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| author | Thomas Gleixner <tglx@linutronix.de> | 2019-11-11 23:03:23 +0100 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2019-11-16 11:24:03 +0100 |
| commit | 22fe5b0439dd53643fd6f4c582c46c6dba0fde53 (patch) | |
| tree | e74ed4d8d8f6182811570d21185a7703e76e56d7 /arch/x86/include/asm | |
| parent | 060aa16fdb7c5078a4159a76e5dc87d6a493af9b (diff) | |
| download | linux-22fe5b0439dd53643fd6f4c582c46c6dba0fde53.tar.bz2 | |
x86/ioperm: Move TSS bitmap update to exit to user work
There is no point to update the TSS bitmap for tasks which use I/O bitmaps
on every context switch. It's enough to update it right before exiting to
user space.
That reduces the context switch bitmap handling to invalidating the io
bitmap base offset in the TSS when the outgoing task has TIF_IO_BITMAP
set. The invaldiation is done on purpose when a task with an IO bitmap
switches out to prevent any possible leakage of an activated IO bitmap.
It also removes the requirement to update the tasks bitmap atomically in
ioperm().
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'arch/x86/include/asm')
| -rw-r--r-- | arch/x86/include/asm/io_bitmap.h | 2 | ||||
| -rw-r--r-- | arch/x86/include/asm/thread_info.h | 9 |
2 files changed, 7 insertions, 4 deletions
diff --git a/arch/x86/include/asm/io_bitmap.h b/arch/x86/include/asm/io_bitmap.h index d63bd5afe671..6d82a37cb17c 100644 --- a/arch/x86/include/asm/io_bitmap.h +++ b/arch/x86/include/asm/io_bitmap.h @@ -11,4 +11,6 @@ struct io_bitmap { unsigned long bitmap[IO_BITMAP_LONGS]; }; +void tss_update_io_bitmap(void); + #endif diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h index f9453536f9bb..0accf44878a5 100644 --- a/arch/x86/include/asm/thread_info.h +++ b/arch/x86/include/asm/thread_info.h @@ -143,8 +143,8 @@ struct thread_info { _TIF_NOHZ) /* flags to check in __switch_to() */ -#define _TIF_WORK_CTXSW_BASE \ - (_TIF_IO_BITMAP|_TIF_NOCPUID|_TIF_NOTSC|_TIF_BLOCKSTEP| \ +#define _TIF_WORK_CTXSW_BASE \ + (_TIF_NOCPUID | _TIF_NOTSC | _TIF_BLOCKSTEP | \ _TIF_SSBD | _TIF_SPEC_FORCE_UPDATE) /* @@ -156,8 +156,9 @@ struct thread_info { # define _TIF_WORK_CTXSW (_TIF_WORK_CTXSW_BASE) #endif -#define _TIF_WORK_CTXSW_PREV (_TIF_WORK_CTXSW|_TIF_USER_RETURN_NOTIFY) -#define _TIF_WORK_CTXSW_NEXT (_TIF_WORK_CTXSW) +#define _TIF_WORK_CTXSW_PREV (_TIF_WORK_CTXSW| _TIF_USER_RETURN_NOTIFY | \ + _TIF_IO_BITMAP) +#define _TIF_WORK_CTXSW_NEXT (_TIF_WORK_CTXSW) #define STACK_WARN (THREAD_SIZE/8) |