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Commit 1e5768ae authored by Xunlei Pang's avatar Xunlei Pang Committed by Linus Torvalds
Browse files

kexec: provide arch_kexec_protect(unprotect)_crashkres() 



Implement the protection method for the crash kernel memory reservation
for the 64-bit x86 kdump.

Signed-off-by: default avatarXunlei Pang <xlpang@redhat.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Minfei Huang <mhuang@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Baoquan He <bhe@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 9b492cf5

arch/x86/kernel/machine_kexec_64.c

+45 −0
Original line number Diff line number Diff line
@@ -538,3 +538,48 @@ int arch_kexec_apply_relocations_add(const Elf64_Ehdr *ehdr, 
	return -ENOEXEC;

}

#endif /* CONFIG_KEXEC_FILE */



static int

kexec_mark_range(unsigned long start, unsigned long end, bool protect)

{

	struct page *page;

	unsigned int nr_pages;



	/*

	 * For physical range: [start, end]. We must skip the unassigned

	 * crashk resource with zero-valued "end" member.

	 */

	if (!end || start > end)

		return 0;



	page = pfn_to_page(start >> PAGE_SHIFT);

	nr_pages = (end >> PAGE_SHIFT) - (start >> PAGE_SHIFT) + 1;

	if (protect)

		return set_pages_ro(page, nr_pages);

	else

		return set_pages_rw(page, nr_pages);

}



static void kexec_mark_crashkres(bool protect)

{

	unsigned long control;



	kexec_mark_range(crashk_low_res.start, crashk_low_res.end, protect);



	/* Don't touch the control code page used in crash_kexec().*/

	control = PFN_PHYS(page_to_pfn(kexec_crash_image->control_code_page));

	/* Control code page is located in the 2nd page. */

	kexec_mark_range(crashk_res.start, control + PAGE_SIZE - 1, protect);

	control += KEXEC_CONTROL_PAGE_SIZE;

	kexec_mark_range(control, crashk_res.end, protect);

}



void arch_kexec_protect_crashkres(void)

{

	kexec_mark_crashkres(true);

}



void arch_kexec_unprotect_crashkres(void)

{

	kexec_mark_crashkres(false);

}