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author | Xunlei Pang <xlpang@redhat.com> | 2016-05-23 23:24:13 (GMT) |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2016-05-24 00:04:14 (GMT) |
commit | 1e5768ae7500e7ce6eb73e1b263574d5c19606cf (patch) | |
tree | f1ee8f6df689552e38c926fb2d028a8a5d358b93 /arch/x86/kernel/machine_kexec_64.c | |
parent | 9b492cf58077a0254eb4b9574029ac6e79add9f9 (diff) | |
download | linux-1e5768ae7500e7ce6eb73e1b263574d5c19606cf.tar.xz |
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: Xunlei 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: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch/x86/kernel/machine_kexec_64.c')
-rw-r--r-- | arch/x86/kernel/machine_kexec_64.c | 45 |
1 files changed, 45 insertions, 0 deletions
diff --git a/arch/x86/kernel/machine_kexec_64.c b/arch/x86/kernel/machine_kexec_64.c index ba7fbba..5a294e4 100644 --- a/arch/x86/kernel/machine_kexec_64.c +++ b/arch/x86/kernel/machine_kexec_64.c @@ -538,3 +538,48 @@ overflow: 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); +} |