Hi Christophe, The latest series is https://lore.kernel.org/linuxppc-dev/20231017022806.4523-1-piliu@xxxxxxxxxx/ And Michael has his implement on: https://lore.kernel.org/all/20231229120107.2281153-3-mpe@xxxxxxxxxxxxxx/T/#m46128446bce1095631162a1927415733a3bf0633 Thanks, Pingfan On Fri, Jan 26, 2024 at 3:40 AM Christophe Leroy <christophe.leroy@xxxxxxxxxx> wrote: > > Hi, > > Le 22/05/2018 à 10:23, Pingfan Liu a écrit : > > For kexec -p, the boot cpu can be not the cpu0, this causes the problem > > to alloc paca[]. In theory, there is no requirement to assign cpu's logical > > id as its present seq by device tree. But we have something like > > cpu_first_thread_sibling(), which makes assumption on the mapping inside > > a core. Hence partially changing the mapping, i.e. unbind the mapping of > > core while keep the mapping inside a core. After this patch, the core with > > boot-cpu will always be mapped into core 0. > > > > And at present, the code to discovery cpu spreads over two functions: > > early_init_dt_scan_cpus() and smp_setup_cpu_maps(). > > This patch tries to fold smp_setup_cpu_maps() into the "previous" one > > This patch is pretty old and doesn't apply anymore. If still relevant > can you please rebase and resubmit. > > Thanks > Christophe > > > > > Signed-off-by: Pingfan Liu <kernelfans@xxxxxxxxx> > > --- > > v5 -> v6: > > simplify the loop logic (Hope it can answer Benjamin's concern) > > concentrate the cpu recovery code to early stage (Hope it can answer Michael's concern) > > Todo: (if this method is accepted) > > fold the whole smp_setup_cpu_maps() > > > > arch/powerpc/include/asm/smp.h | 1 + > > arch/powerpc/kernel/prom.c | 123 ++++++++++++++++++++++++++++--------- > > arch/powerpc/kernel/setup-common.c | 58 ++--------------- > > drivers/of/fdt.c | 2 +- > > include/linux/of_fdt.h | 2 + > > 5 files changed, 103 insertions(+), 83 deletions(-) > > > > diff --git a/arch/powerpc/include/asm/smp.h b/arch/powerpc/include/asm/smp.h > > index fac963e..80c7693 100644 > > --- a/arch/powerpc/include/asm/smp.h > > +++ b/arch/powerpc/include/asm/smp.h > > @@ -30,6 +30,7 @@ > > #include <asm/percpu.h> > > > > extern int boot_cpuid; > > +extern int threads_in_core; > > extern int spinning_secondaries; > > > > extern void cpu_die(void); > > diff --git a/arch/powerpc/kernel/prom.c b/arch/powerpc/kernel/prom.c > > index 4922162..2ae0b4a 100644 > > --- a/arch/powerpc/kernel/prom.c > > +++ b/arch/powerpc/kernel/prom.c > > @@ -77,7 +77,6 @@ unsigned long tce_alloc_start, tce_alloc_end; > > u64 ppc64_rma_size; > > #endif > > static phys_addr_t first_memblock_size; > > -static int __initdata boot_cpu_count; > > > > static int __init early_parse_mem(char *p) > > { > > @@ -305,6 +304,14 @@ static void __init check_cpu_feature_properties(unsigned long node) > > } > > } > > > > +struct bootinfo { > > + int boot_thread_id; > > + unsigned int cpu_cnt; > > + int cpu_hwids[NR_CPUS]; > > + bool avail[NR_CPUS]; > > +}; > > +static struct bootinfo *bt_info; > > + > > static int __init early_init_dt_scan_cpus(unsigned long node, > > const char *uname, int depth, > > void *data) > > @@ -312,10 +319,12 @@ static int __init early_init_dt_scan_cpus(unsigned long node, > > const char *type = of_get_flat_dt_prop(node, "device_type", NULL); > > const __be32 *prop; > > const __be32 *intserv; > > - int i, nthreads; > > + int i, nthreads, maxidx; > > int len; > > - int found = -1; > > - int found_thread = 0; > > + int found_thread = -1; > > + struct bootinfo *info = data; > > + bool avail; > > + int rotate_cnt, id; > > > > /* We are scanning "cpu" nodes only */ > > if (type == NULL || strcmp(type, "cpu") != 0) > > @@ -325,8 +334,15 @@ static int __init early_init_dt_scan_cpus(unsigned long node, > > intserv = of_get_flat_dt_prop(node, "ibm,ppc-interrupt-server#s", &len); > > if (!intserv) > > intserv = of_get_flat_dt_prop(node, "reg", &len); > > + avail = of_fdt_device_is_available(initial_boot_params, node); > > +#if 0 > > + //todo > > + if (!avail) > > + avail = !of_fdt_property_match_string(node, > > + "enable-method", "spin-table"); > > +#endif > > > > - nthreads = len / sizeof(int); > > + threads_in_core = nthreads = len / sizeof(int); > > > > /* > > * Now see if any of these threads match our boot cpu. > > @@ -338,9 +354,10 @@ static int __init early_init_dt_scan_cpus(unsigned long node, > > * booted proc. > > */ > > if (fdt_version(initial_boot_params) >= 2) { > > + info->cpu_hwids[info->cpu_cnt] = > > + be32_to_cpu(intserv[i]); > > if (be32_to_cpu(intserv[i]) == > > fdt_boot_cpuid_phys(initial_boot_params)) { > > - found = boot_cpu_count; > > found_thread = i; > > } > > } else { > > @@ -351,22 +368,37 @@ static int __init early_init_dt_scan_cpus(unsigned long node, > > */ > > if (of_get_flat_dt_prop(node, > > "linux,boot-cpu", NULL) != NULL) > > - found = boot_cpu_count; > > + found_thread = info->cpu_cnt; > > } > > + info->avail[info->cpu_cnt] = avail; > > + > > #ifdef CONFIG_SMP > > /* logical cpu id is always 0 on UP kernels */ > > - boot_cpu_count++; > > + info->cpu_cnt++; > > #endif > > } > > > > /* Not the boot CPU */ > > - if (found < 0) > > + if (found_thread < 0) > > return 0; > > > > - DBG("boot cpu: logical %d physical %d\n", found, > > + /* always mapping boot-core to core 0 to cope with kexec -p */ > > + maxidx = info->cpu_cnt - 1; > > + rotate_cnt = nthreads; > > + while (rotate_cnt-- > 0) { > > + avail = info->avail[maxidx]; > > + id = info->cpu_hwids[maxidx]; > > + for (i = maxidx; i > 0; i--) { > > + info->avail[i] = info->avail[i - 1]; > > + info->cpu_hwids[i] = info->cpu_hwids[i - 1]; > > + } > > + info->avail[i] = avail; > > + info->cpu_hwids[i] = id; > > + } > > + > > + info->boot_thread_id = found_thread; > > + DBG("boot cpu: logical %d physical %d\n", found_thread, > > be32_to_cpu(intserv[found_thread])); > > - boot_cpuid = found; > > - set_hard_smp_processor_id(found, be32_to_cpu(intserv[found_thread])); > > > > /* > > * PAPR defines "logical" PVR values for cpus that > > @@ -675,6 +707,55 @@ static void __init tm_init(void) > > static void tm_init(void) { } > > #endif /* CONFIG_PPC_TRANSACTIONAL_MEM */ > > > > +static void early_setup_cpu_mapping(void) > > +{ > > + unsigned int cpu, cnt; > > + int nr_cpus_aligned; > > + > > + bt_info = __va(memblock_alloc(sizeof(struct bootinfo), > > + sizeof(unsigned long))); > > + memset(bt_info, 0, sizeof(struct bootinfo)); > > + bt_info->boot_thread_id = -1; > > + /* Retrieve CPU related informations from the flat tree > > + * (altivec support, boot CPU ID, ...) > > + */ > > + of_scan_flat_dt(early_init_dt_scan_cpus, bt_info); > > + > > + if (bt_info->boot_thread_id < 0) { > > + pr_err("Failed to identify boot CPU !\n"); > > + BUG(); > > + } > > + > > + boot_cpuid = bt_info->boot_thread_id; > > + /* work around subcore mode */ > > + nr_cpus_aligned = _ALIGN_UP(nr_cpu_ids, threads_in_core); > > + if (nr_cpus_aligned != nr_cpu_ids) { > > + pr_info("nr_cpus is forced to be aligned up from: %d to: %d\n", > > + nr_cpu_ids, nr_cpus_aligned); > > + nr_cpu_ids = nr_cpus_aligned; > > + } > > + cnt = (nr_cpu_ids < bt_info->cpu_cnt) ? nr_cpu_ids > > + : bt_info->cpu_cnt; > > + > > + allocate_pacas(); > > + for (cpu = 0; cpu < cnt; cpu++) { > > + set_cpu_present(cpu, bt_info->avail[cpu]); > > + DBG("set cpu present: %d -> hwid:%d\n", > > + cpu, bt_info->cpu_hwids[cpu]); > > + set_hard_smp_processor_id(cpu, bt_info->cpu_hwids[cpu]); > > + set_cpu_possible(cpu, true); > > + } > > + > > +#if defined(CONFIG_SMP) && defined(CONFIG_PPC64) > > + /* We'll later wait for secondaries to check in; there are > > + * NCPUS-1 non-boot CPUs :-) > > + */ > > + spinning_secondaries = bt_info->cpu_cnt - 1; > > +#endif > > + memblock_free(__pa(bt_info), sizeof(struct bootinfo)); > > + bt_info = NULL; > > +} > > + > > void __init early_init_devtree(void *params) > > { > > phys_addr_t limit; > > @@ -745,27 +826,11 @@ void __init early_init_devtree(void *params) > > * FIXME .. and the initrd too? */ > > move_device_tree(); > > > > - allocate_pacas(); > > - > > DBG("Scanning CPUs ...\n"); > > > > dt_cpu_ftrs_scan(); > > > > - /* Retrieve CPU related informations from the flat tree > > - * (altivec support, boot CPU ID, ...) > > - */ > > - of_scan_flat_dt(early_init_dt_scan_cpus, NULL); > > - if (boot_cpuid < 0) { > > - printk("Failed to identify boot CPU !\n"); > > - BUG(); > > - } > > - > > -#if defined(CONFIG_SMP) && defined(CONFIG_PPC64) > > - /* We'll later wait for secondaries to check in; there are > > - * NCPUS-1 non-boot CPUs :-) > > - */ > > - spinning_secondaries = boot_cpu_count - 1; > > -#endif > > + early_setup_cpu_mapping(); > > > > mmu_early_init_devtree(); > > > > diff --git a/arch/powerpc/kernel/setup-common.c b/arch/powerpc/kernel/setup-common.c > > index 66f7cc6..46d034a 100644 > > --- a/arch/powerpc/kernel/setup-common.c > > +++ b/arch/powerpc/kernel/setup-common.c > > @@ -86,7 +86,9 @@ struct machdep_calls *machine_id; > > EXPORT_SYMBOL(machine_id); > > > > int boot_cpuid = -1; > > +int threads_in_core = 1; > > EXPORT_SYMBOL_GPL(boot_cpuid); > > +EXPORT_SYMBOL_GPL(threads_in_core); > > > > /* > > * These are used in binfmt_elf.c to put aux entries on the stack > > @@ -460,61 +462,11 @@ void __init smp_setup_cpu_maps(void) > > { > > struct device_node *dn; > > int cpu = 0; > > - int nthreads = 1; > > - > > - DBG("smp_setup_cpu_maps()\n"); > > - > > - for_each_node_by_type(dn, "cpu") { > > - const __be32 *intserv; > > - __be32 cpu_be; > > - int j, len; > > - > > - DBG(" * %pOF...\n", dn); > > - > > - intserv = of_get_property(dn, "ibm,ppc-interrupt-server#s", > > - &len); > > - if (intserv) { > > - DBG(" ibm,ppc-interrupt-server#s -> %d threads\n", > > - nthreads); > > - } else { > > - DBG(" no ibm,ppc-interrupt-server#s -> 1 thread\n"); > > - intserv = of_get_property(dn, "reg", &len); > > - if (!intserv) { > > - cpu_be = cpu_to_be32(cpu); > > - intserv = &cpu_be; /* assume logical == phys */ > > - len = 4; > > - } > > - } > > - > > - nthreads = len / sizeof(int); > > - > > - for (j = 0; j < nthreads && cpu < nr_cpu_ids; j++) { > > - bool avail; > > - > > - DBG(" thread %d -> cpu %d (hard id %d)\n", > > - j, cpu, be32_to_cpu(intserv[j])); > > - > > - avail = of_device_is_available(dn); > > - if (!avail) > > - avail = !of_property_match_string(dn, > > - "enable-method", "spin-table"); > > - > > - set_cpu_present(cpu, avail); > > - set_hard_smp_processor_id(cpu, be32_to_cpu(intserv[j])); > > - set_cpu_possible(cpu, true); > > - cpu++; > > - } > > - > > - if (cpu >= nr_cpu_ids) { > > - of_node_put(dn); > > - break; > > - } > > - } > > > > /* If no SMT supported, nthreads is forced to 1 */ > > if (!cpu_has_feature(CPU_FTR_SMT)) { > > DBG(" SMT disabled ! nthreads forced to 1\n"); > > - nthreads = 1; > > + threads_in_core = 1; > > } > > > > #ifdef CONFIG_PPC64 > > @@ -539,7 +491,7 @@ void __init smp_setup_cpu_maps(void) > > > > /* Double maxcpus for processors which have SMT capability */ > > if (cpu_has_feature(CPU_FTR_SMT)) > > - maxcpus *= nthreads; > > + maxcpus *= threads_in_core; > > > > if (maxcpus > nr_cpu_ids) { > > printk(KERN_WARNING > > @@ -565,7 +517,7 @@ void __init smp_setup_cpu_maps(void) > > * every CPU in the system. If that is not the case, then some code > > * here will have to be reworked > > */ > > - cpu_init_thread_core_maps(nthreads); > > + cpu_init_thread_core_maps(threads_in_core); > > > > /* Now that possible cpus are set, set nr_cpu_ids for later use */ > > setup_nr_cpu_ids(); > > diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c > > index 84aa9d6..16d6b02 100644 > > --- a/drivers/of/fdt.c > > +++ b/drivers/of/fdt.c > > @@ -130,7 +130,7 @@ bool of_fdt_is_big_endian(const void *blob, unsigned long node) > > return false; > > } > > > > -static bool of_fdt_device_is_available(const void *blob, unsigned long node) > > +bool of_fdt_device_is_available(const void *blob, unsigned long node) > > { > > const char *status = fdt_getprop(blob, node, "status", NULL); > > > > diff --git a/include/linux/of_fdt.h b/include/linux/of_fdt.h > > index b9cd9eb..28756c5 100644 > > --- a/include/linux/of_fdt.h > > +++ b/include/linux/of_fdt.h > > @@ -30,6 +30,8 @@ extern void *of_fdt_get_property(const void *blob, > > int *size); > > extern bool of_fdt_is_big_endian(const void *blob, > > unsigned long node); > > +extern bool of_fdt_device_is_available(const void *blob, > > + unsigned long node); > > extern int of_fdt_match(const void *blob, unsigned long node, > > const char *const *compat); > > extern void *of_fdt_unflatten_tree(const unsigned long *blob, > _______________________________________________ > kexec mailing list > kexec@xxxxxxxxxxxxxxxxxxx > http://lists.infradead.org/mailman/listinfo/kexec _______________________________________________ kexec mailing list kexec@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/kexec
