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author | James Morse <james.morse@arm.com> | 2016-08-24 18:27:30 +0100 |
---|---|---|
committer | Will Deacon <will.deacon@arm.com> | 2016-08-25 18:00:30 +0100 |
commit | 5ebe3a44cc744d11cb60d8438106a9322b7c04dc (patch) | |
tree | 24cc917fb9078acdc2b1deee131c4744d625cf1e /arch/arm64/kernel/hibernate.c | |
parent | b61130381120398876b86282082ad9f24976dfcf (diff) | |
download | linux-5ebe3a44cc744d11cb60d8438106a9322b7c04dc.tar.bz2 |
arm64: hibernate: Support DEBUG_PAGEALLOC
DEBUG_PAGEALLOC removes the valid bit of page table entries to prevent
any access to unallocated memory. Hibernate uses this as a hint that those
pages don't need to be saved/restored. This patch adds the
kernel_page_present() function it uses.
hibernate.c copies the resume kernel's linear map for use during restore.
Add _copy_pte() to fill-in the holes made by DEBUG_PAGEALLOC in the resume
kernel, so we can restore data the original kernel had at these addresses.
Finally, DEBUG_PAGEALLOC means the linear-map alias of KERNEL_START to
KERNEL_END may have holes in it, so we can't lazily clean this whole
area to the PoC. Only clean the new mmuoff region, and the kernel/kvm
idmaps.
This reverts commit da24eb1f3f9e2c7b75c5f8c40d8e48e2c4789596.
Reported-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: James Morse <james.morse@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Diffstat (limited to 'arch/arm64/kernel/hibernate.c')
-rw-r--r-- | arch/arm64/kernel/hibernate.c | 45 |
1 files changed, 36 insertions, 9 deletions
diff --git a/arch/arm64/kernel/hibernate.c b/arch/arm64/kernel/hibernate.c index b4082017c4cb..71d82cfb62f5 100644 --- a/arch/arm64/kernel/hibernate.c +++ b/arch/arm64/kernel/hibernate.c @@ -235,6 +235,7 @@ out: return rc; } +#define dcache_clean_range(start, end) __flush_dcache_area(start, (end - start)) int swsusp_arch_suspend(void) { @@ -252,8 +253,13 @@ int swsusp_arch_suspend(void) if (__cpu_suspend_enter(&state)) { ret = swsusp_save(); } else { - /* Clean kernel to PoC for secondary core startup */ - __flush_dcache_area(LMADDR(KERNEL_START), KERNEL_END - KERNEL_START); + /* Clean kernel core startup/idle code to PoC*/ + dcache_clean_range(__mmuoff_data_start, __mmuoff_data_end); + dcache_clean_range(__idmap_text_start, __idmap_text_end); + + /* Clean kvm setup code to PoC? */ + if (el2_reset_needed()) + dcache_clean_range(__hyp_idmap_text_start, __hyp_idmap_text_end); /* * Tell the hibernation core that we've just restored @@ -269,6 +275,33 @@ int swsusp_arch_suspend(void) return ret; } +static void _copy_pte(pte_t *dst_pte, pte_t *src_pte, unsigned long addr) +{ + pte_t pte = *src_pte; + + if (pte_valid(pte)) { + /* + * Resume will overwrite areas that may be marked + * read only (code, rodata). Clear the RDONLY bit from + * the temporary mappings we use during restore. + */ + set_pte(dst_pte, pte_clear_rdonly(pte)); + } else if (debug_pagealloc_enabled() && !pte_none(pte)) { + /* + * 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. + */ + BUG_ON(!pfn_valid(pte_pfn(pte))); + + set_pte(dst_pte, pte_mkpresent(pte_clear_rdonly(pte))); + } +} + static int copy_pte(pmd_t *dst_pmd, pmd_t *src_pmd, unsigned long start, unsigned long end) { @@ -284,13 +317,7 @@ static int copy_pte(pmd_t *dst_pmd, pmd_t *src_pmd, unsigned long start, src_pte = pte_offset_kernel(src_pmd, start); do { - if (!pte_none(*src_pte)) - /* - * Resume will overwrite areas that may be marked - * read only (code, rodata). Clear the RDONLY bit from - * the temporary mappings we use during restore. - */ - set_pte(dst_pte, __pte(pte_val(*src_pte) & ~PTE_RDONLY)); + _copy_pte(dst_pte, src_pte, addr); } while (dst_pte++, src_pte++, addr += PAGE_SIZE, addr != end); return 0; |