linux-kernel - [PATCH v2 07/14] arm64, trans_table: adjust trans_table_create

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Message-Id: <20190817024629.26611-8-pasha.tatashin@soleen.com>
Date:   Fri, 16 Aug 2019 22:46:22 -0400
From:   Pavel Tatashin <pasha.tatashin@...een.com>
To:     pasha.tatashin@...een.com, jmorris@...ei.org, sashal@...nel.org,
        ebiederm@...ssion.com, kexec@...ts.infradead.org,
        linux-kernel@...r.kernel.org, corbet@....net,
        catalin.marinas@....com, will@...nel.org,
        linux-arm-kernel@...ts.infradead.org, marc.zyngier@....com,
        james.morse@....com, vladimir.murzin@....com,
        matthias.bgg@...il.com, bhsharma@...hat.com, linux-mm@...ck.org
Subject: [PATCH v2 07/14] arm64, trans_table: adjust trans_table_create_copy interface

Make trans_table_create_copy inline with the other functions in
trans_table: use the trans_table_info argument, and also use the
trans_table_create_empty.

Note, that the functions that are called by trans_table_create_copy are
not yet adjusted to be compliant with trans_table: 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@...een.com>
---
 arch/arm64/include/asm/trans_table.h |  7 ++++++-
 arch/arm64/kernel/hibernate.c        | 31 ++++++++++++++++++++++++++--
 arch/arm64/mm/trans_table.c          | 17 ++++++---------
 3 files changed, 41 insertions(+), 14 deletions(-)

diff --git a/arch/arm64/include/asm/trans_table.h b/arch/arm64/include/asm/trans_table.h
index 02d3a0333dc9..8c296bd3e10f 100644
--- a/arch/arm64/include/asm/trans_table.h
+++ b/arch/arm64/include/asm/trans_table.h
@@ -44,7 +44,12 @@ struct trans_table_info {
 int trans_table_create_empty(struct trans_table_info *info,
 			     pgd_t **trans_table);
 
-int trans_table_create_copy(pgd_t **dst_pgdp, unsigned long start,
+/*
+ * Create trans table and copy entries from from_table to trans_table in range
+ * [start, end)
+ */
+int trans_table_create_copy(struct trans_table_info *info, pgd_t **trans_table,
+			    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 3a7b362e5a58..6fbaff769c1d 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_table_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_table_create_copy(&tmp_pg_dir, PAGE_OFFSET, 0);
-	if (rc)
+	rc = trans_table_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_table.c b/arch/arm64/mm/trans_table.c
index 6deb35f83118..634293ffb54c 100644
--- a/arch/arm64/mm/trans_table.c
+++ b/arch/arm64/mm/trans_table.c
@@ -176,22 +176,17 @@ int trans_table_create_empty(struct trans_table_info *info, pgd_t **trans_table)
 	return 0;
 }
 
-int trans_table_create_copy(pgd_t **dst_pgdp, unsigned long start,
+int trans_table_create_copy(struct trans_table_info *info, pgd_t **trans_table,
+			    pgd_t *from_table, unsigned long start,
 			    unsigned long end)
 {
 	int rc;
-	pgd_t *trans_table = (pgd_t *)get_safe_page(GFP_ATOMIC);
 
-	if (!trans_table) {
-		pr_err("Failed to allocate memory for temporary page tables.\n");
-		return -ENOMEM;
-	}
-
-	rc = copy_page_tables(trans_table, start, end);
-	if (!rc)
-		*dst_pgdp = trans_table;
+	rc = trans_table_create_empty(info, trans_table);
+	if (rc)
+		return rc;
 
-	return rc;
+	return copy_page_tables(*trans_table, start, end);
 }
 
 int trans_table_map_page(struct trans_table_info *info, pgd_t *trans_table,
-- 
2.22.1