| Message ID | 20191125184944.15556-1-msys.mizuma@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | efi: arm64: Introduce /sys/firmware/efi/memreserve to tell the persistent pages | expand |
On 25/11/2019 19:49, Masayoshi Mizuma wrote: > From: Masayoshi Mizuma <m.mizuma@jp.fujitsu.com> > > kexec reboot stops in early boot sequence because efi_config_parse_tables() > refers garbage data. We can see the log with memblock=debug kernel option: > > efi: ACPI 2.0=0x9821790014 PROP=0x8757f5c0 SMBIOS 3.0=0x9820740000 MEMRESERVE=0x9820bfdc58 > memblock_reserve: [0x0000009820bfdc58-0x0000009820bfdc67] efi_config_parse_tables+0x228/0x278 > memblock_reserve: [0x0000000082760000-0x00000000324d07ff] efi_config_parse_tables+0x228/0x278 > memblock_reserve: [0xcc4f84ecc0511670-0x5f6e5214a7fd91f9] efi_config_parse_tables+0x244/0x278 > memblock_reserve: [0xd2fd4144b9af693d-0xad0c1db1086f40a2] efi_config_parse_tables+0x244/0x278 > memblock_reserve: [0x0c719bb159b1fadc-0x5aa6e62a1417ce12] efi_config_parse_tables+0x244/0x278 > ... > > That happens because 0x82760000, struct linux_efi_memreserve, is destroyed. > 0x82760000 is pointed from efi.mem_reseve, and efi.mem_reserve points the > head page of LPI pending table and LPI property table which are allocated by > gic_reserve_range(). > > The destroyer is kexec. kexec locates the initrd to the area: > > ]# kexec -d -l /boot/vmlinuz-5.4.0-rc7 /boot/initramfs-5.4.0-rc7.img --reuse-cmdline > ... > initrd: base 82290000, size 388dd8ah (59301258) > ... > > From dynamic debug log. initrd is located in segment[1]: > machine_kexec_prepare:70: > kexec kimage info: > type: 0 > start: 85b30680 > head: 0 > nr_segments: 4 > segment[0]: 0000000080480000 - 0000000082290000, 0x1e10000 bytes, 481 pages > segment[1]: 0000000082290000 - 0000000085b20000, 0x3890000 bytes, 905 pages > segment[2]: 0000000085b20000 - 0000000085b30000, 0x10000 bytes, 1 pages > segment[3]: 0000000085b30000 - 0000000085b40000, 0x10000 bytes, 1 pages > > kexec searches the memory region to locate initrd through > "System RAM" in /proc/iomem. The pending tables are included in > "System RAM" because they are allocated by alloc_pages(), so kexec > destroys the LPI pending tables. > Doesn't that mean that you haven't enough memory reserved so that you have to fallback to allocate it via __get_free_page()? > Introduce /sys/firmware/efi/memreserve to tell the pages pointed by > efi.mem_reserve so that kexec can avoid the area to locate initrd. > Doesn't that need a patch for kexec-tools to actually take this into account? > Signed-off-by: Masayoshi Mizuma <m.mizuma@jp.fujitsu.com> > --- > drivers/firmware/efi/efi.c | 45 +++++++++++++++++++++++++++++++++++++- > 1 file changed, 44 insertions(+), 1 deletion(-) > > diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c > index e98bbf8e5..0aa07cc09 100644 > --- a/drivers/firmware/efi/efi.c > +++ b/drivers/firmware/efi/efi.c > @@ -141,6 +141,47 @@ static ssize_t systab_show(struct kobject *kobj, > > static struct kobj_attribute efi_attr_systab = __ATTR_RO_MODE(systab, 0400); > > +static struct linux_efi_memreserve *efi_memreserve_root __ro_after_init; > +#ifdef CONFIG_KEXEC > +static ssize_t memreserve_show(struct kobject *kobj, > + struct kobj_attribute *attr, char *buf) > +{ > + struct linux_efi_memreserve *rsv; > + phys_addr_t start, end; > + unsigned long prsv; > + char *str = buf; > + int count, i; > + > + if (!kobj || !buf) > + return -EINVAL; > + > + if ((efi_memreserve_root == (void *)ULONG_MAX) || > + (!efi_memreserve_root)) > + return -ENODEV; > + > + for (prsv = efi_memreserve_root->next; prsv; prsv = rsv->next) { > + rsv = memremap(prsv, sizeof(*rsv), MEMREMAP_WB); > + if (!rsv) { > + pr_err("Could not map efi_memreserve\n"); > + return -ENOMEM; > + } > + count = atomic_read(&rsv->count); > + for (i = 0; i < count; i++) { > + start = rsv->entry[i].base; > + end = start + rsv->entry[i].size - 1; > + > + str += sprintf(str, "%pa-%pa\n", &start, &end); What happens if we provide a buf which is too small? Regards, Matthias
On Fri, Nov 29, 2019 at 01:25:36PM +0100, Matthias Brugger wrote: > > > On 25/11/2019 19:49, Masayoshi Mizuma wrote: > > From: Masayoshi Mizuma <m.mizuma@jp.fujitsu.com> > > > > kexec reboot stops in early boot sequence because efi_config_parse_tables() > > refers garbage data. We can see the log with memblock=debug kernel option: > > > > efi: ACPI 2.0=0x9821790014 PROP=0x8757f5c0 SMBIOS 3.0=0x9820740000 MEMRESERVE=0x9820bfdc58 > > memblock_reserve: [0x0000009820bfdc58-0x0000009820bfdc67] efi_config_parse_tables+0x228/0x278 > > memblock_reserve: [0x0000000082760000-0x00000000324d07ff] efi_config_parse_tables+0x228/0x278 > > memblock_reserve: [0xcc4f84ecc0511670-0x5f6e5214a7fd91f9] efi_config_parse_tables+0x244/0x278 > > memblock_reserve: [0xd2fd4144b9af693d-0xad0c1db1086f40a2] efi_config_parse_tables+0x244/0x278 > > memblock_reserve: [0x0c719bb159b1fadc-0x5aa6e62a1417ce12] efi_config_parse_tables+0x244/0x278 > > ... > > > > That happens because 0x82760000, struct linux_efi_memreserve, is destroyed. > > 0x82760000 is pointed from efi.mem_reseve, and efi.mem_reserve points the > > head page of LPI pending table and LPI property table which are allocated by > > gic_reserve_range(). > > > > The destroyer is kexec. kexec locates the initrd to the area: > > > > ]# kexec -d -l /boot/vmlinuz-5.4.0-rc7 /boot/initramfs-5.4.0-rc7.img --reuse-cmdline > > ... > > initrd: base 82290000, size 388dd8ah (59301258) > > ... > > > > From dynamic debug log. initrd is located in segment[1]: > > machine_kexec_prepare:70: > > kexec kimage info: > > type: 0 > > start: 85b30680 > > head: 0 > > nr_segments: 4 > > segment[0]: 0000000080480000 - 0000000082290000, 0x1e10000 bytes, 481 pages > > segment[1]: 0000000082290000 - 0000000085b20000, 0x3890000 bytes, 905 pages > > segment[2]: 0000000085b20000 - 0000000085b30000, 0x10000 bytes, 1 pages > > segment[3]: 0000000085b30000 - 0000000085b40000, 0x10000 bytes, 1 pages > > > > kexec searches the memory region to locate initrd through > > "System RAM" in /proc/iomem. The pending tables are included in > > "System RAM" because they are allocated by alloc_pages(), so kexec > > destroys the LPI pending tables. > > > > Doesn't that mean that you haven't enough memory reserved so that you have to > fallback to allocate it via __get_free_page()? That's a not fallback allocation. The pending tables and also property tables are allocated by alloc_pages() on its_allocate_prop_table() and its_allocate_pending_table(). > > > > Introduce /sys/firmware/efi/memreserve to tell the pages pointed by > > efi.mem_reserve so that kexec can avoid the area to locate initrd. > > > > Doesn't that need a patch for kexec-tools to actually take this into account? Yes, we need a patch for kexec-tools as well. I'm preparing the kexec patch. > > > Signed-off-by: Masayoshi Mizuma <m.mizuma@jp.fujitsu.com> > > --- > > drivers/firmware/efi/efi.c | 45 +++++++++++++++++++++++++++++++++++++- > > 1 file changed, 44 insertions(+), 1 deletion(-) > > > > diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c > > index e98bbf8e5..0aa07cc09 100644 > > --- a/drivers/firmware/efi/efi.c > > +++ b/drivers/firmware/efi/efi.c > > @@ -141,6 +141,47 @@ static ssize_t systab_show(struct kobject *kobj, > > > > static struct kobj_attribute efi_attr_systab = __ATTR_RO_MODE(systab, 0400); > > > > +static struct linux_efi_memreserve *efi_memreserve_root __ro_after_init; > > +#ifdef CONFIG_KEXEC > > +static ssize_t memreserve_show(struct kobject *kobj, > > + struct kobj_attribute *attr, char *buf) > > +{ > > + struct linux_efi_memreserve *rsv; > > + phys_addr_t start, end; > > + unsigned long prsv; > > + char *str = buf; > > + int count, i; > > + > > + if (!kobj || !buf) > > + return -EINVAL; > > + > > + if ((efi_memreserve_root == (void *)ULONG_MAX) || > > + (!efi_memreserve_root)) > > + return -ENODEV; > > + > > + for (prsv = efi_memreserve_root->next; prsv; prsv = rsv->next) { > > + rsv = memremap(prsv, sizeof(*rsv), MEMREMAP_WB); > > + if (!rsv) { > > + pr_err("Could not map efi_memreserve\n"); > > + return -ENOMEM; > > + } > > + count = atomic_read(&rsv->count); > > + for (i = 0; i < count; i++) { > > + start = rsv->entry[i].base; > > + end = start + rsv->entry[i].size - 1; > > + > > + str += sprintf(str, "%pa-%pa\n", &start, &end); > > What happens if we provide a buf which is too small? Good point. The strings may exceed the buffer size (PAGE_SIZE) in case efi_memreserve_root has a lot of entries. It might be better to use seq_printf() to show efi_memreserve_root... I'll move the file from a sysfs entry to a proc entry so that efi_memreserve_root can be handled by seq_printf(). Thanks, Masa
diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c index e98bbf8e5..0aa07cc09 100644 --- a/drivers/firmware/efi/efi.c +++ b/drivers/firmware/efi/efi.c @@ -141,6 +141,47 @@ static ssize_t systab_show(struct kobject *kobj, static struct kobj_attribute efi_attr_systab = __ATTR_RO_MODE(systab, 0400); +static struct linux_efi_memreserve *efi_memreserve_root __ro_after_init; +#ifdef CONFIG_KEXEC +static ssize_t memreserve_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buf) +{ + struct linux_efi_memreserve *rsv; + phys_addr_t start, end; + unsigned long prsv; + char *str = buf; + int count, i; + + if (!kobj || !buf) + return -EINVAL; + + if ((efi_memreserve_root == (void *)ULONG_MAX) || + (!efi_memreserve_root)) + return -ENODEV; + + for (prsv = efi_memreserve_root->next; prsv; prsv = rsv->next) { + rsv = memremap(prsv, sizeof(*rsv), MEMREMAP_WB); + if (!rsv) { + pr_err("Could not map efi_memreserve\n"); + return -ENOMEM; + } + count = atomic_read(&rsv->count); + for (i = 0; i < count; i++) { + start = rsv->entry[i].base; + end = start + rsv->entry[i].size - 1; + + str += sprintf(str, "%pa-%pa\n", &start, &end); + } + memunmap(rsv); + } + + return str - buf; +} + +static struct kobj_attribute efi_attr_memreserve = + __ATTR_RO_MODE(memreserve, 0444); +#endif /* CONFIG_KEXEC */ + #define EFI_FIELD(var) efi.var #define EFI_ATTR_SHOW(name) \ @@ -172,6 +213,9 @@ static struct attribute *efi_subsys_attrs[] = { &efi_attr_runtime.attr, &efi_attr_config_table.attr, &efi_attr_fw_platform_size.attr, +#ifdef CONFIG_KEXEC + &efi_attr_memreserve.attr, +#endif NULL, }; @@ -955,7 +999,6 @@ int efi_status_to_err(efi_status_t status) } static DEFINE_SPINLOCK(efi_mem_reserve_persistent_lock); -static struct linux_efi_memreserve *efi_memreserve_root __ro_after_init; static int __init efi_memreserve_map_root(void) {