define compat_save_altstack_ex(uss, sp) do { \ + compat_stack_t __user *__uss = uss; \ + struct task_struct *t = current; \ + put_user_ex(ptr_to_compat((void __user *)t->sas_ss_sp), &__uss->ss_sp); \ + put_user_ex(sas_ss_flags(sp), &__uss->ss_flags); \ + put_user_ex(t->sas_ss_size, &__uss->ss_size); \ +} while (0); asmlinkage long compat_sys_sched_rr_get_interval(compat_pid_t pid, struct compat_timespec __user *interval); -- cgit v1.2.3 From f9597f24c089dcbddbd2d9e99fbf00df57fb70c6 Mon Sep 17 00:00:00 2001 From: Sergei Trofimovich Date: Wed, 11 Sep 2013 14:23:28 -0700 Subject: syscalls.h: add forward declarations for inplace syscall wrappers Unclutter -Wmissing-prototypes warning types (enabled at make W=1) linux/include/linux/syscalls.h:190:18: warning: no previous prototype for 'SyS_semctl' [-Wmissing-prototypes] asmlinkage long SyS##name(__MAP(x,__SC_LONG,__VA_ARGS__)) \ ^ linux/include/linux/syscalls.h:183:2: note: in expansion of macro '__SYSCALL_DEFINEx' __SYSCALL_DEFINEx(x, sname, __VA_ARGS__) ^ by adding forward declarations right before definitions. Signed-off-by: Sergei Trofimovich Cc: Al Viro Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/compat.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux/compat.h') diff --git a/include/linux/compat.h b/include/linux/compat.h index ec1aee4aec9c..345da00a86e0 100644 --- a/include/linux/compat.h +++ b/include/linux/compat.h @@ -43,6 +43,7 @@ #define COMPAT_SYSCALL_DEFINEx(x, name, ...) \ asmlinkage long compat_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__));\ static inline long C_SYSC##name(__MAP(x,__SC_DECL,__VA_ARGS__));\ + asmlinkage long compat_SyS##name(__MAP(x,__SC_LONG,__VA_ARGS__));\ asmlinkage long compat_SyS##name(__MAP(x,__SC_LONG,__VA_ARGS__))\ { \ return C_SYSC##name(__MAP(x,__SC_DELOUSE,__VA_ARGS__)); \ -- cgit v1.2.3