| Message ID | 20191114161019.8735-1-msys.mizuma@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [RFC,v2] efi: arm64: Introduce /sys/firmware/efi/memreserve to tell the persistent pages | expand |
On Thu, Nov 14, 2019 at 11:10:19AM -0500, 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. > > Introduce /sys/firmware/efi/memreserve to tell the pages pointed by > efi.mem_reserve so that kexec can avoid the area to locate initrd. > > Signed-off-by: Masayoshi Mizuma <m.mizuma@jp.fujitsu.com> > --- > drivers/firmware/efi/efi.c | 41 +++++++++++++++++++++++++++++++++++++- > 1 file changed, 40 insertions(+), 1 deletion(-) > > diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c > index 0b6b0c19a..07812d697 100644 > --- a/drivers/firmware/efi/efi.c > +++ b/drivers/firmware/efi/efi.c > @@ -149,6 +149,45 @@ 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; > +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); > + I think it's better to put above between #ifdef CONFIG_KEXEC and #endif because it's useful for only kexec... > #define EFI_FIELD(var) efi.var > > #define EFI_ATTR_SHOW(name) \ > @@ -180,6 +219,7 @@ static struct attribute *efi_subsys_attrs[] = { > &efi_attr_runtime.attr, > &efi_attr_config_table.attr, > &efi_attr_fw_platform_size.attr, > + &efi_attr_memreserve.attr, Same as. I'll post the patch to change above and will remove the RFC. Thanks, Masa > NULL, > }; > > @@ -964,7 +1004,6 @@ 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) > { > -- > 2.21.0 >
diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c index 0b6b0c19a..07812d697 100644 --- a/drivers/firmware/efi/efi.c +++ b/drivers/firmware/efi/efi.c @@ -149,6 +149,45 @@ 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; +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); + #define EFI_FIELD(var) efi.var #define EFI_ATTR_SHOW(name) \ @@ -180,6 +219,7 @@ static struct attribute *efi_subsys_attrs[] = { &efi_attr_runtime.attr, &efi_attr_config_table.attr, &efi_attr_fw_platform_size.attr, + &efi_attr_memreserve.attr, NULL, }; @@ -964,7 +1004,6 @@ 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) {