@@ -598,7 +598,6 @@ source kernel/Kconfig.preempt
source kernel/Kconfig.hz
config ARCH_SUPPORTS_DEBUG_PAGEALLOC
- depends on !HIBERNATION
def_bool y
config ARCH_HAS_HOLES_MEMORYMODEL
@@ -235,8 +235,15 @@ 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*/
+ __flush_dcache_area(__mmuoff_text_start,
+ __mmuoff_text_end - __mmuoff_text_start);
+ __flush_dcache_area(__idmap_text_start,
+ __idmap_text_end - __idmap_text_start);
+
+ /* Clean kvm setup code to PoC? */
+ if (el2_reset_needed())
+ __flush_dcache_area(__hyp_idmap_text_start, __hyp_idmap_text_end - __hyp_idmap_text_start);
/*
* Tell the hibernation core that we've just restored
@@ -252,6 +259,32 @@ int swsusp_arch_suspend(void)
return ret;
}
+static void _copy_pte(pte_t *dst_pte, pte_t *src_pte, unsigned long addr)
+{
+ unsigned long pfn = virt_to_pfn(addr);
+
+ if (pte_valid(*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));
+ } else if (debug_pagealloc_enabled()) {
+ /*
+ * debug_pagealloc may have 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.
+ *
+ * Check for mappable memory that gives us a translation
+ * like part of the linear map.
+ */
+ if (pfn_valid(pfn) && pte_pfn(*src_pte) == pfn)
+ set_pte(dst_pte, __pte((pte_val(*src_pte) & ~PTE_RDONLY) | PTE_VALID));
+ }
+}
+
static int copy_pte(pmd_t *dst_pmd, pmd_t *src_pmd, unsigned long start,
unsigned long end)
{
@@ -267,13 +300,7 @@ 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;
@@ -139,4 +139,42 @@ void __kernel_map_pages(struct page *page, int numpages, int enable)
__pgprot(0),
__pgprot(PTE_VALID));
}
-#endif
+#ifdef CONFIG_HIBERNATION
+/*
+ * When built with CONFIG_DEBUG_PAGEALLOC and CONFIG_HIBERNATION, this function
+ * is used to determine if a linear map page has been marked as not-present by
+ * CONFIG_DEBUG_PAGEALLOC. Walk the page table and check the PTE_VALID bit.
+ * This is based on kern_addr_valid(), which almost does what we need.
+ */
+bool kernel_page_present(struct page *page)
+{
+ pgd_t *pgd;
+ pud_t *pud;
+ pmd_t *pmd;
+ pte_t *pte;
+ unsigned long addr = (unsigned long)page_address(page);
+
+ pgd = pgd_offset_k(addr);
+ if (pgd_none(*pgd))
+ return false;
+
+ pud = pud_offset(pgd, addr);
+ if (pud_none(*pud))
+ return false;
+ if (pud_sect(*pud))
+ return true;
+
+ pmd = pmd_offset(pud, addr);
+ if (pmd_none(*pmd))
+ return false;
+ if (pmd_sect(*pmd))
+ return true;
+
+ pte = pte_offset_kernel(pmd, addr);
+ if (pte_none(*pte))
+ return false;
+
+ return pte_valid(*pte);
+}
+#endif /* CONFIG_HIBERNATION */
+#endif /* CONFIG_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 .mmuoff.text 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> --- Change since v1: * Changed cleaning of text_text section to the new mmuoff section. arch/arm64/Kconfig | 1 - arch/arm64/kernel/hibernate.c | 45 ++++++++++++++++++++++++++++++++++--------- arch/arm64/mm/pageattr.c | 40 +++++++++++++++++++++++++++++++++++++- 3 files changed, 75 insertions(+), 11 deletions(-)