diff options
Diffstat (limited to 'debian/patches-rt/0008-x86-fpu-Remove-user_fpu_begin.patch')
| -rw-r--r-- | debian/patches-rt/0008-x86-fpu-Remove-user_fpu_begin.patch | 83 |
1 files changed, 0 insertions, 83 deletions
diff --git a/debian/patches-rt/0008-x86-fpu-Remove-user_fpu_begin.patch b/debian/patches-rt/0008-x86-fpu-Remove-user_fpu_begin.patch deleted file mode 100644 index bcab836ce..000000000 --- a/debian/patches-rt/0008-x86-fpu-Remove-user_fpu_begin.patch +++ /dev/null @@ -1,83 +0,0 @@ -From: Sebastian Andrzej Siewior <bigeasy@linutronix.de> -Date: Thu, 18 Oct 2018 18:34:11 +0200 -Subject: [PATCH 08/27] x86/fpu: Remove user_fpu_begin() -Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.0/older/patches-5.0.10-rt7.tar.xz - -user_fpu_begin() sets fpu_fpregs_owner_ctx to task's fpu struct. This is -always the case since there is no lazy FPU anymore. - -fpu_fpregs_owner_ctx is used during context switch to decide if it needs -to load the saved registers or if the currently loaded registers are -valid. It could be skipped during - taskA -> kernel thread -> taskA - -because the switch to kernel thread would not alter the CPU's FPU state. - -Since this field is always updated during context switch and never -invalidated, setting it manually (in user context) makes no difference. -A kernel thread with kernel_fpu_begin() block could set -fpu_fpregs_owner_ctx to NULL but a kernel thread does not use -user_fpu_begin(). -This is a leftover from the lazy-FPU time. - -Remove user_fpu_begin(), it does not change fpu_fpregs_owner_ctx's -content. - -Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> -Reviewed-by: Borislav Petkov <bp@suse.de> ---- - arch/x86/include/asm/fpu/internal.h | 17 ----------------- - arch/x86/kernel/fpu/core.c | 4 +--- - arch/x86/kernel/fpu/signal.c | 1 - - 3 files changed, 1 insertion(+), 21 deletions(-) - ---- a/arch/x86/include/asm/fpu/internal.h -+++ b/arch/x86/include/asm/fpu/internal.h -@@ -564,23 +564,6 @@ static inline void switch_fpu_finish(str - } - - /* -- * Needs to be preemption-safe. -- * -- * NOTE! user_fpu_begin() must be used only immediately before restoring -- * the save state. It does not do any saving/restoring on its own. In -- * lazy FPU mode, it is just an optimization to avoid a #NM exception, -- * the task can lose the FPU right after preempt_enable(). -- */ --static inline void user_fpu_begin(void) --{ -- struct fpu *fpu = ¤t->thread.fpu; -- -- preempt_disable(); -- fpregs_activate(fpu); -- preempt_enable(); --} -- --/* - * MXCSR and XCR definitions: - */ - ---- a/arch/x86/kernel/fpu/core.c -+++ b/arch/x86/kernel/fpu/core.c -@@ -335,10 +335,8 @@ void fpu__clear(struct fpu *fpu) - * Make sure fpstate is cleared and initialized. - */ - fpu__initialize(fpu); -- if (static_cpu_has(X86_FEATURE_FPU)) { -- user_fpu_begin(); -+ if (static_cpu_has(X86_FEATURE_FPU)) - copy_init_fpstate_to_fpregs(); -- } - } - - /* ---- a/arch/x86/kernel/fpu/signal.c -+++ b/arch/x86/kernel/fpu/signal.c -@@ -322,7 +322,6 @@ static int __fpu__restore_sig(void __use - * For 64-bit frames and 32-bit fsave frames, restore the user - * state to the registers directly (with exceptions handled). - */ -- user_fpu_begin(); - if (copy_user_to_fpregs_zeroing(buf_fx, xfeatures, fx_only)) { - fpu__clear(fpu); - return -1; |