Re: [Crash-utility] [PATCH v2 4/6] ppc64: handle backtrace when CPU is in an emerency stack

On 2022/07/04 14:25, Hari Bathini wrote: > A CPU could be in an emergency stack when it is running in real mode > or any special scenario like TM bad thing. Also, there are dedicated > emergency stacks for machine check and system reset interrupt. Right > now, no backtrace is provided if a CPU is in any of these stacks. > This change ensures backtrace is processed appropriately even when > a CPU is in any one of these emergency stacks. Also, if stack info > cannot be found, print that message always instead of only when > verbose logs are enabled. > > Signed-off-by: Hari Bathini <hbathini(a)linux.ibm.com&gt; > --- > > Changes in v2: > * Avoid using variable length array for paca_ptrs. > > > defs.h | 12 ++++ > ppc64.c | 203 ++++++++++++++++++++++++++++++++++++++++++++++++++++---- > 2 files changed, 203 insertions(+), 12 deletions(-) > > diff --git a/defs.h b/defs.h > index d1d3ea9..9b1b69a 100644 > --- a/defs.h > +++ b/defs.h > @@ -6288,6 +6288,13 @@ struct ppc64_elf_prstatus { > > #ifdef PPC64 > > +enum emergency_stack_type { > + NONE_STACK = 0, > + EMERGENCY_STACK, > + NMI_EMERGENCY_STACK, > + MC_EMERGENCY_STACK > +}; > + > struct ppc64_opal { > uint64_t base; > uint64_t entry; > @@ -6307,6 +6314,11 @@ struct machine_specific { > char *hwstackbuf; > uint hwstacksize; > > + /* Emergency stacks */ > + ulong *emergency_sp; > + ulong *nmi_emergency_sp; > + ulong *mc_emergency_sp; > + > uint l4_index_size; > uint l3_index_size; > uint l2_index_size; > diff --git a/ppc64.c b/ppc64.c > index 0a3aa5f..8ea91c2 100644 > --- a/ppc64.c > +++ b/ppc64.c > @@ -48,6 +48,10 @@ static ulong ppc64_get_stackbase(ulong); > static ulong ppc64_get_stacktop(ulong); > void ppc64_compiler_warning_stub(void); > static ulong ppc64_in_irqstack(ulong); > +static enum emergency_stack_type ppc64_in_emergency_stack(int cpu, ulong addr, > + bool verbose); > +static void ppc64_set_bt_emergency_stack(enum emergency_stack_type type, > + struct bt_info *bt); > static char * ppc64_check_eframe(struct ppc64_pt_regs *); > static void ppc64_print_eframe(char *, struct ppc64_pt_regs *, > struct bt_info *); > @@ -56,6 +60,7 @@ static int ppc64_paca_percpu_offset_init(int); > static void ppc64_init_cpu_info(void); > static int ppc64_get_cpu_map(void); > static void ppc64_clear_machdep_cache(void); > +static void ppc64_init_paca_info(void); > static void ppc64_vmemmap_init(void); > static int ppc64_get_kvaddr_ranges(struct vaddr_range *); > static uint get_ptetype(ulong pte); > @@ -692,6 +697,8 @@ ppc64_init(int when) > error(FATAL, "cannot malloc hwirqstack buffer space."); > } > > + ppc64_init_paca_info(); > + > if (!machdep->hz) { > machdep->hz = HZ; > if (THIS_KERNEL_VERSION >= LINUX(2,6,0)) > @@ -1204,6 +1211,70 @@ ppc64_kvtop(struct task_context *tc, ulong kvaddr, > return ppc64_vtop(kvaddr, (ulong *)vt->kernel_pgd[0], paddr, verbose); > } > > +static void > +ppc64_init_paca_info(void) > +{ > + struct machine_specific *ms = machdep->machspec; > + ulong *paca_ptr; > + int i; > + > + if (!(paca_ptrs = (ulong *)calloc(kt->cpus, sizeof(ulong)))) s/paca_ptrs/paca_ptr/ ppc64.c: In function ‘ppc64_init_paca_info’: ppc64.c:1219:8: error: ‘paca_ptrs’ undeclared (first use in this function); did you mean ‘paca_ptr’? if (!(paca_ptrs = (ulong *)calloc(kt->cpus, sizeof(ulong)))) ^~~~~~~~~ paca_ptr ppc64.c:1219:8: note: each undeclared identifier is reported only once for each function it appears in > + error(FATAL, "cannot malloc paca pointers space.\n"); > + > + /* Get paca pointers for all CPUs. */ > + if (symbol_exists("paca_ptrs")) { > + ulong paca_loc; > + > + readmem(symbol_value("paca_ptrs"), KVADDR, &paca_loc, sizeof(void *), > + "paca double pointer", FAULT_ON_ERROR); > + readmem(paca_loc, KVADDR, paca_ptr, sizeof(void *) * kt->cpus, > + "paca pointers", FAULT_ON_ERROR); > + } else if (symbol_exists("paca") && > + (get_symbol_type("paca", NULL, NULL) == TYPE_CODE_PTR)) { > + readmem(symbol_value("paca"), KVADDR, paca_ptr, sizeof(void *) * kt->cpus, > + "paca pointers", FAULT_ON_ERROR); > + } else { > + free(paca_ptrs); Ditto. > + return; > + } > + > + /* Initialize emergency stacks info. */ > + if (MEMBER_EXISTS("paca_struct", "emergency_sp")) { > + ulong offset = MEMBER_OFFSET("paca_struct", "emergency_sp"); > + > + if (!(ms->emergency_sp = (ulong *)calloc(kt->cpus, sizeof(ulong)))) > + error(FATAL, "cannot malloc emergency stack space.\n"); > + for (i = 0; i < kt->cpus; i++) > + readmem(paca_ptr[i] + offset, KVADDR, &ms->emergency_sp[i], > + sizeof(void *), "paca->emergency_sp", > + FAULT_ON_ERROR); > + } > + > + if (MEMBER_EXISTS("paca_struct", "nmi_emergency_sp")) { > + ulong offset = MEMBER_OFFSET("paca_struct", "nmi_emergency_sp"); > + > + if (!(ms->nmi_emergency_sp = (ulong *)calloc(kt->cpus, sizeof(ulong)))) > + error(FATAL, "cannot malloc NMI emergency stack space.\n"); > + for (i = 0; i < kt->cpus; i++) > + readmem(paca_ptr[i] + offset, KVADDR, &ms->nmi_emergency_sp[i], > + sizeof(void *), "paca->nmi_emergency_sp", > + FAULT_ON_ERROR); > + } > + > + if (MEMBER_EXISTS("paca_struct", "mc_emergency_sp")) { > + ulong offset = MEMBER_OFFSET("paca_struct", "mc_emergency_sp"); > + > + if (!(ms->mc_emergency_sp = (ulong *)calloc(kt->cpus, sizeof(ulong)))) > + error(FATAL, "cannot malloc machine check emergency stack space.\n"); > + for (i = 0; i < kt->cpus; i++) > + readmem(paca_ptr[i] + offset, KVADDR, &ms->mc_emergency_sp[i], > + sizeof(void *), "paca->mc_emergency_sp", > + FAULT_ON_ERROR); > + } > + > + free(paca_ptrs); Ditto. But these typos can be fixed when merging, no need to respin for this.