Hi Pavel,
On 26/03/2020 03:24, Pavel Tatashin wrote:
> kexec is going to use a different allocator, so make
> trans_pgd_map_page to accept allocator as an argument, and also
> kexec is going to use a different map protection, so also pass
> it via argument.
This trans_pgd_map_page() used to be create_single_mapping() It creates page tables that
map one page: the relocation code.
Why do you need a different pgprot? Surely PAGE_KERNEL_EXEC is exactly what you want.
> diff --git a/arch/arm64/include/asm/trans_pgd.h b/arch/arm64/include/asm/trans_pgd.h
> index 23153c13d1ce..ad5194ad178d 100644
> --- a/arch/arm64/include/asm/trans_pgd.h
> +++ b/arch/arm64/include/asm/trans_pgd.h
> @@ -12,10 +12,24 @@
> #include <linux/types.h>
> #include <asm/pgtable-types.h>
>
> +/*
> + * trans_alloc_page
> + * - Allocator that should return exactly one zeroed page, if this
> + * allocator fails, trans_pgd returns -ENOMEM error.
trans_pgd is what you pass in to trans_pgd_map_page() or trans_pgd_create_copy().
Do you mean what those functions return?
> + *
> + * trans_alloc_arg
> + * - Passed to trans_alloc_page as an argument
> + */
> diff --git a/arch/arm64/kernel/hibernate.c b/arch/arm64/kernel/hibernate.c
> index 3d6f0fd73591..607bb1fbc349 100644
> --- a/arch/arm64/kernel/hibernate.c
> +++ b/arch/arm64/kernel/hibernate.c
> @@ -195,6 +200,11 @@ static int create_safe_exec_page(void *src_start, size_t length,
> unsigned long dst_addr,
> phys_addr_t *phys_dst_addr)
> {
> + struct trans_pgd_info trans_info = {
> + .trans_alloc_page = hibernate_page_alloc,
> + .trans_alloc_arg = (void *)GFP_ATOMIC,
> + };
As you need another copy of this in the next patch, is it worth declaring this globally
and making it const?
> diff --git a/arch/arm64/mm/trans_pgd.c b/arch/arm64/mm/trans_pgd.c
> index d20e48520cef..275a79935d7e 100644
> --- a/arch/arm64/mm/trans_pgd.c
> +++ b/arch/arm64/mm/trans_pgd.c
> @@ -180,8 +185,18 @@ int trans_pgd_create_copy(pgd_t **dst_pgdp, unsigned long start,
> return rc;
> }
>
> -int trans_pgd_map_page(pgd_t *trans_pgd, void *page, unsigned long dst_addr,
> - pgprot_t pgprot)
> +/*
> + * Add map entry to trans_pgd for a base-size page at PTE level.
> + * info: contains allocator and its argument
> + * trans_pgd: page table in which new map is added.
> + * page: page to be mapped.
> + * dst_addr: new VA address for the pages
~s/pages/page/
This thing only maps one page.
> + * pgprot: protection for the page.
> + *
> + * Returns 0 on success, and -ENOMEM on failure.
> + */
> +int trans_pgd_map_page(struct trans_pgd_info *info, pgd_t *trans_pgd,
> + void *page, unsigned long dst_addr, pgprot_t pgprot)
> {
> pgd_t *pgdp;
> pud_t *pudp;
Thanks,
James
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