From 069923d87e97a26d5f4ee2d53829f2d3cd05294b Mon Sep 17 00:00:00 2001 From: Andy Lutomirski Date: Tue, 22 Mar 2016 14:24:46 -0700 Subject: [PATCH] sparc/compat: provide an accurate in_compat_syscall implementation On sparc64 compat-enabled kernels, any task can make 32-bit and 64-bit syscalls. is_compat_task returns true in 32-bit tasks, which does not necessarily imply that the current syscall is 32-bit. Provide an in_compat_syscall implementation that checks whether the current syscall is compat. As far as I know, sparc is the only architecture on which is_compat_task checks the compat status of the task and on which the compat status of a syscall can differ from the compat status of the task. On x86, is_compat_task checks the syscall type, not the task type. [akpm@linux-foundation.org: add comment, per Sam] [akpm@linux-foundation.org: update comment, per Andy] Signed-off-by: Andy Lutomirski Acked-by: David S. Miller Cc: Sam Ravnborg Cc: Andy Lutomirski Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/sparc/include/asm/compat.h | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/arch/sparc/include/asm/compat.h b/arch/sparc/include/asm/compat.h index 830502fe62b4..6f251c4d613e 100644 --- a/arch/sparc/include/asm/compat.h +++ b/arch/sparc/include/asm/compat.h @@ -307,4 +307,11 @@ static inline int is_compat_task(void) return test_thread_flag(TIF_32BIT); } +static inline bool in_compat_syscall(void) +{ + /* Vector 0x110 is LINUX_32BIT_SYSCALL_TRAP */ + return pt_regs_trap_type(current_pt_regs()) == 0x110; +} +#define in_compat_syscall in_compat_syscall + #endif /* _ASM_SPARC64_COMPAT_H */