diff options
Diffstat (limited to 'include/asm-i386/ptrace.h')
| -rw-r--r-- | include/asm-i386/ptrace.h | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/include/asm-i386/ptrace.h b/include/asm-i386/ptrace.h index 05532875e39e..7e0f2945d17d 100644 --- a/include/asm-i386/ptrace.h +++ b/include/asm-i386/ptrace.h @@ -61,6 +61,13 @@ struct pt_regs { struct task_struct; extern void send_sigtrap(struct task_struct *tsk, struct pt_regs *regs, int error_code); +/* + * user_mode_vm(regs) determines whether a register set came from user mode. + * This is true if V8086 mode was enabled OR if the register set was from + * protected mode with RPL-3 CS value. This tricky test checks that with + * one comparison. Many places in the kernel can bypass this full check + * if they have already ruled out V8086 mode, so user_mode(regs) can be used. + */ static inline int user_mode(struct pt_regs *regs) { return (regs->xcs & 3) != 0; |