[PATCH] powerpc/32: Fix critical and debug interrupts on BOOKE
Christophe Leroy
christophe.leroy at csgroup.eu
Wed Aug 4 15:52:43 AEST 2021
Hi Radu,
Le 07/07/2021 à 07:55, Christophe Leroy a écrit :
> 32 bits BOOKE have special interrupts for debug and other
> critical events.
Were you able to test this patch ?
Thanks
Christophe
>
> When handling those interrupts, dedicated registers are saved
> in the stack frame in addition to the standard registers, leading
> to a shift of the pt_regs struct.
>
> Since commit db297c3b07af ("powerpc/32: Don't save thread.regs on
> interrupt entry"), the pt_regs struct is expected to be at the
> same place all the time.
>
> Instead of handling a special struct in addition to pt_regs, just
> add those special registers to struct pt_regs.
>
> Reported-by: Radu Rendec <radu.rendec at gmail.com>
> Signed-off-by: Christophe Leroy <christophe.leroy at csgroup.eu>
> Fixes: db297c3b07af ("powerpc/32: Don't save thread.regs on interrupt entry")
> Cc: stable at vger.kernel.org
> ---
> arch/powerpc/include/asm/ptrace.h | 16 ++++++++++++++++
> arch/powerpc/kernel/asm-offsets.c | 31 ++++++++++++++-----------------
> arch/powerpc/kernel/head_booke.h | 27 +++------------------------
> 3 files changed, 33 insertions(+), 41 deletions(-)
>
> diff --git a/arch/powerpc/include/asm/ptrace.h b/arch/powerpc/include/asm/ptrace.h
> index 3e5d470a6155..14422e851494 100644
> --- a/arch/powerpc/include/asm/ptrace.h
> +++ b/arch/powerpc/include/asm/ptrace.h
> @@ -70,6 +70,22 @@ struct pt_regs
> unsigned long __pad[4]; /* Maintain 16 byte interrupt stack alignment */
> };
> #endif
> +#if defined(CONFIG_PPC32) && defined(CONFIG_BOOKE)
> + struct { /* Must be a multiple of 16 bytes */
> + unsigned long mas0;
> + unsigned long mas1;
> + unsigned long mas2;
> + unsigned long mas3;
> + unsigned long mas6;
> + unsigned long mas7;
> + unsigned long srr0;
> + unsigned long srr1;
> + unsigned long csrr0;
> + unsigned long csrr1;
> + unsigned long dsrr0;
> + unsigned long dsrr1;
> + };
> +#endif
> };
> #endif
>
> diff --git a/arch/powerpc/kernel/asm-offsets.c b/arch/powerpc/kernel/asm-offsets.c
> index a47eefa09bcb..5bee245d832b 100644
> --- a/arch/powerpc/kernel/asm-offsets.c
> +++ b/arch/powerpc/kernel/asm-offsets.c
> @@ -309,24 +309,21 @@ int main(void)
> STACK_PT_REGS_OFFSET(STACK_REGS_IAMR, iamr);
> #endif
>
> -#if defined(CONFIG_PPC32)
> -#if defined(CONFIG_BOOKE) || defined(CONFIG_40x)
> - DEFINE(EXC_LVL_SIZE, STACK_EXC_LVL_FRAME_SIZE);
> - DEFINE(MAS0, STACK_INT_FRAME_SIZE+offsetof(struct exception_regs, mas0));
> +#if defined(CONFIG_PPC32) && defined(CONFIG_BOOKE)
> + STACK_PT_REGS_OFFSET(MAS0, mas0);
> /* we overload MMUCR for 44x on MAS0 since they are mutually exclusive */
> - DEFINE(MMUCR, STACK_INT_FRAME_SIZE+offsetof(struct exception_regs, mas0));
> - DEFINE(MAS1, STACK_INT_FRAME_SIZE+offsetof(struct exception_regs, mas1));
> - DEFINE(MAS2, STACK_INT_FRAME_SIZE+offsetof(struct exception_regs, mas2));
> - DEFINE(MAS3, STACK_INT_FRAME_SIZE+offsetof(struct exception_regs, mas3));
> - DEFINE(MAS6, STACK_INT_FRAME_SIZE+offsetof(struct exception_regs, mas6));
> - DEFINE(MAS7, STACK_INT_FRAME_SIZE+offsetof(struct exception_regs, mas7));
> - DEFINE(_SRR0, STACK_INT_FRAME_SIZE+offsetof(struct exception_regs, srr0));
> - DEFINE(_SRR1, STACK_INT_FRAME_SIZE+offsetof(struct exception_regs, srr1));
> - DEFINE(_CSRR0, STACK_INT_FRAME_SIZE+offsetof(struct exception_regs, csrr0));
> - DEFINE(_CSRR1, STACK_INT_FRAME_SIZE+offsetof(struct exception_regs, csrr1));
> - DEFINE(_DSRR0, STACK_INT_FRAME_SIZE+offsetof(struct exception_regs, dsrr0));
> - DEFINE(_DSRR1, STACK_INT_FRAME_SIZE+offsetof(struct exception_regs, dsrr1));
> -#endif
> + STACK_PT_REGS_OFFSET(MMUCR, mas0);
> + STACK_PT_REGS_OFFSET(MAS1, mas1);
> + STACK_PT_REGS_OFFSET(MAS2, mas2);
> + STACK_PT_REGS_OFFSET(MAS3, mas3);
> + STACK_PT_REGS_OFFSET(MAS6, mas6);
> + STACK_PT_REGS_OFFSET(MAS7, mas7);
> + STACK_PT_REGS_OFFSET(_SRR0, srr0);
> + STACK_PT_REGS_OFFSET(_SRR1, srr1);
> + STACK_PT_REGS_OFFSET(_CSRR0, csrr0);
> + STACK_PT_REGS_OFFSET(_CSRR1, csrr1);
> + STACK_PT_REGS_OFFSET(_DSRR0, dsrr0);
> + STACK_PT_REGS_OFFSET(_DSRR1, dsrr1);
> #endif
>
> /* About the CPU features table */
> diff --git a/arch/powerpc/kernel/head_booke.h b/arch/powerpc/kernel/head_booke.h
> index 87b806e8eded..e5503420b6c6 100644
> --- a/arch/powerpc/kernel/head_booke.h
> +++ b/arch/powerpc/kernel/head_booke.h
> @@ -168,20 +168,18 @@ ALT_FTR_SECTION_END_IFSET(CPU_FTR_EMB_HV)
> /* only on e500mc */
> #define DBG_STACK_BASE dbgirq_ctx
>
> -#define EXC_LVL_FRAME_OVERHEAD (THREAD_SIZE - INT_FRAME_SIZE - EXC_LVL_SIZE)
> -
> #ifdef CONFIG_SMP
> #define BOOKE_LOAD_EXC_LEVEL_STACK(level) \
> mfspr r8,SPRN_PIR; \
> slwi r8,r8,2; \
> addis r8,r8,level##_STACK_BASE at ha; \
> lwz r8,level##_STACK_BASE at l(r8); \
> - addi r8,r8,EXC_LVL_FRAME_OVERHEAD;
> + addi r8,r8,THREAD_SIZE - INT_FRAME_SIZE;
> #else
> #define BOOKE_LOAD_EXC_LEVEL_STACK(level) \
> lis r8,level##_STACK_BASE at ha; \
> lwz r8,level##_STACK_BASE at l(r8); \
> - addi r8,r8,EXC_LVL_FRAME_OVERHEAD;
> + addi r8,r8,THREAD_SIZE - INT_FRAME_SIZE;
> #endif
>
> /*
> @@ -208,7 +206,7 @@ ALT_FTR_SECTION_END_IFSET(CPU_FTR_EMB_HV)
> mtmsr r11; \
> mfspr r11,SPRN_SPRG_THREAD; /* if from user, start at top of */\
> lwz r11, TASK_STACK - THREAD(r11); /* this thread's kernel stack */\
> - addi r11,r11,EXC_LVL_FRAME_OVERHEAD; /* allocate stack frame */\
> + addi r11,r11,THREAD_SIZE - INT_FRAME_SIZE; /* allocate stack frame */\
> beq 1f; \
> /* COMING FROM USER MODE */ \
> stw r9,_CCR(r11); /* save CR */\
> @@ -516,24 +514,5 @@ ALT_FTR_SECTION_END_IFSET(CPU_FTR_EMB_HV)
> bl kernel_fp_unavailable_exception; \
> b interrupt_return
>
> -#else /* __ASSEMBLY__ */
> -struct exception_regs {
> - unsigned long mas0;
> - unsigned long mas1;
> - unsigned long mas2;
> - unsigned long mas3;
> - unsigned long mas6;
> - unsigned long mas7;
> - unsigned long srr0;
> - unsigned long srr1;
> - unsigned long csrr0;
> - unsigned long csrr1;
> - unsigned long dsrr0;
> - unsigned long dsrr1;
> -};
> -
> -/* ensure this structure is always sized to a multiple of the stack alignment */
> -#define STACK_EXC_LVL_FRAME_SIZE ALIGN(sizeof (struct exception_regs), 16)
> -
> #endif /* __ASSEMBLY__ */
> #endif /* __HEAD_BOOKE_H__ */
>
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