[PATCH 3/3] [RFC] Revert "x86: remove the x32 syscall bitmask from syscall_get_nr()"

From: Richard Guy Briggs
Date: Thu Jul 10 2014 - 23:39:20 EST

This reverts commit 8b4b9f27e57584f3d90e0bb84cf800ad81cfe3a1.
which broke audit and potentially other users of syscall_get_nr() which depend
on that call as named without being overloaded by architecture bits.

This patch along with
seccomp: give BPF x32 bit when restoring x32 filter
will satisfy other regular users of syscall_get_nr() and syscall_get_arch()
without changing the seccomp interface to BPF.

Cc: Paul Moore <pmoore@xxxxxxxxxx>
Cc: Eric Paris <eparis@xxxxxxxxxx>
Cc: Al Viro <aviro@xxxxxxxxxx>
Cc: Will Drewry <wad@xxxxxxxxxxxx>
Cc: H. Peter Anvin <hpa@xxxxxxxxx>
Signed-off-by: Richard Guy Briggs <rgb@xxxxxxxxxx>
Link: http://lkml.kernel.org/r/cover.1405023592.git.rgb@xxxxxxxxxx
arch/x86/include/asm/syscall.h | 4 ++--
1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/syscall.h b/arch/x86/include/asm/syscall.h
index d58b6be..8c1bb2b 100644
--- a/arch/x86/include/asm/syscall.h
+++ b/arch/x86/include/asm/syscall.h
@@ -30,13 +30,13 @@ extern const sys_call_ptr_t sys_call_table[];
static inline int syscall_get_nr(struct task_struct *task, struct pt_regs *regs)
- return regs->orig_ax;
+ return regs->orig_ax & __SYSCALL_MASK;

static inline void syscall_rollback(struct task_struct *task,
struct pt_regs *regs)
- regs->ax = regs->orig_ax;
+ regs->ax = regs->orig_ax & __SYSCALL_MASK;

static inline long syscall_get_error(struct task_struct *task,

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