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Date: Sun, 2 Nov 2014 09:32:55 -0800 From: Josh Triplett <josh@...htriplett.org> To: "H. Peter Anvin" <hpa@...or.com>, Ingo Molnar <mingo@...hat.com>, Kees Cook <keescook@...omium.org>, Thomas Gleixner <tglx@...utronix.de>, linux-kernel@...r.kernel.org, virtualization@...ts.linux-foundation.org, x86@...nel.org, xen-devel@...ts.xenproject.org Subject: [PATCH v4 09/10] x86: process: Introduce helper to switch IO bitmap This simplifies __switch_to_xtra, and will make it easier to make IO optional later. Signed-off-by: Josh Triplett <josh@...htriplett.org> --- arch/x86/kernel/process-io.h | 23 +++++++++++++++++++++++ arch/x86/kernel/process.c | 14 +------------- 2 files changed, 24 insertions(+), 13 deletions(-) diff --git a/arch/x86/kernel/process-io.h b/arch/x86/kernel/process-io.h index 012c1d5..e48d5c9 100644 --- a/arch/x86/kernel/process-io.h +++ b/arch/x86/kernel/process-io.h @@ -57,4 +57,27 @@ static inline void switch_iopl_mask(struct thread_struct *prev, set_iopl_mask(next->iopl); } +static inline void switch_io_bitmap(struct tss_struct *tss, + struct task_struct *prev_p, + struct task_struct *next_p) +{ + struct thread_struct *prev, *next; + prev = &prev_p->thread; + next = &next_p->thread; + + if (test_tsk_thread_flag(next_p, TIF_IO_BITMAP)) { + /* + * Copy the relevant range of the IO bitmap. + * Normally this is 128 bytes or less: + */ + memcpy(tss->io_bitmap, next->io_bitmap_ptr, + max(prev->io_bitmap_max, next->io_bitmap_max)); + } else if (test_tsk_thread_flag(prev_p, TIF_IO_BITMAP)) { + /* + * Clear any possible leftover bits: + */ + memset(tss->io_bitmap, 0xff, prev->io_bitmap_max); + } +} + #endif /* _X86_KERNEL_PROCESS_IO_H */ diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c index 37b45ca..7ac01bf 100644 --- a/arch/x86/kernel/process.c +++ b/arch/x86/kernel/process.c @@ -211,19 +211,7 @@ void __switch_to_xtra(struct task_struct *prev_p, struct task_struct *next_p, hard_enable_TSC(); } - if (test_tsk_thread_flag(next_p, TIF_IO_BITMAP)) { - /* - * Copy the relevant range of the IO bitmap. - * Normally this is 128 bytes or less: - */ - memcpy(tss->io_bitmap, next->io_bitmap_ptr, - max(prev->io_bitmap_max, next->io_bitmap_max)); - } else if (test_tsk_thread_flag(prev_p, TIF_IO_BITMAP)) { - /* - * Clear any possible leftover bits: - */ - memset(tss->io_bitmap, 0xff, prev->io_bitmap_max); - } + switch_io_bitmap(tss, prev_p, next_p); propagate_user_return_notify(prev_p, next_p); } -- 2.1.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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