Re: [PATCH 13/13] kexec: Support kexec/kdump on EFI systems

From: Borislav Petkov
Date: Wed Jun 18 2014 - 12:06:19 EST

Addomg linux-efi to CC for the efi bits. Please CC it on your next
submission.

Thanks.

On Tue, Jun 03, 2014 at 09:07:02AM -0400, Vivek Goyal wrote:
> This patch does two thigns. It passes EFI run time mappings to second
> kernel in bootparams efi_info. Second kernel parse this info and create
> new mappings in second kernel. That means mappings in first and second
> kernel will be same. This paves the way to enable EFI in kexec kernel.
>
> This patch also prepares and passes EFI setup data through bootparams.
> This contains bunch of information about various tables and their
> addresses.
>
> These information gathering and passing has been written along the lines
> of what current kexec-tools is doing to make kexec work with UEFI.
>
> Signed-off-by: Vivek Goyal <vgoyal@xxxxxxxxxx>
> ---
> arch/x86/include/asm/kexec.h | 4 +-
> arch/x86/kernel/kexec-bzimage.c | 40 ++++++++++++----
> arch/x86/kernel/machine_kexec.c | 93 ++++++++++++++++++++++++++++++++++++--
> drivers/firmware/efi/runtime-map.c | 21 +++++++++
> include/linux/efi.h | 19 ++++++++
> 5 files changed, 163 insertions(+), 14 deletions(-)
>
> diff --git a/arch/x86/include/asm/kexec.h b/arch/x86/include/asm/kexec.h
> index 4cbe5f7..d8461cf 100644
> --- a/arch/x86/include/asm/kexec.h
> +++ b/arch/x86/include/asm/kexec.h
> @@ -214,7 +214,9 @@ extern int kexec_setup_cmdline(struct kimage *image,
> unsigned long cmdline_offset, char *cmdline,
> unsigned long cmdline_len);
> extern int kexec_setup_boot_parameters(struct kimage *image,
> - struct boot_params *params);
> + struct boot_params *params, unsigned long params_load_addr,
> + unsigned int efi_map_offset, unsigned int efi_map_sz,
> + unsigned int efi_setup_data_offset);
>
>
> #endif /* __ASSEMBLY__ */
> diff --git a/arch/x86/kernel/kexec-bzimage.c b/arch/x86/kernel/kexec-bzimage.c
> index 8e762d3..55716e1 100644
> --- a/arch/x86/kernel/kexec-bzimage.c
> +++ b/arch/x86/kernel/kexec-bzimage.c
> @@ -15,10 +15,12 @@
> #include <linux/kexec.h>
> #include <linux/kernel.h>
> #include <linux/mm.h>
> +#include <linux/efi.h>
>
> #include <asm/bootparam.h>
> #include <asm/setup.h>
> #include <asm/crash.h>
> +#include <asm/efi.h>
>
> #define MAX_ELFCOREHDR_STR_LEN 30 /* elfcorehdr=0x<64bit-value> */
>
> @@ -106,7 +108,7 @@ void *bzImage64_load(struct kimage *image, char *kernel,
>
> struct setup_header *header;
> int setup_sects, kern16_size, ret = 0;
> - unsigned long setup_header_size, params_cmdline_sz;
> + unsigned long setup_header_size, params_cmdline_sz, params_misc_sz;
> struct boot_params *params;
> unsigned long bootparam_load_addr, kernel_load_addr, initrd_load_addr;
> unsigned long purgatory_load_addr;
> @@ -116,6 +118,7 @@ void *bzImage64_load(struct kimage *image, char *kernel,
> struct kexec_entry64_regs regs64;
> void *stack;
> unsigned int setup_hdr_offset = offsetof(struct boot_params, hdr);
> + unsigned int efi_map_offset, efi_map_sz, efi_setup_data_offset;
>
> header = (struct setup_header *)(kernel + setup_hdr_offset);
> setup_sects = header->setup_sects;
> @@ -168,28 +171,47 @@ void *bzImage64_load(struct kimage *image, char *kernel,
>
> pr_debug("Loaded purgatory at 0x%lx\n", purgatory_load_addr);
>
> - /* Load Bootparams and cmdline */
> +
> + /*
> + * Load Bootparams and cmdline and space for efi stuff.
> + *
> + * Allocate memory together for multiple data structures so
> + * that they all can go in single area/segment and we don't
> + * have to create separate segment for each. Keeps things
> + * little bit simple
> + */
> + efi_map_sz = get_efi_runtime_map_size();
> + efi_map_sz = ALIGN(efi_map_sz, 16);
> +
> params_cmdline_sz = sizeof(struct boot_params) + cmdline_len +
> MAX_ELFCOREHDR_STR_LEN;
> - params = kzalloc(params_cmdline_sz, GFP_KERNEL);
> + params_cmdline_sz = ALIGN(params_cmdline_sz, 16);
> + params_misc_sz = params_cmdline_sz + efi_map_sz +
> + sizeof(struct setup_data) +
> + sizeof(struct efi_setup_data);
> +
> + params = kzalloc(params_misc_sz, GFP_KERNEL);
> if (!params) {
> ret = -ENOMEM;
> goto out_free_loader_data;
> }
>
> + efi_map_offset = params_cmdline_sz;
> + efi_setup_data_offset = efi_map_offset + efi_map_sz;
> +
> /* Copy setup header onto bootparams. Documentation/x86/boot.txt */
> setup_header_size = 0x0202 + kernel[0x0201] - setup_hdr_offset;
>
> /* Is there a limit on setup header size? */
> memcpy(&params->hdr, (kernel + setup_hdr_offset), setup_header_size);
>
> - ret = kexec_add_buffer(image, (char *)params, params_cmdline_sz,
> - params_cmdline_sz, 16, MIN_BOOTPARAM_ADDR,
> + ret = kexec_add_buffer(image, (char *)params, params_misc_sz,
> + params_misc_sz, 16, MIN_BOOTPARAM_ADDR,
> ULONG_MAX, 1, &bootparam_load_addr);
> if (ret)
> goto out_free_params;
> - pr_debug("Loaded boot_param and command line at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
> - bootparam_load_addr, params_cmdline_sz, params_cmdline_sz);
> + pr_debug("Loaded boot_param, command line and misc at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
> + bootparam_load_addr, params_misc_sz, params_misc_sz);
>
> /* Load kernel */
> kernel_buf = kernel + kern16_size;
> @@ -254,7 +276,9 @@ void *bzImage64_load(struct kimage *image, char *kernel,
> if (ret)
> goto out_free_params;
>
> - ret = kexec_setup_boot_parameters(image, params);
> + ret = kexec_setup_boot_parameters(image, params, bootparam_load_addr,
> + efi_map_offset, efi_map_sz,
> + efi_setup_data_offset);
> if (ret)
> goto out_free_params;
>
> diff --git a/arch/x86/kernel/machine_kexec.c b/arch/x86/kernel/machine_kexec.c
> index 6a3821b..f31a4b5 100644
> --- a/arch/x86/kernel/machine_kexec.c
> +++ b/arch/x86/kernel/machine_kexec.c
> @@ -12,9 +12,11 @@
> #include <linux/kernel.h>
> #include <linux/kexec.h>
> #include <linux/string.h>
> +#include <linux/efi.h>
> #include <asm/bootparam.h>
> #include <asm/setup.h>
> #include <asm/crash.h>
> +#include <asm/efi.h>
>
> /*
> * Common code for x86 and x86_64 used for kexec.
> @@ -67,11 +69,10 @@ int kexec_setup_cmdline(struct kimage *image, struct boot_params *params,
> return 0;
> }
>
> -static int setup_memory_map_entries(struct boot_params *params)
> +static int setup_e820_entries(struct boot_params *params)
> {
> unsigned int nr_e820_entries;
>
> - /* TODO: What about EFI */
> nr_e820_entries = e820_saved.nr_map;
> if (nr_e820_entries > E820MAX)
> nr_e820_entries = E820MAX;
> @@ -83,8 +84,85 @@ static int setup_memory_map_entries(struct boot_params *params)
> return 0;
> }
>
> -int kexec_setup_boot_parameters(struct kimage *image,
> - struct boot_params *params)
> +#ifdef CONFIG_EFI
> +static int setup_efi_info_memmap(struct boot_params *params,
> + unsigned long params_load_addr,
> + unsigned int efi_map_offset,
> + unsigned int efi_map_sz)
> +{
> + void *efi_map = (void *)params + efi_map_offset;
> + unsigned long efi_map_phys_addr = params_load_addr + efi_map_offset;
> + struct efi_info *ei = &params->efi_info;
> +
> + if (!efi_map_sz)
> + return 0;
> +
> + efi_runtime_map_copy(efi_map, efi_map_sz);
> +
> + ei->efi_memmap = efi_map_phys_addr & 0xffffffff;
> + ei->efi_memmap_hi = efi_map_phys_addr >> 32;
> + ei->efi_memmap_size = efi_map_sz;
> +
> + return 0;
> +}
> +
> +static int
> +prepare_add_efi_setup_data(struct boot_params *params,
> + unsigned long params_load_addr,
> + unsigned int efi_setup_data_offset)
> +{
> + unsigned long setup_data_phys;
> + struct setup_data *sd = (void *)params + efi_setup_data_offset;
> + struct efi_setup_data *esd = (void *)sd + sizeof(struct setup_data);
> +
> + esd->fw_vendor = efi.fw_vendor;
> + esd->runtime = efi.runtime;
> + esd->tables = efi.config_table;
> + esd->smbios = efi.smbios;
> +
> + sd->type = SETUP_EFI;
> + sd->len = sizeof(struct efi_setup_data);
> +
> + /* Add setup data */
> + setup_data_phys = params_load_addr + efi_setup_data_offset;
> + sd->next = params->hdr.setup_data;
> + params->hdr.setup_data = setup_data_phys;
> +
> + return 0;
> +}
> +
> +static int setup_efi_state(struct boot_params *params,
> + unsigned long params_load_addr,
> + unsigned int efi_map_offset, unsigned int efi_map_sz,
> + unsigned int efi_setup_data_offset)
> +{
> + struct efi_info *current_ei = &boot_params.efi_info;
> + struct efi_info *ei = &params->efi_info;
> +
> + if (!current_ei->efi_memmap_size)
> + return 0;
> +
> + ei->efi_loader_signature = current_ei->efi_loader_signature;
> + ei->efi_systab = current_ei->efi_systab;
> + ei->efi_systab_hi = current_ei->efi_systab_hi;
> +
> + ei->efi_memdesc_version = current_ei->efi_memdesc_version;
> + ei->efi_memdesc_size = get_efi_runtime_map_desc_size();
> +
> + setup_efi_info_memmap(params, params_load_addr, efi_map_offset,
> + efi_map_sz);
> + prepare_add_efi_setup_data(params, params_load_addr,
> + efi_setup_data_offset);
> + return 0;
> +}
> +#endif /* CONFIG_EFI */
> +
> +int
> +kexec_setup_boot_parameters(struct kimage *image, struct boot_params *params,
> + unsigned long params_load_addr,
> + unsigned int efi_map_offset,
> + unsigned int efi_map_sz,
> + unsigned int efi_setup_data_offset)
> {
> unsigned int nr_e820_entries;
> unsigned long long mem_k, start, end;
> @@ -114,7 +192,7 @@ int kexec_setup_boot_parameters(struct kimage *image,
> if (image->type == KEXEC_TYPE_CRASH)
> crash_setup_memmap_entries(image, params);
> else
> - setup_memory_map_entries(params);
> + setup_e820_entries(params);
>
> nr_e820_entries = params->e820_entries;
>
> @@ -135,6 +213,11 @@ int kexec_setup_boot_parameters(struct kimage *image,
> }
> }
>
> +#ifdef CONFIG_EFI
> + /* Setup EFI state */
> + setup_efi_state(params, params_load_addr, efi_map_offset, efi_map_sz,
> + efi_setup_data_offset);
> +#endif
> /* Setup EDD info */
> memcpy(params->eddbuf, boot_params.eddbuf,
> EDDMAXNR * sizeof(struct edd_info));
> diff --git a/drivers/firmware/efi/runtime-map.c b/drivers/firmware/efi/runtime-map.c
> index 97cdd16..40f2213 100644
> --- a/drivers/firmware/efi/runtime-map.c
> +++ b/drivers/firmware/efi/runtime-map.c
> @@ -138,6 +138,27 @@ add_sysfs_runtime_map_entry(struct kobject *kobj, int nr)
> return entry;
> }
>
> +int get_efi_runtime_map_size(void)
> +{
> + return nr_efi_runtime_map * efi_memdesc_size;
> +}
> +
> +int get_efi_runtime_map_desc_size(void)
> +{
> + return efi_memdesc_size;
> +}
> +
> +int efi_runtime_map_copy(void *buf, size_t bufsz)
> +{
> + size_t sz = get_efi_runtime_map_size();
> +
> + if (sz > bufsz)
> + sz = bufsz;
> +
> + memcpy(buf, efi_runtime_map, sz);
> + return 0;
> +}
> +
> void efi_runtime_map_setup(void *map, int nr_entries, u32 desc_size)
> {
> efi_runtime_map = map;
> diff --git a/include/linux/efi.h b/include/linux/efi.h
> index 6c100ff..c2e5c4a 100644
> --- a/include/linux/efi.h
> +++ b/include/linux/efi.h
> @@ -1131,6 +1131,9 @@ int efivars_sysfs_init(void);
> #ifdef CONFIG_EFI_RUNTIME_MAP
> int efi_runtime_map_init(struct kobject *);
> void efi_runtime_map_setup(void *, int, u32);
> +int get_efi_runtime_map_size(void);
> +int get_efi_runtime_map_desc_size(void);
> +int efi_runtime_map_copy(void *buf, size_t bufsz);
> #else
> static inline int efi_runtime_map_init(struct kobject *kobj)
> {
> @@ -1139,6 +1142,22 @@ static inline int efi_runtime_map_init(struct kobject *kobj)
>
> static inline void
> efi_runtime_map_setup(void *map, int nr_entries, u32 desc_size) {}
> +
> +static inline int get_efi_runtime_map_size(void)
> +{
> + return 0;
> +}
> +
> +static inline int get_efi_runtime_map_desc_size(void)
> +{
> + return 0;
> +}
> +
> +static inline int efi_runtime_map_copy(void *buf, size_t bufsz)
> +{
> + return 0;
> +}
> +
> #endif
>
> #endif /* _LINUX_EFI_H */
> --
> 1.9.0
>
>

--
Regards/Gruss,
Boris.

Sent from a fat crate under my desk. Formatting is fine.
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