diff options
Diffstat (limited to 'common/recipes-kernel/linux/linux-yocto-4.9.21/0035-x86-process-Optimize-TIF-checks-in-__switch_to_xtra.patch')
| -rw-r--r-- | common/recipes-kernel/linux/linux-yocto-4.9.21/0035-x86-process-Optimize-TIF-checks-in-__switch_to_xtra.patch | 125 |
1 files changed, 0 insertions, 125 deletions
diff --git a/common/recipes-kernel/linux/linux-yocto-4.9.21/0035-x86-process-Optimize-TIF-checks-in-__switch_to_xtra.patch b/common/recipes-kernel/linux/linux-yocto-4.9.21/0035-x86-process-Optimize-TIF-checks-in-__switch_to_xtra.patch deleted file mode 100644 index bcbf8f92..00000000 --- a/common/recipes-kernel/linux/linux-yocto-4.9.21/0035-x86-process-Optimize-TIF-checks-in-__switch_to_xtra.patch +++ /dev/null @@ -1,125 +0,0 @@ -From ac5c35e60743b4260df777cc4ac1e877c2999b1d Mon Sep 17 00:00:00 2001 -From: Kyle Huey <me@kylehuey.com> -Date: Tue, 14 Feb 2017 00:11:02 -0800 -Subject: [PATCH 35/93] x86/process: Optimize TIF checks in __switch_to_xtra() - -commit af8b3cd3934ec60f4c2a420d19a9d416554f140b upstream - -Help the compiler to avoid reevaluating the thread flags for each checked -bit by reordering the bit checks and providing an explicit xor for -evaluation. - -With default defconfigs for each arch, - -x86_64: arch/x86/kernel/process.o -text data bss dec hex -3056 8577 16 11649 2d81 Before -3024 8577 16 11617 2d61 After - -i386: arch/x86/kernel/process.o -text data bss dec hex -2957 8673 8 11638 2d76 Before -2925 8673 8 11606 2d56 After - -Originally-by: Thomas Gleixner <tglx@linutronix.de> -Signed-off-by: Kyle Huey <khuey@kylehuey.com> -Cc: Peter Zijlstra <peterz@infradead.org> -Cc: Andy Lutomirski <luto@kernel.org> -Link: http://lkml.kernel.org/r/20170214081104.9244-2-khuey@kylehuey.com -Signed-off-by: Thomas Gleixner <tglx@linutronix.de> - -[dwmw2: backported to make TIF_RDS handling simpler. - No deferred TR reload.] -Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> -Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> ---- - arch/x86/kernel/process.c | 54 +++++++++++++++++++++++++++-------------------- - 1 file changed, 31 insertions(+), 23 deletions(-) - -diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c -index a55b320..0e1999e 100644 ---- a/arch/x86/kernel/process.c -+++ b/arch/x86/kernel/process.c -@@ -192,48 +192,56 @@ int set_tsc_mode(unsigned int val) - return 0; - } - -+static inline void switch_to_bitmap(struct tss_struct *tss, -+ struct thread_struct *prev, -+ struct thread_struct *next, -+ unsigned long tifp, unsigned long tifn) -+{ -+ if (tifn & _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 (tifp & _TIF_IO_BITMAP) { -+ /* -+ * Clear any possible leftover bits: -+ */ -+ memset(tss->io_bitmap, 0xff, prev->io_bitmap_max); -+ } -+} -+ - void __switch_to_xtra(struct task_struct *prev_p, struct task_struct *next_p, - struct tss_struct *tss) - { - struct thread_struct *prev, *next; -+ unsigned long tifp, tifn; - - prev = &prev_p->thread; - next = &next_p->thread; - -- if (test_tsk_thread_flag(prev_p, TIF_BLOCKSTEP) ^ -- test_tsk_thread_flag(next_p, TIF_BLOCKSTEP)) { -+ tifn = READ_ONCE(task_thread_info(next_p)->flags); -+ tifp = READ_ONCE(task_thread_info(prev_p)->flags); -+ switch_to_bitmap(tss, prev, next, tifp, tifn); -+ -+ propagate_user_return_notify(prev_p, next_p); -+ -+ if ((tifp ^ tifn) & _TIF_BLOCKSTEP) { - unsigned long debugctl = get_debugctlmsr(); - - debugctl &= ~DEBUGCTLMSR_BTF; -- if (test_tsk_thread_flag(next_p, TIF_BLOCKSTEP)) -+ if (tifn & _TIF_BLOCKSTEP) - debugctl |= DEBUGCTLMSR_BTF; -- - update_debugctlmsr(debugctl); - } - -- if (test_tsk_thread_flag(prev_p, TIF_NOTSC) ^ -- test_tsk_thread_flag(next_p, TIF_NOTSC)) { -- /* prev and next are different */ -- if (test_tsk_thread_flag(next_p, TIF_NOTSC)) -+ if ((tifp ^ tifn) & _TIF_NOTSC) { -+ if (tifn & _TIF_NOTSC) - hard_disable_TSC(); - else - 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); -- } -- propagate_user_return_notify(prev_p, next_p); - } - - /* --- -2.7.4 - |