Change to v1:
removed whitespace changes and changed commit message
Am Fri, 14 Sep 2018 17:10:15 +0200
schrieb Henning Schild <henning.sch...@siemens.com>:
> Linux 4.14 dropped support for lazy fpu switching and in the 4.4 and
> 4.9 series similar changes where backported.
> So fpu is eager for those versions. That simplifies things a lot and
> we can drop several changes from the IPIPE patch.
> On the Xenomai side the only thing we still have to care about is the
> kernel fpu state when we interrupt an in kernel fpu user. But we do
> that explicit and can drop the indirection active_(fp)state.
>
> This patch basically drops most of the fpu specifics from the ipipe
> patch.
>
> This patch applies on ipipe-4.9.y and it has to be followed by a
> merge with
> >= 4.9.109. Cobalt will not compile if you are already eager and
> >still
> 4.9.108
>
> Signed-off-by: Henning Schild <henning.sch...@siemens.com>
> ---
> arch/x86/include/asm/fpu/internal.h | 30
> ++++++++--------------------- arch/x86/include/asm/fpu/types.h |
> 12 ------------ arch/x86/kernel/fpu/core.c | 17
> ++++++---------- arch/x86/kernel/fpu/init.c | 5 +----
> 4 files changed, 15 insertions(+), 49 deletions(-)
>
> diff --git a/arch/x86/include/asm/fpu/internal.h
> b/arch/x86/include/asm/fpu/internal.h index
> 35ca184e83e1..6bdceba90f17 100644 ---
> a/arch/x86/include/asm/fpu/internal.h +++
> b/arch/x86/include/asm/fpu/internal.h @@ -13,7 +13,6 @@
> #include <linux/compat.h>
> #include <linux/sched.h>
> #include <linux/slab.h>
> -#include <linux/kconfig.h>
> #include <linux/ipipe.h>
>
> #include <asm/user.h>
> @@ -190,24 +189,12 @@ static inline int copy_user_to_fregs(struct
> fregs_state __user *fx) return user_insn(frstor %[fx], "=m" (*fx),
> [fx] "m" (*fx)); }
>
> -#ifdef CONFIG_IPIPE
> -static inline union fpregs_state *active_fpstate(struct fpu *fpu)
> -{
> - return fpu->active_state;
> -}
> -#else
> -static inline union fpregs_state *active_fpstate(struct fpu *fpu)
> -{
> - return &fpu->state;
> -}
> -#endif
> -
> static inline void copy_fxregs_to_kernel(struct fpu *fpu)
> {
> if (IS_ENABLED(CONFIG_X86_32))
> - asm volatile( "fxsave %[fx]" : [fx]
> "=m" (active_fpstate(fpu)->fxsave));
> + asm volatile( "fxsave %[fx]" : [fx]
> "=m" (fpu->state.fxsave)); else if (IS_ENABLED(CONFIG_AS_FXSAVEQ))
> - asm volatile("fxsaveq %[fx]" : [fx]
> "=m" (active_fpstate(fpu)->fxsave));
> + asm volatile("fxsaveq %[fx]" : [fx]
> "=m" (fpu->state.fxsave)); else {
> /* Using "rex64; fxsave %0" is broken because, if
> the memory
> * operand uses any extended registers for
> addressing, a second @@ -231,8 +218,8 @@ static inline void
> copy_fxregs_to_kernel(struct fpu *fpu)
> * registers.
> */
> asm volatile( "rex64/fxsave (%[fx])"
> - : "=m" (active_fpstate(fpu)->fxsave)
> - : [fx]
> "R" (&active_fpstate(fpu)->fxsave));
> + : "=m" (fpu->state.fxsave)
> + : [fx] "R" (&fpu->state.fxsave));
> }
> }
>
> @@ -441,7 +428,7 @@ static inline int copy_user_to_xregs(struct
> xregs_state __user *buf, u64 mask) static inline int
> copy_fpregs_to_fpstate(struct fpu *fpu) {
> if (likely(use_xsave())) {
> - copy_xregs_to_kernel(&active_fpstate(fpu)->xsave);
> + copy_xregs_to_kernel(&fpu->state.xsave);
> return 1;
> }
>
> @@ -454,7 +441,7 @@ static inline int copy_fpregs_to_fpstate(struct
> fpu *fpu)
> * Legacy FPU register saving, FNSAVE always clears FPU
> registers,
> * so we have to mark them inactive:
> */
> - asm volatile("fnsave %[fp]; fwait" : [fp]
> "=m" (active_fpstate(fpu)->fsave));
> + asm volatile("fnsave %[fp]; fwait" : [fp]
> "=m" (fpu->state.fsave));
> return 0;
> }
> @@ -609,8 +596,7 @@ switch_fpu_prepare(struct fpu *old_fpu, struct
> fpu *new_fpu, int cpu)
> * If the task has used the math, pre-load the FPU on xsave
> processors
> * or if the past 5 consecutive context-switches used math.
> */
> - fpu.preload = !IS_ENABLED(CONFIG_IPIPE) &&
> - static_cpu_has(X86_FEATURE_FPU) &&
> + fpu.preload = static_cpu_has(X86_FEATURE_FPU) &&
> new_fpu->fpstate_active &&
> (use_eager_fpu() || new_fpu->counter > 5);
>
> @@ -660,7 +646,7 @@ switch_fpu_prepare(struct fpu *old_fpu, struct
> fpu *new_fpu, int cpu) */
> static inline void switch_fpu_finish(struct fpu *new_fpu,
> fpu_switch_t fpu_switch) {
> - if (!IS_ENABLED(CONFIG_IPIPE) && fpu_switch.preload)
> + if (fpu_switch.preload)
> copy_kernel_to_fpregs(&new_fpu->state);
> }
>
> diff --git a/arch/x86/include/asm/fpu/types.h
> b/arch/x86/include/asm/fpu/types.h index 497c551469ec..48df486b02f9
> 100644 --- a/arch/x86/include/asm/fpu/types.h
> +++ b/arch/x86/include/asm/fpu/types.h
> @@ -332,18 +332,6 @@ struct fpu {
> * deal with bursty apps that only use the FPU for a short
> time: */
> unsigned char counter;
> -
> -#ifdef CONFIG_IPIPE
> - /*
> - * @active_state
> - *
> - * An indirection pointer to reach the active state context
> - * for the task. This is used by co-kernels for dealing with
> - * preemption of kernel fpu contexts by their own tasks.
> - */
> - union fpregs_state *active_state;
> -#endif
> -
> /*
> * @state:
> *
> diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c
> index d31a73b2ab76..7dd8518272ca 100644
> --- a/arch/x86/kernel/fpu/core.c
> +++ b/arch/x86/kernel/fpu/core.c
> @@ -124,7 +124,7 @@ void __kernel_fpu_end(void)
>
> flags = hard_cond_local_irq_save();
> if (fpu->fpregs_active)
> - copy_kernel_to_fpregs(active_fpstate(fpu));
> + copy_kernel_to_fpregs(&fpu->state);
> else
> __fpregs_deactivate_hw();
>
> @@ -192,7 +192,7 @@ void fpu__save(struct fpu *fpu)
> if (fpu->fpregs_active) {
> if (!copy_fpregs_to_fpstate(fpu)) {
> if (use_eager_fpu())
> -
> copy_kernel_to_fpregs(active_fpstate(fpu));
> + copy_kernel_to_fpregs(&fpu->state);
> else
> fpregs_deactivate(fpu);
> }
> @@ -244,13 +244,8 @@ int fpu__copy(struct fpu *dst_fpu, struct fpu
> *src_fpu) dst_fpu->counter = 0;
> dst_fpu->fpregs_active = 0;
> dst_fpu->last_cpu = -1;
> -#ifdef CONFIG_IPIPE
> - /* Must be set before FPU context is copied. */
> - dst_fpu->active_state = &dst_fpu->state;
> -#endif
>
> - if (!IS_ENABLED(CONFIG_IPIPE) &&
> - (!src_fpu->fpstate_active
> || !static_cpu_has(X86_FEATURE_FPU)))
> + if (!src_fpu->fpstate_active
> || !static_cpu_has(X86_FEATURE_FPU)) return 0;
>
> WARN_ON_FPU(src_fpu != ¤t->thread.fpu);
> @@ -283,7 +278,7 @@ int fpu__copy(struct fpu *dst_fpu, struct fpu
> *src_fpu) fpu_kernel_xstate_size);
>
> if (use_eager_fpu())
> -
> copy_kernel_to_fpregs(active_fpstate(src_fpu));
> + copy_kernel_to_fpregs(&src_fpu->state);
> else
> fpregs_deactivate(src_fpu);
> }
> @@ -430,7 +425,7 @@ void fpu__current_fpstate_write_end(void)
> * an XRSTOR if they are active.
> */
> if (fpregs_active())
> - copy_kernel_to_fpregs(active_fpstate(fpu));
> + copy_kernel_to_fpregs(&fpu->state);
>
> /*
> * Our update is done and the fpregs/fpstate are in sync
> @@ -460,7 +455,7 @@ void fpu__restore(struct fpu *fpu)
> kernel_fpu_disable();
> trace_x86_fpu_before_restore(fpu);
> fpregs_activate(fpu);
> - copy_kernel_to_fpregs(active_fpstate(fpu));
> + copy_kernel_to_fpregs(&fpu->state);
> fpu->counter++;
> trace_x86_fpu_after_restore(fpu);
> kernel_fpu_enable();
> diff --git a/arch/x86/kernel/fpu/init.c b/arch/x86/kernel/fpu/init.c
> index 3eee35d3d6f8..a1fc061d03e1 100644
> --- a/arch/x86/kernel/fpu/init.c
> +++ b/arch/x86/kernel/fpu/init.c
> @@ -42,9 +42,6 @@ static void fpu__init_cpu_generic(void)
> cr0 |= X86_CR0_EM;
> write_cr0(cr0);
>
> -#ifdef CONFIG_IPIPE
> - current->thread.fpu.active_state =
> ¤t->thread.fpu.state; -#endif
> /* Flush out any pending x87 state: */
> #ifdef CONFIG_MATH_EMULATION
> if (!boot_cpu_has(X86_FEATURE_FPU))
> @@ -329,7 +326,7 @@ static void __init
> fpu__init_system_ctx_switch(void) eagerfpu = ENABLE;
>
> if (IS_ENABLED(CONFIG_IPIPE))
> - eagerfpu = DISABLE;
> + eagerfpu = ENABLE;
>
> if (eagerfpu == ENABLE)
> setup_force_cpu_cap(X86_FEATURE_EAGER_FPU);
--
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