efi: export efi runtime memory mapping to sysfs

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 directory /sys/firmware/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

Matt: s/efi-runtime-map.c/runtime-map.c
      change dir name to runtime-map
update to use desc_size in efi_runtime_map
cleaup the code, add function efi_save_runtime_map
improve err handling

Matt: changelog fix;
      Documentation fixes.
Add macros for sysfs _show functions
move functions to front of .c, remove forward declarations.

Signed-off-by: Dave Young <dyoung@redhat.com>
efi: passing kexec necessary efi data via setup_data

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, 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 efi_setup
v5: improve some code structure per comments from Matt

Signed-off-by: Dave Young <dyoung@redhat.com>
efi: only print saved efi runtime maps instead of all memmap ranges for kexec

For kexec/kdump kernel efi runtime mappings are saved, printing original whole
memmap ranges does not make sense anymore. So introduce a new function to only
print runtime maps in case kexec/kdump kernel is used.

v2: use efi_setup instead of esdata

Signed-off-by: Dave Young <dyoung@redhat.com>
x86: add xloadflags bit for efi runtime support on kexec

Old kexec-tools can not load new kernel. The reason is previously kexec-tools
do not fill efi_info in x86 setup header thus efi init fail and switch
to noefi boot. In new kexec-tools it will by default fill efi_info and
pass other efi required infomation to 2nd kernel so kexec kernel efi
initialization will success finally.

To prevent from breaking userspace, add a new xloadflags bit so kexec-tools
will check the flag and switch to old logic.

changelog:
Matt: +&& defined(CONFIG_KEXEC)
HPA: document the flag.

Signed-off-by: Dave Young <dyoung@redhat.com>
x86: export x86 boot_params to sysfs

kexec-tools use boot_params for getting the 1st kernel hardware_subarch,
the kexec kernel efi runtime support also need read the old efi_info from
boot_params. Currently it exists in debugfs which is not a good place for
such infomation. Per HPA, we should avoid of "sploit debugfs".

In this patch /sys/kernel/boot_params are exported, also the setup_data
is exported as a subdirectory. For original debugfs since it's already
there for long time and kexec-tools is using it for hardware_subarch so
let's do not remove them for now.

Structure are like below:

/sys/kernel/boot_params
|__ data                /* binary data for boot_params */
|__ setup_data          /* subdirectory for setup_data if there's any */
|   |__ 0               /* the first setup_data node */
|   |   |__ data        /* binary data for setup_data node 0 */
|   |   |__ type        /* setup_data type of setup_data node 0, hex string */
[snip]
|__ version             /* hex string for boot protocal version */

Changelog:
Greg: use __ATTR_RO() and group attr.

Signed-off-by: Dave Young <dyoung@redhat.com>
x86: reserve setup_data ranges late after parsing memmap cmdline

Kdump kernel using memmap=exactmap, move e820_reserve_setup_data after
parsing early params so they can be set reserved finally. Or kdump kernel
will warn about ioremap a normal ram range.

Signed-off-by: Dave Young <dyoung@redhat.com>
x86: kdebugfs do not use __va for getting setup_data virt addr

__va does not work in case memmap=exactmap, so let's always use ioremap_cache.

Signed-off-by: Dave Young <dyoung@redhat.com>