On Fri, 2021-03-12 at 11:20 +1000, Nicholas Piggin wrote:
>
> +static inline void nap_adjust_return(struct pt_regs *regs)
>
> +{
>
> +#ifdef CONFIG_PPC_970_NAP
>
> + if (unlikely(test_thread_local_flags(_TLF_NAPPING))) {
> + /* Can avoid a test-and-clear because NMIs do not call this */
> + clear_thread_local_flags(_TLF_NAPPING);
> + regs->nip = (unsigned long)power4_idle_nap_return;
> + }
Is this a pointer to a function descriptor or the actual code ?
Cheers,
Ben.
> +#endif
>
> +}
>
> +
>
> struct interrupt_state {
>
> #ifdef CONFIG_PPC_BOOK3E_64
>
> enum ctx_state ctx_state;
>
> @@ -111,6 +122,9 @@ static inline void interrupt_async_exit_prepare(struct
> pt_regs *regs, struct int
>
> {
>
> irq_exit();
>
> interrupt_exit_prepare(regs, state);
>
> +
>
> + /* Adjust at exit so the main handler sees the true NIA */
>
> + nap_adjust_return(regs);
>
> }
>
>
>
> struct interrupt_nmi_state {
>
> @@ -164,6 +178,11 @@ static inline void interrupt_nmi_exit_prepare(struct
> pt_regs *regs, struct inter
>
> radix_enabled() || (mfmsr() & MSR_DR))
>
> nmi_exit();
>
>
>
> + /*
>
> + * nmi does not call nap_adjust_return because nmi should not create
>
> + * new work to do (must use irq_work for that).
>
> + */
>
> +
>
> #ifdef CONFIG_PPC64
>
> if (TRAP(regs) != 0x900 && TRAP(regs) != 0xf00 && TRAP(regs) != 0x260)
>
> this_cpu_set_ftrace_enabled(state->ftrace_enabled);
>
> diff --git a/arch/powerpc/include/asm/processor.h
> b/arch/powerpc/include/asm/processor.h
>
> index 8acc3590c971..eedc3c775141 100644
>
> --- a/arch/powerpc/include/asm/processor.h
>
> +++ b/arch/powerpc/include/asm/processor.h
>
> @@ -393,6 +393,7 @@ extern unsigned long isa300_idle_stop_mayloss(unsigned
> long psscr_val);
>
> extern unsigned long isa206_idle_insn_mayloss(unsigned long type);
>
> #ifdef CONFIG_PPC_970_NAP
>
> extern void power4_idle_nap(void);
>
> +void power4_idle_nap_return(void);
>
> #endif
>
>
>
> extern unsigned long cpuidle_disable;
>
> diff --git a/arch/powerpc/include/asm/thread_info.h
> b/arch/powerpc/include/asm/thread_info.h
>
> index 386d576673a1..bf137151100b 100644
>
> --- a/arch/powerpc/include/asm/thread_info.h
>
> +++ b/arch/powerpc/include/asm/thread_info.h
>
> @@ -152,6 +152,12 @@ void arch_setup_new_exec(void);
>
>
>
> #ifndef __ASSEMBLY__
>
>
>
> +static inline void clear_thread_local_flags(unsigned int flags)
>
> +{
>
> + struct thread_info *ti = current_thread_info();
>
> + ti->local_flags &= ~flags;
>
> +}
>
> +
>
> static inline bool test_thread_local_flags(unsigned int flags)
>
> {
>
> struct thread_info *ti = current_thread_info();
>
> diff --git a/arch/powerpc/kernel/exceptions-64s.S
> b/arch/powerpc/kernel/exceptions-64s.S
>
> index 60d3051a8bc8..ea7a443488d2 100644
>
> --- a/arch/powerpc/kernel/exceptions-64s.S
>
> +++ b/arch/powerpc/kernel/exceptions-64s.S
>
> @@ -692,25 +692,6 @@ END_FTR_SECTION_IFSET(CPU_FTR_CFAR)
>
> ld r1,GPR1(r1)
>
> .endm
>
>
>
> -/*
>
> - * When the idle code in power4_idle puts the CPU into NAP mode,
>
> - * it has to do so in a loop, and relies on the external interrupt
>
> - * and decrementer interrupt entry code to get it out of the loop.
>
> - * It sets the _TLF_NAPPING bit in current_thread_info()->local_flags
>
> - * to signal that it is in the loop and needs help to get out.
>
> - */
>
> -#ifdef CONFIG_PPC_970_NAP
>
> -#define FINISH_NAP \
>
> -BEGIN_FTR_SECTION \
>
> - ld r11, PACA_THREAD_INFO(r13); \
>
> - ld r9,TI_LOCAL_FLAGS(r11); \
>
> - andi. r10,r9,_TLF_NAPPING; \
>
> - bnel power4_fixup_nap; \
>
> -END_FTR_SECTION_IFSET(CPU_FTR_CAN_NAP)
>
> -#else
>
> -#define FINISH_NAP
>
> -#endif
>
> -
>
> /*
>
> * There are a few constraints to be concerned with.
>
> * - Real mode exceptions code/data must be located at their physical
> location.
>
> @@ -1248,7 +1229,6 @@ EXC_COMMON_BEGIN(machine_check_common)
>
> */
>
> GEN_COMMON machine_check
>
>
>
> - FINISH_NAP
>
> /* Enable MSR_RI when finished with PACA_EXMC */
>
> li r10,MSR_RI
>
> mtmsrd r10,1
>
> @@ -1571,7 +1551,6 @@ EXC_VIRT_BEGIN(hardware_interrupt, 0x4500, 0x100)
>
> EXC_VIRT_END(hardware_interrupt, 0x4500, 0x100)
>
> EXC_COMMON_BEGIN(hardware_interrupt_common)
>
> GEN_COMMON hardware_interrupt
>
> - FINISH_NAP
>
> addi r3,r1,STACK_FRAME_OVERHEAD
>
> bl do_IRQ
>
> b interrupt_return
>
> @@ -1801,7 +1780,6 @@ EXC_VIRT_BEGIN(decrementer, 0x4900, 0x80)
>
> EXC_VIRT_END(decrementer, 0x4900, 0x80)
>
> EXC_COMMON_BEGIN(decrementer_common)
>
> GEN_COMMON decrementer
>
> - FINISH_NAP
>
> addi r3,r1,STACK_FRAME_OVERHEAD
>
> bl timer_interrupt
>
> b interrupt_return
>
> @@ -1886,7 +1864,6 @@ EXC_VIRT_BEGIN(doorbell_super, 0x4a00, 0x100)
>
> EXC_VIRT_END(doorbell_super, 0x4a00, 0x100)
>
> EXC_COMMON_BEGIN(doorbell_super_common)
>
> GEN_COMMON doorbell_super
>
> - FINISH_NAP
>
> addi r3,r1,STACK_FRAME_OVERHEAD
>
> #ifdef CONFIG_PPC_DOORBELL
>
> bl doorbell_exception
>
> @@ -2237,7 +2214,6 @@ EXC_COMMON_BEGIN(hmi_exception_early_common)
>
>
>
> EXC_COMMON_BEGIN(hmi_exception_common)
>
> GEN_COMMON hmi_exception
>
> - FINISH_NAP
>
> addi r3,r1,STACK_FRAME_OVERHEAD
>
> bl handle_hmi_exception
>
> b interrupt_return
>
> @@ -2266,7 +2242,6 @@ EXC_VIRT_BEGIN(h_doorbell, 0x4e80, 0x20)
>
> EXC_VIRT_END(h_doorbell, 0x4e80, 0x20)
>
> EXC_COMMON_BEGIN(h_doorbell_common)
>
> GEN_COMMON h_doorbell
>
> - FINISH_NAP
>
> addi r3,r1,STACK_FRAME_OVERHEAD
>
> #ifdef CONFIG_PPC_DOORBELL
>
> bl doorbell_exception
>
> @@ -2299,7 +2274,6 @@ EXC_VIRT_BEGIN(h_virt_irq, 0x4ea0, 0x20)
>
> EXC_VIRT_END(h_virt_irq, 0x4ea0, 0x20)
>
> EXC_COMMON_BEGIN(h_virt_irq_common)
>
> GEN_COMMON h_virt_irq
>
> - FINISH_NAP
>
> addi r3,r1,STACK_FRAME_OVERHEAD
>
> bl do_IRQ
>
> b interrupt_return
>
> @@ -2345,7 +2319,6 @@ EXC_VIRT_BEGIN(performance_monitor, 0x4f00, 0x20)
>
> EXC_VIRT_END(performance_monitor, 0x4f00, 0x20)
>
> EXC_COMMON_BEGIN(performance_monitor_common)
>
> GEN_COMMON performance_monitor
>
> - FINISH_NAP
>
> addi r3,r1,STACK_FRAME_OVERHEAD
>
> bl performance_monitor_exception
>
> b interrupt_return
>
> @@ -3096,24 +3069,6 @@ USE_FIXED_SECTION(virt_trampolines)
>
> __end_interrupts:
>
> DEFINE_FIXED_SYMBOL(__end_interrupts)
>
>
>
> -#ifdef CONFIG_PPC_970_NAP
>
> - /*
>
> - * Called by exception entry code if _TLF_NAPPING was set, this clears
>
> - * the NAPPING flag, and redirects the exception exit to
>
> - * power4_fixup_nap_return.
>
> - */
>
> - .globl power4_fixup_nap
>
> -EXC_COMMON_BEGIN(power4_fixup_nap)
>
> - andc r9,r9,r10
>
> - std r9,TI_LOCAL_FLAGS(r11)
>
> - LOAD_REG_ADDR(r10, power4_idle_nap_return)
>
> - std r10,_NIP(r1)
>
> - blr
>
> -
>
> -power4_idle_nap_return:
>
> - blr
>
> -#endif
>
> -
>
> CLOSE_FIXED_SECTION(real_vectors);
>
> CLOSE_FIXED_SECTION(real_trampolines);
>
> CLOSE_FIXED_SECTION(virt_vectors);
>
> diff --git a/arch/powerpc/kernel/idle_book3s.S
> b/arch/powerpc/kernel/idle_book3s.S
>
> index f9e6d83e6720..abb719b21cae 100644
>
> --- a/arch/powerpc/kernel/idle_book3s.S
>
> +++ b/arch/powerpc/kernel/idle_book3s.S
>
> @@ -209,4 +209,8 @@ _GLOBAL(power4_idle_nap)
>
> mtmsrd r7
>
> isync
>
> b 1b
>
> +
>
> + .globl power4_idle_nap_return
>
> +power4_idle_nap_return:
>
> + blr
>
> #endif
>
> --
>
> 2.23.0
