kexec: support kexec/kdump on EFI systems

This patch does two things.  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.

[akpm@linux-foundation.org: s/get_efi/efi_get/g, per Matt]
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>
Cc: Greg Kroah-Hartman <greg@kroah.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: WANG Chao <chaowang@redhat.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Matt Fleming <matt@console-pimps.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 21 insertions, 0 deletions

diff --git a/drivers/firmware/efi/runtime-map.c b/drivers/firmware/efi/runtime-map.c
index 97cdd16a2169..018c29a26615 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 efi_get_runtime_map_size(void)
+{
+        return nr_efi_runtime_map * efi_memdesc_size;
+}
+
+int efi_get_runtime_map_desc_size(void)
+{
+        return efi_memdesc_size;
+}
+
+int efi_runtime_map_copy(void *buf, size_t bufsz)
+{
+        size_t sz = efi_get_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;