x86: kexec_file: remove X86_64 dependency from prepare_elf64_headers()

The code guarded by CONFIG_X86_64 is necessary on some architectures
which have a dedicated kernel mapping outside of linear memory mapping.
(arm64 is among those.)

In this patch, an additional argument, kernel_map, is added to enable/
disable the code removing #ifdef.

Link: http://lkml.kernel.org/r/20180306102303.9063-5-takahiro.akashi@linaro.orgSigned-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
Acked-by: Dave Young <dyoung@redhat.com>
Tested-by: Dave Young <dyoung@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Baoquan He <bhe@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/x86/kernel/crash.c

@@ -348,7 +348,7 @@ static int prepare_elf64_ram_headers_callback(struct resource *res, void *arg)
 	return 0;
 }
 
-static int prepare_elf64_headers(struct crash_elf_data *ced,
+static int prepare_elf64_headers(struct crash_elf_data *ced, bool kernel_map,
 		void **addr, unsigned long *sz)
 {
 	Elf64_Ehdr *ehdr;
@@ -415,8 +415,8 @@ static int prepare_elf64_headers(struct crash_elf_data *ced,
 	phdr->p_filesz = phdr->p_memsz = VMCOREINFO_NOTE_SIZE;
 	(ehdr->e_phnum)++;
 
-#ifdef CONFIG_X86_64
 	/* Prepare PT_LOAD type program header for kernel text region */
+	if (kernel_map) {
 		phdr = (Elf64_Phdr *)bufp;
 		bufp += sizeof(Elf64_Phdr);
 		phdr->p_type = PT_LOAD;
@@ -425,7 +425,7 @@ static int prepare_elf64_headers(struct crash_elf_data *ced,
 		phdr->p_filesz = phdr->p_memsz = _end - _text;
 		phdr->p_offset = phdr->p_paddr = __pa_symbol(_text);
 		(ehdr->e_phnum)++;
-#endif
+	}
 
 	/* Go through all the ranges in cmem->ranges[] and prepare phdr */
 	for (i = 0; i < cmem->nr_ranges; i++) {
@@ -478,7 +478,7 @@ static int prepare_elf_headers(struct kimage *image, void **addr,
 		goto out;
 
 	/* By default prepare 64bit headers */
-	ret =  prepare_elf64_headers(ced, addr, sz);
+	ret =  prepare_elf64_headers(ced, IS_ENABLED(CONFIG_X86_64), addr, sz);
 	if (ret)
 		goto out;