On 01/06/16 at 05:50pm, Xunlei Pang wrote:
> diff --git a/arch/x86/kernel/machine_kexec_64.c
> b/arch/x86/kernel/machine_kexec_64.c
> index 819ab3f..cda867d 100644
> --- a/arch/x86/kernel/machine_kexec_64.c
> +++ b/arch/x86/kernel/machine_kexec_64.c
> @@ -536,3 +536,44 @@ 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] */
> + if (!start || !end || start > end)
> + return 0;
Hi, Xunlei.
if (start > end)
return 0;
See the below comment.
> +
> + page = pfn_to_page(start >> PAGE_SHIFT);
> + nr_pages = (end + PAGE_SIZE - start) >> PAGE_SHIFT;
As I commented in last version, it is better to cover the case if the
range from start to end acrosses two pages.
> + 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);
Adding the following if test to test crashk_low_res is better. Then we
do not need to test if start or end is equal to 0 in kexec_mark_range.
if (crashk_low_res.start != crashk_low_res.end) {
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);
> + kexec_mark_range(control + 2 * PAGE_SIZE, crashk_res.end, protect);
I think it is more readable, if we use MACRO KEXEC_CONTROL_PAGE_SIZE,
instead of using 2*PAGE_SIZE directly.
Thanks
Minfei
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