[tip: x86/entry] x86/ptrace: Provide pt_regs helper for entry/exit

[tip-bot2 for Thomas Gleixner]

The following commit has been merged into the x86/entry branch of tip:

Commit-ID:     0bf019ea59e330770883ede4499d7f711d8c3adf
Gitweb:        https://git.kernel.org/tip/0bf019ea59e330770883ede4499d7f711d8c3adf
Author:        Thomas Gleixner <tglx@xxxxxxxxxxxxx>
AuthorDate:    Thu, 23 Jul 2020 00:00:03 +02:00
Committer:     Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitterDate: Fri, 24 Jul 2020 15:04:58 +02:00

x86/ptrace: Provide pt_regs helper for entry/exit

As a preparatory step for moving the syscall and interrupt entry/exit
handling into generic code, provide a pt_regs helper which retrieves the
interrupt state from pt_regs. This is required to check whether interrupts
are reenabled by return from interrupt/exception.

Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx>
Link: https://lkml.kernel.org/r/20200722220520.258511584@xxxxxxxxxxxxx


---
 arch/x86/include/asm/ptrace.h | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/arch/x86/include/asm/ptrace.h b/arch/x86/include/asm/ptrace.h
index 255b2dd..40aa69d 100644
--- a/arch/x86/include/asm/ptrace.h
+++ b/arch/x86/include/asm/ptrace.h
@@ -209,6 +209,11 @@ static inline void user_stack_pointer_set(struct pt_regs *regs,
 	regs->sp = val;
 }
 
+static __always_inline bool regs_irqs_disabled(struct pt_regs *regs)
+{
+	return !(regs->flags & X86_EFLAGS_IF);
+}
+
 /* Query offset/name of register from its name/offset */
 extern int regs_query_register_offset(const char *name);
 extern const char *regs_query_register_name(unsigned int offset);