From 22fe5b0439dd53643fd6f4c582c46c6dba0fde53 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Mon, 11 Nov 2019 23:03:23 +0100 Subject: 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 --- arch/x86/include/asm/io_bitmap.h | 2 ++ arch/x86/include/asm/thread_info.h | 9 +++++---- 2 files changed, 7 insertions(+), 4 deletions(-) (limited to 'arch/x86/include/asm') 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) -- cgit v1.2.3