lkml.org 
[lkml]   [2020]   [Nov]   [16]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[tip: core/entry] entry: Drop usage of TIF flags in the generic syscall code
The following commit has been merged into the core/entry branch of tip:

Commit-ID: 2991552447707d791d9d81a5dc161f9e9e90b163
Gitweb: https://git.kernel.org/tip/2991552447707d791d9d81a5dc161f9e9e90b163
Author: Gabriel Krisman Bertazi <krisman@collabora.com>
AuthorDate: Mon, 16 Nov 2020 12:42:05 -05:00
Committer: Thomas Gleixner <tglx@linutronix.de>
CommitterDate: Mon, 16 Nov 2020 21:53:16 +01:00

entry: Drop usage of TIF flags in the generic syscall code

Now that the flags migration in the common syscall entry code is complete
and the code relies exclusively on thread_info::syscall_work, clean up the
accesses to TI flags in that path.

Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Andy Lutomirski <luto@kernel.org>
Link: https://lore.kernel.org/r/20201116174206.2639648-10-krisman@collabora.com
---
include/linux/entry-common.h | 26 ++++++++++++--------------
kernel/entry/common.c | 17 +++++++----------
2 files changed, 19 insertions(+), 24 deletions(-)

diff --git a/include/linux/entry-common.h b/include/linux/entry-common.h
index d7b96f4..49b26b2 100644
--- a/include/linux/entry-common.h
+++ b/include/linux/entry-common.h
@@ -26,31 +26,29 @@
#endif

/*
- * TIF flags handled in syscall_enter_from_user_mode()
+ * SYSCALL_WORK flags handled in syscall_enter_from_user_mode()
*/
-#ifndef ARCH_SYSCALL_ENTER_WORK
-# define ARCH_SYSCALL_ENTER_WORK (0)
+#ifndef ARCH_SYSCALL_WORK_ENTER
+# define ARCH_SYSCALL_WORK_ENTER (0)
#endif

-#define SYSCALL_ENTER_WORK ARCH_SYSCALL_ENTER_WORK
-
/*
- * TIF flags handled in syscall_exit_to_user_mode()
+ * SYSCALL_WORK flags handled in syscall_exit_to_user_mode()
*/
-#ifndef ARCH_SYSCALL_EXIT_WORK
-# define ARCH_SYSCALL_EXIT_WORK (0)
+#ifndef ARCH_SYSCALL_WORK_EXIT
+# define ARCH_SYSCALL_WORK_EXIT (0)
#endif

-#define SYSCALL_EXIT_WORK ARCH_SYSCALL_EXIT_WORK
-
#define SYSCALL_WORK_ENTER (SYSCALL_WORK_SECCOMP | \
SYSCALL_WORK_SYSCALL_TRACEPOINT | \
SYSCALL_WORK_SYSCALL_TRACE | \
SYSCALL_WORK_SYSCALL_EMU | \
- SYSCALL_WORK_SYSCALL_AUDIT)
+ SYSCALL_WORK_SYSCALL_AUDIT | \
+ ARCH_SYSCALL_WORK_ENTER)
#define SYSCALL_WORK_EXIT (SYSCALL_WORK_SYSCALL_TRACEPOINT | \
SYSCALL_WORK_SYSCALL_TRACE | \
- SYSCALL_WORK_SYSCALL_AUDIT)
+ SYSCALL_WORK_SYSCALL_AUDIT | \
+ ARCH_SYSCALL_WORK_EXIT)

/*
* TIF flags handled in exit_to_user_mode_loop()
@@ -136,8 +134,8 @@ void syscall_enter_from_user_mode_prepare(struct pt_regs *regs);
*
* It handles the following work items:
*
- * 1) TIF flag dependent invocations of arch_syscall_enter_tracehook(),
- * __secure_computing(), trace_sys_enter()
+ * 1) syscall_work flag dependent invocations of
+ * arch_syscall_enter_tracehook(), __secure_computing(), trace_sys_enter()
* 2) Invocation of audit_syscall_entry()
*/
long syscall_enter_from_user_mode_work(struct pt_regs *regs, long syscall);
diff --git a/kernel/entry/common.c b/kernel/entry/common.c
index 90533f3..91e8fd5 100644
--- a/kernel/entry/common.c
+++ b/kernel/entry/common.c
@@ -42,7 +42,7 @@ static inline void syscall_enter_audit(struct pt_regs *regs, long syscall)
}

static long syscall_trace_enter(struct pt_regs *regs, long syscall,
- unsigned long ti_work, unsigned long work)
+ unsigned long work)
{
long ret = 0;

@@ -75,11 +75,9 @@ static __always_inline long
__syscall_enter_from_user_work(struct pt_regs *regs, long syscall)
{
unsigned long work = READ_ONCE(current_thread_info()->syscall_work);
- unsigned long ti_work;

- ti_work = READ_ONCE(current_thread_info()->flags);
- if (work & SYSCALL_WORK_ENTER || ti_work & SYSCALL_ENTER_WORK)
- syscall = syscall_trace_enter(regs, syscall, ti_work, work);
+ if (work & SYSCALL_WORK_ENTER)
+ syscall = syscall_trace_enter(regs, syscall, work);

return syscall;
}
@@ -227,8 +225,8 @@ static inline bool report_single_step(unsigned long work)
}
#endif

-static void syscall_exit_work(struct pt_regs *regs, unsigned long ti_work,
- unsigned long work)
+
+static void syscall_exit_work(struct pt_regs *regs, unsigned long work)
{
bool step;

@@ -249,7 +247,6 @@ static void syscall_exit_work(struct pt_regs *regs, unsigned long ti_work,
static void syscall_exit_to_user_mode_prepare(struct pt_regs *regs)
{
unsigned long work = READ_ONCE(current_thread_info()->syscall_work);
- u32 cached_flags = READ_ONCE(current_thread_info()->flags);
unsigned long nr = syscall_get_nr(current, regs);

CT_WARN_ON(ct_state() != CONTEXT_KERNEL);
@@ -266,8 +263,8 @@ static void syscall_exit_to_user_mode_prepare(struct pt_regs *regs)
* enabled, we want to run them exactly once per syscall exit with
* interrupts enabled.
*/
- if (unlikely(work & SYSCALL_WORK_EXIT || cached_flags & SYSCALL_EXIT_WORK))
- syscall_exit_work(regs, cached_flags, work);
+ if (unlikely(work & SYSCALL_WORK_EXIT))
+ syscall_exit_work(regs, work);
}

__visible noinstr void syscall_exit_to_user_mode(struct pt_regs *regs)
\
 
 \ /
  Last update: 2020-11-16 22:12    [W:0.184 / U:0.084 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site