| Message ID | 20190821183204.23576-11-pasha.tatashin@soleen.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | arm64: MMU enabled kexec relocation | expand |
Hi Pavel, On 21/08/2019 19:31, Pavel Tatashin wrote: > Make trans_pgd_create_copy inline with the other functions in > trans_pgd: use the trans_pgd_info argument, and also use the > trans_pgd_create_empty. > > Note, that the functions that are called by trans_pgd_create_copy are > not yet adjusted to be compliant with trans_pgd: they do not yet use > the provided allocator, do not check for generic errors, and do not yet > use the flags in info argument. > diff --git a/arch/arm64/include/asm/trans_pgd.h b/arch/arm64/include/asm/trans_pgd.h > index 26e5a63676b5..f4a5f255d4a7 100644 > --- a/arch/arm64/include/asm/trans_pgd.h > +++ b/arch/arm64/include/asm/trans_pgd.h > @@ -43,7 +43,12 @@ struct trans_pgd_info { > /* Create and empty trans_pgd page table */ > int trans_pgd_create_empty(struct trans_pgd_info *info, pgd_t **trans_pgd); > > -int trans_pgd_create_copy(pgd_t **dst_pgdp, unsigned long start, > +/* > + * Create trans_pgd and copy entries from from_table to trans_pgd in range > + * [start, end) > + */ > +int trans_pgd_create_copy(struct trans_pgd_info *info, pgd_t **trans_pgd, > + pgd_t *from_table, unsigned long start, > unsigned long end); This creates a copy of the linear-map. Why does it need to be told from_table? > diff --git a/arch/arm64/kernel/hibernate.c b/arch/arm64/kernel/hibernate.c > index 8c2641a9bb09..8bb602e91065 100644 > --- a/arch/arm64/kernel/hibernate.c > +++ b/arch/arm64/kernel/hibernate.c > @@ -323,15 +323,42 @@ int swsusp_arch_resume(void) > phys_addr_t phys_hibernate_exit; > void __noreturn (*hibernate_exit)(phys_addr_t, phys_addr_t, void *, > void *, phys_addr_t, phys_addr_t); > + struct trans_pgd_info trans_info = { > + .trans_alloc_page = hibernate_page_alloc, > + .trans_alloc_arg = (void *)GFP_ATOMIC, > + /* > + * Resume will overwrite areas that may be marked read only > + * (code, rodata). Clear the RDONLY bit from the temporary > + * mappings we use during restore. > + */ > + .trans_flags = TRANS_MKWRITE, > + }; > + /* > + * debug_pagealloc will removed the PTE_VALID bit if the page isn't in > + * use by the resume kernel. It may have been in use by the original > + * kernel, in which case we need to put it back in our copy to do the > + * restore. > + * > + * Before marking this entry valid, check the pfn should be mapped. > + */ > + if (debug_pagealloc_enabled()) > + trans_info.trans_flags |= (TRANS_MKVALID | TRANS_CHECKPFN); The debug_pagealloc_enabled() check should be with the code that generates a different entry. Whether the different entry is correct needs to be considered with debug_pagealloc_enabled() in mind. You are making this tricky logic less clear. There is no way the existing code invents an entry for a !pfn_valid() page. With your 'checkpfn' flag, this thing can. You don't need to generalise this for hypothetical users. If kexec needs to create mappings for bogus pages, I'd like to know why. > /* > * Restoring the memory image will overwrite the ttbr1 page tables. > * Create a second copy of just the linear map, and use this when > * restoring. > */ > - rc = trans_pgd_create_copy(&tmp_pg_dir, PAGE_OFFSET, 0); > - if (rc) > + rc = trans_pgd_create_copy(&trans_info, &tmp_pg_dir, init_mm.pgd, > + PAGE_OFFSET, 0); > + if (rc) { > + if (rc == -ENOMEM) > + pr_err("Failed to allocate memory for temporary page tables.\n"); > + else if (rc == -ENXIO) > + pr_err("Tried to set PTE for PFN that does not exist\n"); > goto out; > + } If you think the distinction for this error message is useful, it would be clearer to change it in the current hibernate code before you move it. (_copy_pte() to return an error, instead of silently failing). Done here, this is unrelated noise. I doubt this is specific to kexec. Thanks, James
> > -int trans_pgd_create_copy(pgd_t **dst_pgdp, unsigned long start, > > +/* > > + * Create trans_pgd and copy entries from from_table to trans_pgd in range > > + * [start, end) > > + */ > > +int trans_pgd_create_copy(struct trans_pgd_info *info, pgd_t **trans_pgd, > > + pgd_t *from_table, unsigned long start, > > unsigned long end); > > This creates a copy of the linear-map. Why does it need to be told from_table? This what done as a generic page table entries copy, but I agree, will remove the from_table. > > > > diff --git a/arch/arm64/kernel/hibernate.c b/arch/arm64/kernel/hibernate.c > > index 8c2641a9bb09..8bb602e91065 100644 > > --- a/arch/arm64/kernel/hibernate.c > > +++ b/arch/arm64/kernel/hibernate.c > > @@ -323,15 +323,42 @@ int swsusp_arch_resume(void) > > phys_addr_t phys_hibernate_exit; > > void __noreturn (*hibernate_exit)(phys_addr_t, phys_addr_t, void *, > > void *, phys_addr_t, phys_addr_t); > > + struct trans_pgd_info trans_info = { > > + .trans_alloc_page = hibernate_page_alloc, > > + .trans_alloc_arg = (void *)GFP_ATOMIC, > > + /* > > + * Resume will overwrite areas that may be marked read only > > + * (code, rodata). Clear the RDONLY bit from the temporary > > + * mappings we use during restore. > > + */ > > + .trans_flags = TRANS_MKWRITE, > > + }; > > > > + /* > > + * debug_pagealloc will removed the PTE_VALID bit if the page isn't in > > + * use by the resume kernel. It may have been in use by the original > > + * kernel, in which case we need to put it back in our copy to do the > > + * restore. > > + * > > + * Before marking this entry valid, check the pfn should be mapped. > > + */ > > + if (debug_pagealloc_enabled()) > > + trans_info.trans_flags |= (TRANS_MKVALID | TRANS_CHECKPFN); > > The debug_pagealloc_enabled() check should be with the code that generates a different > entry. Whether the different entry is correct needs to be considered with > debug_pagealloc_enabled() in mind. You are making this tricky logic less clear. > > There is no way the existing code invents an entry for a !pfn_valid() page. With your > 'checkpfn' flag, this thing can. You don't need to generalise this for hypothetical users. Ok > > > If kexec needs to create mappings for bogus pages, I'd like to know why. > It does not. > > > /* > > * Restoring the memory image will overwrite the ttbr1 page tables. > > * Create a second copy of just the linear map, and use this when > > * restoring. > > */ > > - rc = trans_pgd_create_copy(&tmp_pg_dir, PAGE_OFFSET, 0); > > - if (rc) > > + rc = trans_pgd_create_copy(&trans_info, &tmp_pg_dir, init_mm.pgd, > > + PAGE_OFFSET, 0); > > > + if (rc) { > > + if (rc == -ENOMEM) > > + pr_err("Failed to allocate memory for temporary page tables.\n"); > > + else if (rc == -ENXIO) > > + pr_err("Tried to set PTE for PFN that does not exist\n"); > > goto out; > > + } > > If you think the distinction for this error message is useful, it would be clearer to > change it in the current hibernate code before you move it. (_copy_pte() to return an > error, instead of silently failing). Done here, this is unrelated noise. > Ok, will do that.
diff --git a/arch/arm64/include/asm/trans_pgd.h b/arch/arm64/include/asm/trans_pgd.h index 26e5a63676b5..f4a5f255d4a7 100644 --- a/arch/arm64/include/asm/trans_pgd.h +++ b/arch/arm64/include/asm/trans_pgd.h @@ -43,7 +43,12 @@ struct trans_pgd_info { /* Create and empty trans_pgd page table */ int trans_pgd_create_empty(struct trans_pgd_info *info, pgd_t **trans_pgd); -int trans_pgd_create_copy(pgd_t **dst_pgdp, unsigned long start, +/* + * Create trans_pgd and copy entries from from_table to trans_pgd in range + * [start, end) + */ +int trans_pgd_create_copy(struct trans_pgd_info *info, pgd_t **trans_pgd, + pgd_t *from_table, unsigned long start, unsigned long end); /* diff --git a/arch/arm64/kernel/hibernate.c b/arch/arm64/kernel/hibernate.c index 8c2641a9bb09..8bb602e91065 100644 --- a/arch/arm64/kernel/hibernate.c +++ b/arch/arm64/kernel/hibernate.c @@ -323,15 +323,42 @@ int swsusp_arch_resume(void) phys_addr_t phys_hibernate_exit; void __noreturn (*hibernate_exit)(phys_addr_t, phys_addr_t, void *, void *, phys_addr_t, phys_addr_t); + struct trans_pgd_info trans_info = { + .trans_alloc_page = hibernate_page_alloc, + .trans_alloc_arg = (void *)GFP_ATOMIC, + /* + * Resume will overwrite areas that may be marked read only + * (code, rodata). Clear the RDONLY bit from the temporary + * mappings we use during restore. + */ + .trans_flags = TRANS_MKWRITE, + }; + + /* + * debug_pagealloc will removed the PTE_VALID bit if the page isn't in + * use by the resume kernel. It may have been in use by the original + * kernel, in which case we need to put it back in our copy to do the + * restore. + * + * Before marking this entry valid, check the pfn should be mapped. + */ + if (debug_pagealloc_enabled()) + trans_info.trans_flags |= (TRANS_MKVALID | TRANS_CHECKPFN); /* * Restoring the memory image will overwrite the ttbr1 page tables. * Create a second copy of just the linear map, and use this when * restoring. */ - rc = trans_pgd_create_copy(&tmp_pg_dir, PAGE_OFFSET, 0); - if (rc) + rc = trans_pgd_create_copy(&trans_info, &tmp_pg_dir, init_mm.pgd, + PAGE_OFFSET, 0); + if (rc) { + if (rc == -ENOMEM) + pr_err("Failed to allocate memory for temporary page tables.\n"); + else if (rc == -ENXIO) + pr_err("Tried to set PTE for PFN that does not exist\n"); goto out; + } /* * We need a zero page that is zero before & after resume in order to diff --git a/arch/arm64/mm/trans_pgd.c b/arch/arm64/mm/trans_pgd.c index ece797aa1841..7d8734709b61 100644 --- a/arch/arm64/mm/trans_pgd.c +++ b/arch/arm64/mm/trans_pgd.c @@ -176,22 +176,17 @@ int trans_pgd_create_empty(struct trans_pgd_info *info, pgd_t **trans_pgd) return 0; } -int trans_pgd_create_copy(pgd_t **dst_pgdp, unsigned long start, +int trans_pgd_create_copy(struct trans_pgd_info *info, pgd_t **trans_pgd, + pgd_t *from_table, unsigned long start, unsigned long end) { int rc; - pgd_t *trans_pgd = (pgd_t *)get_safe_page(GFP_ATOMIC); - if (!trans_pgd) { - pr_err("Failed to allocate memory for temporary page tables.\n"); - return -ENOMEM; - } - - rc = copy_page_tables(trans_pgd, start, end); - if (!rc) - *dst_pgdp = trans_pgd; + rc = trans_pgd_create_empty(info, trans_pgd); + if (rc) + return rc; - return rc; + return copy_page_tables(*trans_pgd, start, end); } int trans_pgd_map_page(struct trans_pgd_info *info, pgd_t *trans_pgd,
Make trans_pgd_create_copy inline with the other functions in trans_pgd: use the trans_pgd_info argument, and also use the trans_pgd_create_empty. Note, that the functions that are called by trans_pgd_create_copy are not yet adjusted to be compliant with trans_pgd: they do not yet use the provided allocator, do not check for generic errors, and do not yet use the flags in info argument. Signed-off-by: Pavel Tatashin <pasha.tatashin@soleen.com> --- arch/arm64/include/asm/trans_pgd.h | 7 ++++++- arch/arm64/kernel/hibernate.c | 31 ++++++++++++++++++++++++++++-- arch/arm64/mm/trans_pgd.c | 17 ++++++---------- 3 files changed, 41 insertions(+), 14 deletions(-)