On Tue, 05 Nov, at 04:20:12PM, dyoung at redhat.com wrote:
> kexec kernel will need exactly same mapping for
> efi runtime memory ranges. Thus here export the
> runtime ranges mapping to sysfs, kexec-tools
> will assemble them and pass to 2nd kernel via
> setup_data.
>
> Introducing a new directly /sys/firmware/efi/efi-runtime-map
> Just like /sys/firmware/memmap. Containing below attribute
> in each file of that directory:
> attribute num_pages phys_addr type virt_addr
>
> It will not work for efi 32bit. Only x86_64 currently.
>
> Signed-off-by: Dave Young <dyoung at redhat.com>
> ---
> Documentation/ABI/testing/sysfs-efi-runtime-map | 45 ++++++
> arch/x86/include/asm/efi.h | 3
> arch/x86/platform/efi/efi.c | 11 +
> drivers/firmware/efi/Kconfig | 10 +
> drivers/firmware/efi/Makefile | 1
> drivers/firmware/efi/efi-runtime-map.c | 164 ++++++++++++++++++++++++
> drivers/firmware/efi/efi.c | 3
> include/linux/efi.h | 6
> 8 files changed, 242 insertions(+), 1 deletion(-)
[...]
> @@ -852,6 +855,14 @@ static void efi_map_regions(void **new_m
>
> memcpy(*new_memmap + (*count * memmap.desc_size), md,
> memmap.desc_size);
> + if (md->type != EFI_BOOT_SERVICES_CODE &&
> + md->type != EFI_BOOT_SERVICES_DATA) {
> + efi_runtime_map = krealloc(efi_runtime_map,
> + (nr_efi_runtime_map + 1) *
> + sizeof(efi_memory_desc_t), GFP_KERNEL);
> + *(efi_runtime_map + nr_efi_runtime_map) = *md;
> + nr_efi_runtime_map++;
> + }
> (*count)++;
> }
You really need to be using 'memmap.desc_size' here and not
sizeof(efi_memory_desc_t) as the two may differ. Also, you should be
checking for failure of krealloc() and using memcpy() instead of
directly dereferencing 'md'.
> --- linux-2.6.orig/drivers/firmware/efi/Makefile
> +++ linux-2.6/drivers/firmware/efi/Makefile
> @@ -4,3 +4,4 @@
> obj-y += efi.o vars.o
> obj-$(CONFIG_EFI_VARS) += efivars.o
> obj-$(CONFIG_EFI_VARS_PSTORE) += efi-pstore.o
> +obj-$(CONFIG_EFI_RUNTIME_MAP) += efi-runtime-map.o
> --- /dev/null
> +++ linux-2.6/drivers/firmware/efi/efi-runtime-map.c
Small nit but I wouldn't bother prefixing the filename with "efi-",
since you can't build this file as a module.
> +/*
> + * These are default attributes that are added for every memmap entry.
> + */
> +static struct attribute *def_attrs[] = {
> + &map_type_attr.attr,
> + &map_phys_addr_attr.attr,
> + &map_virt_addr_attr.attr,
> + &map_num_pages_attr.attr,
> + &map_attribute_attr.attr,
> + NULL
> +};
If the UEFI spec ever releases an update for the memory descriptor
structure, and bumps 'memmap.desc_version', how are we going to signal
the incompatibility to legacy versions of kexec tools?
--
Matt Fleming, Intel Open Source Technology Center
