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Message-ID: <20181003150253.5124e989@roar.ozlabs.ibm.com>
Date: Wed, 3 Oct 2018 15:02:53 +1000
From: Nicholas Piggin <npiggin@...il.com>
To: Christophe Leroy <christophe.leroy@....fr>
Cc: Benjamin Herrenschmidt <benh@...nel.crashing.org>,
Paul Mackerras <paulus@...ba.org>,
Michael Ellerman <mpe@...erman.id.au>,
aneesh.kumar@...ux.vnet.ibm.com, linux-kernel@...r.kernel.org,
linuxppc-dev@...ts.ozlabs.org
Subject: Re: [RFC PATCH v3 2/7] powerpc: Prepare for moving thread_info into
task_struct
On Mon, 1 Oct 2018 12:30:21 +0000 (UTC)
Christophe Leroy <christophe.leroy@....fr> wrote:
> This patch cleans the powerpc kernel before activating
> CONFIG_THREAD_INFO_IN_TASK:
> - The purpose of the pointer given to call_do_softirq() and
> call_do_irq() is to point the new stack ==> change it to void*
> - Don't use CURRENT_THREAD_INFO() to locate the stack.
> - Fixed a few comments.
> - TI_CPU is only used when CONFIG_SMP is set.
> - Replace current_thread_info()->task by current
> - Remove unnecessary casts to thread_info, as they'll become invalid
> once thread_info is not in stack anymore.
> - Ensure task_struct 'cpu' fields is not used directly out of SMP code
> - Rename THREAD_INFO to TASK_STASK: As it is in fact the offset of the
> pointer to the stack in task_struct, this pointer will not be impacted
> by the move of THREAD_INFO.
> - Makes TASK_STACK available to PPC64 which will need it to the get
> stack pointer from current once the thread_info have been moved.
>
> Signed-off-by: Christophe Leroy <christophe.leroy@....fr>
> ---
> arch/powerpc/include/asm/irq.h | 4 ++--
> arch/powerpc/include/asm/livepatch.h | 2 +-
> arch/powerpc/include/asm/processor.h | 4 ++--
> arch/powerpc/include/asm/reg.h | 2 +-
> arch/powerpc/kernel/asm-offsets.c | 2 +-
> arch/powerpc/kernel/entry_32.S | 2 +-
> arch/powerpc/kernel/entry_64.S | 2 +-
> arch/powerpc/kernel/head_32.S | 4 ++--
> arch/powerpc/kernel/head_40x.S | 4 ++--
> arch/powerpc/kernel/head_44x.S | 2 +-
> arch/powerpc/kernel/head_8xx.S | 2 +-
> arch/powerpc/kernel/head_booke.h | 4 ++--
> arch/powerpc/kernel/head_fsl_booke.S | 6 ++++--
> arch/powerpc/kernel/irq.c | 2 +-
> arch/powerpc/kernel/misc_32.S | 8 ++++++--
> arch/powerpc/kernel/process.c | 6 +++---
> arch/powerpc/kernel/setup_32.c | 15 +++++----------
> arch/powerpc/kernel/smp.c | 4 +++-
> arch/powerpc/xmon/xmon.c | 2 +-
> 19 files changed, 40 insertions(+), 37 deletions(-)
>
> diff --git a/arch/powerpc/include/asm/irq.h b/arch/powerpc/include/asm/irq.h
> index ee39ce56b2a2..8108d1fe33ca 100644
> --- a/arch/powerpc/include/asm/irq.h
> +++ b/arch/powerpc/include/asm/irq.h
> @@ -63,8 +63,8 @@ extern struct thread_info *hardirq_ctx[NR_CPUS];
> extern struct thread_info *softirq_ctx[NR_CPUS];
>
> extern void irq_ctx_init(void);
> -extern void call_do_softirq(struct thread_info *tp);
> -extern void call_do_irq(struct pt_regs *regs, struct thread_info *tp);
> +extern void call_do_softirq(void *tp);
> +extern void call_do_irq(struct pt_regs *regs, void *tp);
void *sp for these ?
This all seems okay to me except the 32-bit code which I don't know.
Would it be any trouble for you to put the TI_CPU bits into their own
patch?
Reviewed-by: Nicholas Piggin <npiggin@...il.com>
> 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/include/asm/livepatch.h b/arch/powerpc/include/asm/livepatch.h
> index 47a03b9b528b..818451bf629c 100644
> --- a/arch/powerpc/include/asm/livepatch.h
> +++ b/arch/powerpc/include/asm/livepatch.h
> @@ -49,7 +49,7 @@ static inline void klp_init_thread_info(struct thread_info *ti)
> ti->livepatch_sp = (unsigned long *)(ti + 1) + 1;
> }
> #else
> -static void klp_init_thread_info(struct thread_info *ti) { }
> +static inline void klp_init_thread_info(struct thread_info *ti) { }
> #endif /* CONFIG_LIVEPATCH */
>
> #endif /* _ASM_POWERPC_LIVEPATCH_H */
> diff --git a/arch/powerpc/include/asm/processor.h b/arch/powerpc/include/asm/processor.h
> index 353879db3e98..31873614392f 100644
> --- a/arch/powerpc/include/asm/processor.h
> +++ b/arch/powerpc/include/asm/processor.h
> @@ -40,7 +40,7 @@
>
> #ifndef __ASSEMBLY__
> #include <linux/types.h>
> -#include <asm/thread_info.h>
> +#include <linux/thread_info.h>
> #include <asm/ptrace.h>
> #include <asm/hw_breakpoint.h>
>
> @@ -333,7 +333,7 @@ struct thread_struct {
>
> #define INIT_SP (sizeof(init_stack) + (unsigned long) &init_stack)
> #define INIT_SP_LIMIT \
> - (_ALIGN_UP(sizeof(init_thread_info), 16) + (unsigned long) &init_stack)
> + (_ALIGN_UP(sizeof(struct thread_info), 16) + (unsigned long) &init_stack)
>
> #ifdef CONFIG_SPE
> #define SPEFSCR_INIT \
> diff --git a/arch/powerpc/include/asm/reg.h b/arch/powerpc/include/asm/reg.h
> index e5b314ed054e..f3a9cf19a986 100644
> --- a/arch/powerpc/include/asm/reg.h
> +++ b/arch/powerpc/include/asm/reg.h
> @@ -1053,7 +1053,7 @@
> * - SPRG9 debug exception scratch
> *
> * All 32-bit:
> - * - SPRG3 current thread_info pointer
> + * - SPRG3 current thread_struct physical addr pointer
> * (virtual on BookE, physical on others)
> *
> * 32-bit classic:
> diff --git a/arch/powerpc/kernel/asm-offsets.c b/arch/powerpc/kernel/asm-offsets.c
> index ba9d0fc98730..d1f161e48945 100644
> --- a/arch/powerpc/kernel/asm-offsets.c
> +++ b/arch/powerpc/kernel/asm-offsets.c
> @@ -85,10 +85,10 @@ int main(void)
> DEFINE(NMI_MASK, NMI_MASK);
> OFFSET(TASKTHREADPPR, task_struct, thread.ppr);
> #else
> - OFFSET(THREAD_INFO, task_struct, stack);
> DEFINE(THREAD_INFO_GAP, _ALIGN_UP(sizeof(struct thread_info), 16));
> OFFSET(KSP_LIMIT, thread_struct, ksp_limit);
> #endif /* CONFIG_PPC64 */
> + OFFSET(TASK_STACK, task_struct, stack);
>
> #ifdef CONFIG_LIVEPATCH
> OFFSET(TI_livepatch_sp, thread_info, livepatch_sp);
> diff --git a/arch/powerpc/kernel/entry_32.S b/arch/powerpc/kernel/entry_32.S
> index e58c3f467db5..12c0721f65ea 100644
> --- a/arch/powerpc/kernel/entry_32.S
> +++ b/arch/powerpc/kernel/entry_32.S
> @@ -1166,7 +1166,7 @@ ret_from_debug_exc:
> mfspr r9,SPRN_SPRG_THREAD
> lwz r10,SAVED_KSP_LIMIT(r1)
> stw r10,KSP_LIMIT(r9)
> - lwz r9,THREAD_INFO-THREAD(r9)
> + lwz r9,TASK_STACK-THREAD(r9)
> CURRENT_THREAD_INFO(r10, r1)
> lwz r10,TI_PREEMPT(r10)
> stw r10,TI_PREEMPT(r9)
> diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S
> index 77a888bfcb53..697406572592 100644
> --- a/arch/powerpc/kernel/entry_64.S
> +++ b/arch/powerpc/kernel/entry_64.S
> @@ -680,7 +680,7 @@ END_FTR_SECTION_IFCLR(CPU_FTR_ARCH_207S)
> 2:
> #endif /* CONFIG_PPC_BOOK3S_64 */
>
> - CURRENT_THREAD_INFO(r7, r8) /* base of new stack */
> + clrrdi r7, r8, THREAD_SHIFT /* base of new stack */
> /* Note: this uses SWITCH_FRAME_SIZE rather than INT_FRAME_SIZE
> because we don't need to leave the 288-byte ABI gap at the
> top of the kernel stack. */
> diff --git a/arch/powerpc/kernel/head_32.S b/arch/powerpc/kernel/head_32.S
> index 61ca27929355..dce6f2ff07e5 100644
> --- a/arch/powerpc/kernel/head_32.S
> +++ b/arch/powerpc/kernel/head_32.S
> @@ -261,7 +261,7 @@ __secondary_hold_acknowledge:
> tophys(r11,r1); /* use tophys(r1) if kernel */ \
> beq 1f; \
> mfspr r11,SPRN_SPRG_THREAD; \
> - lwz r11,THREAD_INFO-THREAD(r11); \
> + lwz r11,TASK_STACK-THREAD(r11); \
> addi r11,r11,THREAD_SIZE; \
> tophys(r11,r11); \
> 1: subi r11,r11,INT_FRAME_SIZE /* alloc exc. frame */
> @@ -841,7 +841,7 @@ __secondary_start:
> bl init_idle_6xx
> #endif /* CONFIG_6xx */
>
> - /* get current_thread_info and current */
> + /* get current's stack and current */
> lis r1,secondary_ti@ha
> tophys(r1,r1)
> lwz r1,secondary_ti@l(r1)
> diff --git a/arch/powerpc/kernel/head_40x.S b/arch/powerpc/kernel/head_40x.S
> index b19d78410511..3088c9f29f5e 100644
> --- a/arch/powerpc/kernel/head_40x.S
> +++ b/arch/powerpc/kernel/head_40x.S
> @@ -115,7 +115,7 @@ _ENTRY(saved_ksp_limit)
> andi. r11,r11,MSR_PR; \
> beq 1f; \
> mfspr r1,SPRN_SPRG_THREAD; /* if from user, start at top of */\
> - lwz r1,THREAD_INFO-THREAD(r1); /* this thread's kernel stack */\
> + lwz r1,TASK_STACK-THREAD(r1); /* this thread's kernel stack */\
> addi r1,r1,THREAD_SIZE; \
> 1: subi r1,r1,INT_FRAME_SIZE; /* Allocate an exception frame */\
> tophys(r11,r1); \
> @@ -158,7 +158,7 @@ _ENTRY(saved_ksp_limit)
> beq 1f; \
> /* COMING FROM USER MODE */ \
> mfspr r11,SPRN_SPRG_THREAD; /* if from user, start at top of */\
> - lwz r11,THREAD_INFO-THREAD(r11); /* this thread's kernel stack */\
> + lwz r11,TASK_STACK-THREAD(r11); /* this thread's kernel stack */\
> 1: addi r11,r11,THREAD_SIZE-INT_FRAME_SIZE; /* Alloc an excpt frm */\
> tophys(r11,r11); \
> stw r10,_CCR(r11); /* save various registers */\
> diff --git a/arch/powerpc/kernel/head_44x.S b/arch/powerpc/kernel/head_44x.S
> index 37e4a7cf0065..15d39b2499de 100644
> --- a/arch/powerpc/kernel/head_44x.S
> +++ b/arch/powerpc/kernel/head_44x.S
> @@ -1020,7 +1020,7 @@ _GLOBAL(start_secondary_47x)
>
> /* Now we can get our task struct and real stack pointer */
>
> - /* Get current_thread_info and current */
> + /* Get current's stack and current */
> lis r1,secondary_ti@ha
> lwz r1,secondary_ti@l(r1)
> lwz r2,TI_TASK(r1)
> diff --git a/arch/powerpc/kernel/head_8xx.S b/arch/powerpc/kernel/head_8xx.S
> index 6582f824d620..e56e36aa2b3d 100644
> --- a/arch/powerpc/kernel/head_8xx.S
> +++ b/arch/powerpc/kernel/head_8xx.S
> @@ -124,7 +124,7 @@ turn_on_mmu:
> tophys(r11,r1); /* use tophys(r1) if kernel */ \
> beq 1f; \
> mfspr r11,SPRN_SPRG_THREAD; \
> - lwz r11,THREAD_INFO-THREAD(r11); \
> + lwz r11,TASK_STACK-THREAD(r11); \
> addi r11,r11,THREAD_SIZE; \
> tophys(r11,r11); \
> 1: subi r11,r11,INT_FRAME_SIZE /* alloc exc. frame */
> diff --git a/arch/powerpc/kernel/head_booke.h b/arch/powerpc/kernel/head_booke.h
> index d0862a100d29..20fe0c93a0bd 100644
> --- a/arch/powerpc/kernel/head_booke.h
> +++ b/arch/powerpc/kernel/head_booke.h
> @@ -44,7 +44,7 @@
> mr r11, r1; \
> beq 1f; \
> /* if from user, start at top of this thread's kernel stack */ \
> - lwz r11, THREAD_INFO-THREAD(r10); \
> + lwz r11, TASK_STACK-THREAD(r10); \
> ALLOC_STACK_FRAME(r11, THREAD_SIZE); \
> 1 : subi r11, r11, INT_FRAME_SIZE; /* Allocate exception frame */ \
> stw r13, _CCR(r11); /* save various registers */ \
> @@ -130,7 +130,7 @@
> DO_KVM BOOKE_INTERRUPT_##intno exc_level_srr1; \
> andi. r11,r11,MSR_PR; \
> mfspr r11,SPRN_SPRG_THREAD; /* if from user, start at top of */\
> - lwz r11,THREAD_INFO-THREAD(r11); /* this thread's kernel stack */\
> + lwz r11,TASK_STACK-THREAD(r11); /* this thread's kernel stack */\
> addi r11,r11,EXC_LVL_FRAME_OVERHEAD; /* allocate stack frame */\
> beq 1f; \
> /* COMING FROM USER MODE */ \
> diff --git a/arch/powerpc/kernel/head_fsl_booke.S b/arch/powerpc/kernel/head_fsl_booke.S
> index e2750b856c8f..239ad8a4754e 100644
> --- a/arch/powerpc/kernel/head_fsl_booke.S
> +++ b/arch/powerpc/kernel/head_fsl_booke.S
> @@ -243,8 +243,10 @@ set_ivor:
> li r0,0
> stwu r0,THREAD_SIZE-STACK_FRAME_OVERHEAD(r1)
>
> +#ifdef CONFIG_SMP
> CURRENT_THREAD_INFO(r22, r1)
> stw r24, TI_CPU(r22)
> +#endif
>
> bl early_init
>
> @@ -702,7 +704,7 @@ finish_tlb_load:
>
> /* Get the next_tlbcam_idx percpu var */
> #ifdef CONFIG_SMP
> - lwz r12, THREAD_INFO-THREAD(r12)
> + lwz r12, TASK_STACK-THREAD(r12)
> lwz r15, TI_CPU(r12)
> lis r14, __per_cpu_offset@h
> ori r14, r14, __per_cpu_offset@l
> @@ -1074,7 +1076,7 @@ __secondary_start:
> mr r4,r24 /* Why? */
> bl call_setup_cpu
>
> - /* get current_thread_info and current */
> + /* get current's stack and current */
> lis r1,secondary_ti@ha
> lwz r1,secondary_ti@l(r1)
> lwz r2,TI_TASK(r1)
> diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c
> index 916ddc4aac44..aa53db3ba6e7 100644
> --- a/arch/powerpc/kernel/irq.c
> +++ b/arch/powerpc/kernel/irq.c
> @@ -663,7 +663,7 @@ void do_IRQ(struct pt_regs *regs)
> struct thread_info *curtp, *irqtp, *sirqtp;
>
> /* Switch to the irq stack to handle this */
> - curtp = current_thread_info();
> + curtp = (void*)(current_stack_pointer() & ~(THREAD_SIZE - 1));
> irqtp = hardirq_ctx[raw_smp_processor_id()];
> sirqtp = softirq_ctx[raw_smp_processor_id()];
>
> diff --git a/arch/powerpc/kernel/misc_32.S b/arch/powerpc/kernel/misc_32.S
> index 695b24a2d954..24a7f18ea10c 100644
> --- a/arch/powerpc/kernel/misc_32.S
> +++ b/arch/powerpc/kernel/misc_32.S
> @@ -60,7 +60,7 @@ _GLOBAL(call_do_softirq)
> blr
>
> /*
> - * void call_do_irq(struct pt_regs *regs, struct thread_info *irqtp);
> + * void call_do_irq(struct pt_regs *regs, void *irqtp);
> */
> _GLOBAL(call_do_irq)
> mflr r0
> @@ -183,10 +183,14 @@ _GLOBAL(low_choose_750fx_pll)
> or r4,r4,r5
> mtspr SPRN_HID1,r4
>
> +#ifdef CONFIG_SMP
> /* Store new HID1 image */
> CURRENT_THREAD_INFO(r6, r1)
> lwz r6,TI_CPU(r6)
> slwi r6,r6,2
> +#else
> + li r6, 0
> +#endif
> addis r6,r6,nap_save_hid1@ha
> stw r4,nap_save_hid1@l(r6)
>
> @@ -599,7 +603,7 @@ EXPORT_SYMBOL(__bswapdi2)
> #ifdef CONFIG_SMP
> _GLOBAL(start_secondary_resume)
> /* Reset stack */
> - CURRENT_THREAD_INFO(r1, r1)
> + rlwinm r1, r1, 0, 0, 31 - THREAD_SHIFT
> addi r1,r1,THREAD_SIZE-STACK_FRAME_OVERHEAD
> li r3,0
> stw r3,0(r1) /* Zero the stack frame pointer */
> diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
> index 03c2e1f134bc..111abb4df2ec 100644
> --- a/arch/powerpc/kernel/process.c
> +++ b/arch/powerpc/kernel/process.c
> @@ -1240,8 +1240,8 @@ struct task_struct *__switch_to(struct task_struct *prev,
> batch->active = 1;
> }
>
> - if (current_thread_info()->task->thread.regs) {
> - restore_math(current_thread_info()->task->thread.regs);
> + if (current->thread.regs) {
> + restore_math(current->thread.regs);
>
> /*
> * The copy-paste buffer can only store into foreign real
> @@ -1251,7 +1251,7 @@ struct task_struct *__switch_to(struct task_struct *prev,
> * mappings, we must issue a cp_abort to clear any state and
> * prevent snooping, corruption or a covert channel.
> */
> - if (current_thread_info()->task->thread.used_vas)
> + if (current->thread.used_vas)
> asm volatile(PPC_CP_ABORT);
> }
> #endif /* CONFIG_PPC_BOOK3S_64 */
> diff --git a/arch/powerpc/kernel/setup_32.c b/arch/powerpc/kernel/setup_32.c
> index 8c507be12c3c..81ebf7d6f526 100644
> --- a/arch/powerpc/kernel/setup_32.c
> +++ b/arch/powerpc/kernel/setup_32.c
> @@ -205,10 +205,8 @@ void __init irqstack_early_init(void)
> /* interrupt stacks must be in lowmem, we get that for free on ppc32
> * as the memblock is limited to lowmem by default */
> for_each_possible_cpu(i) {
> - softirq_ctx[i] = (struct thread_info *)
> - __va(memblock_alloc(THREAD_SIZE, THREAD_SIZE));
> - hardirq_ctx[i] = (struct thread_info *)
> - __va(memblock_alloc(THREAD_SIZE, THREAD_SIZE));
> + softirq_ctx[i] = __va(memblock_alloc(THREAD_SIZE, THREAD_SIZE));
> + hardirq_ctx[i] = __va(memblock_alloc(THREAD_SIZE, THREAD_SIZE));
> }
> }
>
> @@ -226,13 +224,10 @@ void __init exc_lvl_early_init(void)
> hw_cpu = 0;
> #endif
>
> - critirq_ctx[hw_cpu] = (struct thread_info *)
> - __va(memblock_alloc(THREAD_SIZE, THREAD_SIZE));
> + critirq_ctx[hw_cpu] = __va(memblock_alloc(THREAD_SIZE, THREAD_SIZE));
> #ifdef CONFIG_BOOKE
> - dbgirq_ctx[hw_cpu] = (struct thread_info *)
> - __va(memblock_alloc(THREAD_SIZE, THREAD_SIZE));
> - mcheckirq_ctx[hw_cpu] = (struct thread_info *)
> - __va(memblock_alloc(THREAD_SIZE, THREAD_SIZE));
> + dbgirq_ctx[hw_cpu] = __va(memblock_alloc(THREAD_SIZE, THREAD_SIZE));
> + mcheckirq_ctx[hw_cpu] = __va(memblock_alloc(THREAD_SIZE, THREAD_SIZE));
> #endif
> }
> }
> diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
> index 61c1fadbc644..19dd0ea55714 100644
> --- a/arch/powerpc/kernel/smp.c
> +++ b/arch/powerpc/kernel/smp.c
> @@ -20,6 +20,7 @@
> #include <linux/kernel.h>
> #include <linux/export.h>
> #include <linux/sched/mm.h>
> +#include <linux/sched/task_stack.h>
> #include <linux/sched/topology.h>
> #include <linux/smp.h>
> #include <linux/interrupt.h>
> @@ -812,7 +813,8 @@ static void cpu_idle_thread_init(unsigned int cpu, struct task_struct *idle)
>
> #ifdef CONFIG_PPC64
> paca_ptrs[cpu]->__current = idle;
> - paca_ptrs[cpu]->kstack = (unsigned long)ti + THREAD_SIZE - STACK_FRAME_OVERHEAD;
> + paca_ptrs[cpu]->kstack = (unsigned long)task_stack_page(idle) +
> + THREAD_SIZE - STACK_FRAME_OVERHEAD;
> #endif
> ti->cpu = cpu;
> secondary_ti = current_set[cpu] = ti;
> diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c
> index 694c1d92e796..0d8d6fee892a 100644
> --- a/arch/powerpc/xmon/xmon.c
> +++ b/arch/powerpc/xmon/xmon.c
> @@ -2988,7 +2988,7 @@ static void show_task(struct task_struct *tsk)
> printf("%px %016lx %6d %6d %c %2d %s\n", tsk,
> tsk->thread.ksp,
> tsk->pid, tsk->parent->pid,
> - state, task_thread_info(tsk)->cpu,
> + state, task_cpu(tsk),
> tsk->comm);
> }
>
> --
> 2.13.3
>
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