Messages in this thread | | | Subject | Re: [PATCH v5] powerpc/irq: inline call_do_irq() and call_do_softirq() on PPC32 | From | Christophe Leroy <> | Date | Mon, 1 Jun 2020 09:26:00 +0200 |
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Hi Michael,
Le 07/12/2019 à 18:20, Christophe Leroy a écrit : > call_do_irq() and call_do_softirq() are simple enough to be > worth inlining. > > Inlining them avoids an mflr/mtlr pair plus a save/reload on stack. > It also allows GCC to keep the saved ksp_limit in an nonvolatile reg. > > This is inspired from S390 arch. Several other arches do more or > less the same. The way sparc arch does seems odd thought. > > Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> > Reviewed-by: Segher Boessenkool <segher@kernel.crashing.org>
Anything more I need to do for this patch to get merged ?
Thanks Christophe
> > --- > v2: no change. > v3: no change. > v4: > - comment reminding the purpose of the inline asm block. > - added r2 as clobbered reg > v5: > - Limiting the change to PPC32 for now. > - removed r2 from the clobbered regs list (on PPC32 r2 points to current all the time) > - Removed patch 1 and merged ksp_limit handling in here. > --- > arch/powerpc/include/asm/irq.h | 2 ++ > arch/powerpc/kernel/irq.c | 48 ++++++++++++++++++++++++++++++++++++++++++ > arch/powerpc/kernel/misc_32.S | 39 ---------------------------------- > 3 files changed, 50 insertions(+), 39 deletions(-) > > diff --git a/arch/powerpc/include/asm/irq.h b/arch/powerpc/include/asm/irq.h > index 814dfab7e392..e4a92f0b4ad4 100644 > --- a/arch/powerpc/include/asm/irq.h > +++ b/arch/powerpc/include/asm/irq.h > @@ -56,8 +56,10 @@ extern void *mcheckirq_ctx[NR_CPUS]; > extern void *hardirq_ctx[NR_CPUS]; > extern void *softirq_ctx[NR_CPUS]; > > +#ifdef CONFIG_PPC64 > void call_do_softirq(void *sp); > void call_do_irq(struct pt_regs *regs, void *sp); > +#endif > extern void do_IRQ(struct pt_regs *regs); > extern void __init init_IRQ(void); > extern void __do_irq(struct pt_regs *regs); > diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c > index 5645bc9cbc09..240eca12c71d 100644 > --- a/arch/powerpc/kernel/irq.c > +++ b/arch/powerpc/kernel/irq.c > @@ -611,6 +611,54 @@ static inline void check_stack_overflow(void) > #endif > } > > +#ifdef CONFIG_PPC32 > +static inline void call_do_softirq(const void *sp) > +{ > + register unsigned long ret asm("r3"); > + unsigned long limit = current->thread.ksp_limit; > + > + /* Adjust the stack limit */ > + current->thread.ksp_limit = (unsigned long)sp; > + > + /* Temporarily switch r1 to sp, call __do_softirq() then restore r1. */ > + asm volatile( > + " "PPC_STLU" 1, %2(%1);\n" > + " mr 1, %1;\n" > + " bl %3;\n" > + " "PPC_LL" 1, 0(1);\n" : > + "=r"(ret) : > + "b"(sp), "i"(THREAD_SIZE - STACK_FRAME_OVERHEAD), "i"(__do_softirq) : > + "lr", "xer", "ctr", "memory", "cr0", "cr1", "cr5", "cr6", "cr7", > + "r0", "r4", "r5", "r6", "r7", "r8", "r9", "r10", "r11", "r12"); > + > + /* Restore stack limit */ > + current->thread.ksp_limit = limit; > +} > + > +static inline void call_do_irq(struct pt_regs *regs, void *sp) > +{ > + register unsigned long r3 asm("r3") = (unsigned long)regs; > + unsigned long limit = current->thread.ksp_limit; > + > + /* Adjust the stack limit */ > + current->thread.ksp_limit = (unsigned long)sp; > + > + /* Temporarily switch r1 to sp, call __do_irq() then restore r1 */ > + asm volatile( > + " "PPC_STLU" 1, %2(%1);\n" > + " mr 1, %1;\n" > + " bl %3;\n" > + " "PPC_LL" 1, 0(1);\n" : > + "+r"(r3) : > + "b"(sp), "i"(THREAD_SIZE - STACK_FRAME_OVERHEAD), "i"(__do_irq) : > + "lr", "xer", "ctr", "memory", "cr0", "cr1", "cr5", "cr6", "cr7", > + "r0", "r4", "r5", "r6", "r7", "r8", "r9", "r10", "r11", "r12"); > + > + /* Restore stack limit */ > + current->thread.ksp_limit = limit; > +} > +#endif > + > void __do_irq(struct pt_regs *regs) > { > unsigned int irq; > diff --git a/arch/powerpc/kernel/misc_32.S b/arch/powerpc/kernel/misc_32.S > index d80212be8698..341a3cd199cb 100644 > --- a/arch/powerpc/kernel/misc_32.S > +++ b/arch/powerpc/kernel/misc_32.S > @@ -28,45 +28,6 @@ > .text > > /* > - * We store the saved ksp_limit in the unused part > - * of the STACK_FRAME_OVERHEAD > - */ > -_GLOBAL(call_do_softirq) > - mflr r0 > - stw r0,4(r1) > - lwz r10,THREAD+KSP_LIMIT(r2) > - stw r3, THREAD+KSP_LIMIT(r2) > - stwu r1,THREAD_SIZE-STACK_FRAME_OVERHEAD(r3) > - mr r1,r3 > - stw r10,8(r1) > - bl __do_softirq > - lwz r10,8(r1) > - lwz r1,0(r1) > - lwz r0,4(r1) > - stw r10,THREAD+KSP_LIMIT(r2) > - mtlr r0 > - blr > - > -/* > - * void call_do_irq(struct pt_regs *regs, void *sp); > - */ > -_GLOBAL(call_do_irq) > - mflr r0 > - stw r0,4(r1) > - lwz r10,THREAD+KSP_LIMIT(r2) > - stw r4, THREAD+KSP_LIMIT(r2) > - stwu r1,THREAD_SIZE-STACK_FRAME_OVERHEAD(r4) > - mr r1,r4 > - stw r10,8(r1) > - bl __do_irq > - lwz r10,8(r1) > - lwz r1,0(r1) > - lwz r0,4(r1) > - stw r10,THREAD+KSP_LIMIT(r2) > - mtlr r0 > - blr > - > -/* > * This returns the high 64 bits of the product of two 64-bit numbers. > */ > _GLOBAL(mulhdu) >
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