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| author | Chris Metcalf <cmetcalf@ezchip.com> | 2015-09-22 21:49:41 +0300 |
|---|---|---|
| committer | Chris Metcalf <cmetcalf@ezchip.com> | 2016-01-18 22:49:09 +0300 |
| commit | 583b24a210ada7e88fc12aaf50024975ec882816 (patch) | |
| tree | b396bc95a44f29d9dd2c8bab86fcd0d0728b24b1 /arch/tile/include/asm | |
| parent | 65a792e84f25d1436698f999224b2cf5d7594546 (diff) | |
| download | linux-583b24a210ada7e88fc12aaf50024975ec882816.tar.xz | |
arch/tile: adopt prepare_exit_to_usermode() model from x86
This change is a prerequisite change for TASK_ISOLATION but also
stands on its own for readability and maintainability. The existing
tile do_work_pending() was called in a loop from assembly on
the slow path; this change moves the loop into C code as well.
For the x86 version see commit c5c46f59e4e7 ("x86/entry: Add new,
comprehensible entry and exit handlers written in C").
This change exposes a pre-existing bug on the older tilepro platform;
the singlestep processing is done last, but on tilepro (unlike tilegx)
we enable interrupts while doing that processing, so we could in
theory miss a signal or other asynchronous event. A future change
could fix this by breaking the singlestep work into a "prepare"
step done in the main loop, and a "trigger" step done after exiting
the loop. Since this change is intended as purely a restructuring
change, we call out the bug explicitly now, but don't yet fix it.
Signed-off-by: Chris Metcalf <cmetcalf@ezchip.com>
Diffstat (limited to 'arch/tile/include/asm')
| -rw-r--r-- | arch/tile/include/asm/processor.h | 2 | ||||
| -rw-r--r-- | arch/tile/include/asm/thread_info.h | 8 |
2 files changed, 7 insertions, 3 deletions
diff --git a/arch/tile/include/asm/processor.h b/arch/tile/include/asm/processor.h index 139dfdee0134..0684e88aacd8 100644 --- a/arch/tile/include/asm/processor.h +++ b/arch/tile/include/asm/processor.h @@ -212,7 +212,7 @@ static inline void release_thread(struct task_struct *dead_task) /* Nothing for now */ } -extern int do_work_pending(struct pt_regs *regs, u32 flags); +extern void prepare_exit_to_usermode(struct pt_regs *regs, u32 flags); /* diff --git a/arch/tile/include/asm/thread_info.h b/arch/tile/include/asm/thread_info.h index dc1fb28d9636..4b7cef9e94e0 100644 --- a/arch/tile/include/asm/thread_info.h +++ b/arch/tile/include/asm/thread_info.h @@ -140,10 +140,14 @@ extern void _cpu_idle(void); #define _TIF_POLLING_NRFLAG (1<<TIF_POLLING_NRFLAG) #define _TIF_NOHZ (1<<TIF_NOHZ) +/* Work to do as we loop to exit to user space. */ +#define _TIF_WORK_MASK \ + (_TIF_SIGPENDING | _TIF_NEED_RESCHED | \ + _TIF_ASYNC_TLB | _TIF_NOTIFY_RESUME) + /* Work to do on any return to user space. */ #define _TIF_ALLWORK_MASK \ - (_TIF_SIGPENDING | _TIF_NEED_RESCHED | _TIF_SINGLESTEP | \ - _TIF_ASYNC_TLB | _TIF_NOTIFY_RESUME | _TIF_NOHZ) + (_TIF_WORK_MASK | _TIF_SINGLESTEP | _TIF_NOHZ) /* Work to do at syscall entry. */ #define _TIF_SYSCALL_ENTRY_WORK \ |