LoongArch: Load vmlinux.efi to the link address

Currently, kexec loads vmlinux.efi to address 0 instead of the link
address. This causes kexec to fail to boot the new vmlinux.efi on qemu.

  pei_loongarch_load: kernel_segment: 0000000000000000
  pei_loongarch_load: kernel_entry:   00000000015dc000
  pei_loongarch_load: image_size:     0000000001f30000
  pei_loongarch_load: text_offset:    0000000000200000
  pei_loongarch_load: phys_offset:    0000000000000000
  pei_loongarch_load: PE format:      yes
  loongarch_load_other_segments:333: command_line: kexec console=ttyS0,115200
  kexec_load: entry = 0x15dc000 flags = 0x1020000
  nr_segments = 2
  segment[0].buf   = 0x7fffef664010
  segment[0].bufsz = 0x1de9a00
  segment[0].mem   = (nil)
  segment[0].memsz = 0x1f30000
  segment[1].buf   = 0x555555e480b0
  segment[1].bufsz = 0x200
  segment[1].mem   = 0x1f30000
  segment[1].memsz = 0x4000

This patch adds `text_offset` when adding kernel segment to load
vmlinux.efi to the link address.

  pei_loongarch_load: kernel_segment: 0000000000000000
  pei_loongarch_load: kernel_entry:   00000000015dc000
  pei_loongarch_load: image_size:     0000000001f30000
  pei_loongarch_load: text_offset:    0000000000200000
  pei_loongarch_load: phys_offset:    0000000000000000
  pei_loongarch_load: PE format:      yes
  loongarch_load_other_segments:335: command_line: kexec console=ttyS0,115200
  kexec_load: entry = 0x15dc000 flags = 0x1020000
  nr_segments = 2
  segment[0].buf   = 0x7ffff1a04010
  segment[0].bufsz = 0x1de9a00
  segment[0].mem   = 0x200000
  segment[0].memsz = 0x1f30000
  segment[1].buf   = 0x555555b28098
  segment[1].bufsz = 0x200
  segment[1].mem   = 0x2130000
  segment[1].memsz = 0x4000

Signed-off-by: WANG Rui <wangrui@loongson.cn>
Signed-off-by: Simon Horman <horms@kernel.org>

kexec/arch/loongarch/kexec-pei-loongarch.c

@@ -87,7 +87,8 @@ int pei_loongarch_load(int argc, char **argv, const char *buf,
 	/* Get kernel entry point */
 	info->entry = (void *)kernel_entry;
 
-	hole_min = kernel_segment + loongarch_mem.image_size;
+	hole_min = kernel_segment + loongarch_mem.text_offset +
+		loongarch_mem.image_size;
 
 	/* Create and initialize elf core header segment */
 	if (info->kexec_flags & KEXEC_ON_CRASH) {
@@ -100,7 +101,8 @@ int pei_loongarch_load(int argc, char **argv, const char *buf,
 	}
 
 	/* Load the kernel */
-	add_segment(info, buf, len, kernel_segment, loongarch_mem.image_size);
+	add_segment(info, buf, len, kernel_segment + loongarch_mem.text_offset,
+				loongarch_mem.image_size);
 
 	/* Prepare and load dtb and initrd data */
 	result = loongarch_load_other_segments(info, hole_min);