Re: [PATCH v4 07/12] efi: passing kexec necessary efi data via setup_data

Borislav Petkov
2013-11-27T14:07:32Z

On Tue, Nov 26, 2013 at 01:57:52PM +0800, Dave Young wrote:
> Add a new setup_data type SETUP_EFI for kexec use.
> Passing the saved fw_vendor, runtime, config tables and
> efi runtime mappings.
>
> When entering virtual mode, directly mapping the efi
> runtime ragions which we passed in previously. And skip
> the step to call SetVirtualAddressMap.
>
> Specially for HP z420 workstation it need another variable
> saving,

Why the special handling? Does that mean, this is going to be the case
for other HP UEFI implementations too?

> it's the smbios physical address, the HP bios
> also update the SMBIOS address after entering virtual mode
> besides of the standard fw_vendor,runtime and config table.
>
> Tested on ovmf+qemu, lenovo thinkpad, a dell laptop and an
> HP z420 workstation.
>
> v2: refresh based on previous patch changes, code cleanup.
> v3: use ioremap instead of phys_to_virt for esdata
>
> Signed-off-by: Dave Young <dyoung-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
> ---
> arch/x86/include/asm/efi.h | 12 +++
> arch/x86/include/uapi/asm/bootparam.h | 1 +
> arch/x86/kernel/setup.c | 3 +
> arch/x86/platform/efi/efi.c | 161 ++++++++++++++++++++++++++++++----
> 4 files changed, 160 insertions(+), 17 deletions(-)
>
> diff --git a/arch/x86/include/asm/efi.h b/arch/x86/include/asm/efi.h
> index 9fbaeb2..73d5643 100644
> --- a/arch/x86/include/asm/efi.h
> +++ b/arch/x86/include/asm/efi.h
> @@ -133,6 +133,18 @@ extern void efi_sync_low_kernel_mappings(void);
> extern void efi_setup_page_tables(void);
> extern void __init old_map_region(efi_memory_desc_t *md);
>
> +struct efi_setup_data {
> + u64 fw_vendor;
> + u64 runtime;
> + u64 tables;
> + u64 smbios;
> + u64 reserved[8];

What's that for?

> + efi_memory_desc_t map[0];
> +};
> +
> +extern void parse_efi_setup(u64 phys_addr, u32 data_len);
> +extern struct efi_setup_data *esdata;
> +
> #ifdef CONFIG_EFI
>
> static inline bool efi_is_native(void)

[ … ]

> diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
> index c3a2aaa..fafeb40 100644
> --- a/arch/x86/platform/efi/efi.c
> +++ b/arch/x86/platform/efi/efi.c
> @@ -504,8 +531,12 @@ static int __init efi_systab_init(void *phys)
> }
>
> efi_systab.hdr = systab64->hdr;
> - efi_systab.fw_vendor = systab64->fw_vendor;
> - tmp |= systab64->fw_vendor;
> +
> + if (esdata)
> + efi_systab.fw_vendor = (unsigned long)esdata->fw_vendor;
> + else
> + efi_systab.fw_vendor = systab64->fw_vendor;

efi_systab.fw_vendor = esdata ? (unsigned long)esdata->fw_vendor
: systab64->fw_vendor;

> + tmp |= efi_systab.fw_vendor;
> efi_systab.fw_revision = systab64->fw_revision;
> efi_systab.con_in_handle = systab64->con_in_handle;
> tmp |= systab64->con_in_handle;
> @@ -519,13 +550,21 @@ static int __init efi_systab_init(void *phys)
> tmp |= systab64->stderr_handle;
> efi_systab.stderr = systab64->stderr;
> tmp |= systab64->stderr;
> - efi_systab.runtime = (void *)(unsigned long)systab64->runtime;
> - tmp |= systab64->runtime;
> + if (esdata)
> + efi_systab.runtime =
> + (void *)(unsigned long)esdata->runtime;
> + else
> + efi_systab.runtime =
> + (void *)(unsigned long)systab64->runtime;

Ditto. Which would take care of these linebreaks which are ugly.

> + tmp |= (unsigned long)efi_systab.runtime;
> efi_systab.boottime = (void *)(unsigned long)systab64->boottime;
> tmp |= systab64->boottime;
> efi_systab.nr_tables = systab64->nr_tables;
> - efi_systab.tables = systab64->tables;
> - tmp |= systab64->tables;
> + if (esdata)
> + efi_systab.tables = (unsigned long)esdata->tables;
> + else
> + efi_systab.tables = systab64->tables;

Ditto.

> + tmp |= efi_systab.tables;
>
> early_iounmap(systab64, sizeof(*systab64));
> #ifdef CONFIG_X86_32
> @@ -631,6 +670,41 @@ static int __init efi_memmap_init(void)
> return 0;
> }
>
> +static int __init efi_reuse_config(u64 tables, int nr_tables)

Static function - no need for "efi_" prefix.

> +{
> + void *p, *tablep;
> + int i, sz;
> +
> + if (!efi_enabled(EFI_64BIT))
> + return 0;
> +
> + sz = sizeof(efi_config_table_64_t);
> +
> + p = tablep = early_memremap(tables, nr_tables * sz);
> + if (!p) {
> + pr_err("Could not map Configuration table!\n");
> + return -ENOMEM;
> + }
> +
> + for (i = 0; i < efi.systab->nr_tables; i++) {
> + efi_guid_t guid;
> +
> + guid = ((efi_config_table_64_t *)p)->guid;
> +
> + /*
> + HP z420 workstation smbios will be convert to
> + virtual address after enter virtual mode.
> + Thus in case kexec/kdump the physical address
> + will be passed in setup_data.

Is that what the commit message above says? I'm having a hard time
parsing this text.

> + */
> + if (!efi_guidcmp(guid, SMBIOS_TABLE_GUID))
> + ((efi_config_table_64_t *)p)->table = esdata->smbios;

...and yet we do this for *every* UEFI box. Why not HP only?

> + p += sz;
> + }
> + early_iounmap(tablep, nr_tables * sz);
> + return 0;
> +}
> +
> void __init efi_init(void)
> {
> efi_char16_t *c16;
> @@ -676,6 +750,9 @@ void __init efi_init(void)
> efi.systab->hdr.revision >> 16,
> efi.systab->hdr.revision & 0xffff, vendor);
>
> + if (esdata && esdata->smbios)
> + efi_reuse_config(efi.systab->tables, efi.systab->nr_tables);
> +
> if (efi_config_init(arch_tables))
> return;
>
> @@ -886,6 +963,43 @@ ret:
> }
>
> /*
> + * map efi regions which was passed via setup_data
> + * the virt_addr is a fixed addr which was used in
> + * 1st kernel of kexec boot.
> + */

Comment to 80 cols pls.

> +static void __init efi_map_regions_fixed(void)

Also no need for "efi_" prefix here.

> +{
> + int i;
> + unsigned long size;
> + efi_memory_desc_t *md;
> + u64 end, systab;
> + void *p;
> +
> + efi_runtime_map = kzalloc(nr_efi_runtime_map * memmap.desc_size,
> + GFP_KERNEL);

Arg alignment.

> + if (!efi_runtime_map)
> + pr_err("Out of memory, EFI runtime on nested kexec non-functional!\n");
> +
> + for (i = 0, p = efi_runtime_map; i < nr_efi_runtime_map; i++) {
> + md = esdata->map + i;
> + efi_map_region_fixed(md);

Gaah, this function should probably have a retval which signalizes
success/failure. For that I should probably teach __map_region to do
that too. On the TODO list.

> + size = md->num_pages << PAGE_SHIFT;
> + end = md->phys_addr + size;
> +
> + systab = (u64) (unsigned long) efi_phys.systab;
> + if (md->phys_addr <= systab && systab < end) {
> + systab += md->virt_addr - md->phys_addr;
> + efi.systab =
> + (efi_system_table_t *) (unsigned long) systab;

CHECK: No space is necessary after a cast
#219: FILE: arch/x86/platform/efi/efi.c:993:
+ efi.systab =
+ (efi_system_table_t *) (unsigned long) systab;

And also, those broken lines are ugly. Just let it stick out over 80 cols.

> + }
> + if (efi_runtime_map) {
> + memcpy(p, md, memmap.desc_size);
> + p += memmap.desc_size;
> + }
> + }
> +}
> +
> +/*
> * This function will switch the EFI runtime services to virtual mode.
> * Essentially, we look through the EFI memmap and map every region that
> * has the runtime attribute bit set in its memory descriptor into the
> @@ -901,6 +1015,10 @@ ret:
> * so that we're in a different address space when calling a runtime
> * function. For function arguments passing we do copy the PGDs of the
> * kernel page table into ->trampoline_pgd prior to each call.
> + *
> + * Specially for kexec boot efi runtime maps in previous kernel should

boot, ...

> + * be passed in via setup_data. In that case runtime ranges will be mapped

case, ...

> + * to fixed virtual addresses exactly same as the ones in previous kernel.

"... to the same virtual addresses as the first kernel."

> */
> void __init efi_enter_virtual_mode(void)
> {
> @@ -919,12 +1037,15 @@ void __init efi_enter_virtual_mode(void)
> return;
> }
>
> - efi_merge_regions();
> -
> - new_memmap = efi_map_regions(&count);
> - if (!new_memmap) {
> - pr_err("Error reallocating memory, EFI runtime non-functional!\n");
> - return;
> + if (esdata)
> + efi_map_regions_fixed();
> + else {
> + efi_merge_regions();
> + new_memmap = efi_map_regions(&count);
> + if (!new_memmap) {
> + pr_err("Error reallocating memory, EFI runtime non-functional!\n");
> + return;
> + }

CHECK: braces {} should be used on all arms of this statement
#253: FILE: arch/x86/platform/efi/efi.c:1040:
+ if (esdata)
[...]
+ else {
[...]

--
Regards/Gruss,
Boris.

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