+ x86-mm-convert-ptdump_walk_pgd_level_core-to-take-an-mm_struct.patch added to -mm tree

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The patch titled
     Subject: x86: mm: convert ptdump_walk_pgd_level_core() to take an mm_struct
has been added to the -mm tree.  Its filename is
     x86-mm-convert-ptdump_walk_pgd_level_core-to-take-an-mm_struct.patch

This patch should soon appear at
    http://ozlabs.org/~akpm/mmots/broken-out/x86-mm-convert-ptdump_walk_pgd_level_core-to-take-an-mm_struct.patch
and later at
    http://ozlabs.org/~akpm/mmotm/broken-out/x86-mm-convert-ptdump_walk_pgd_level_core-to-take-an-mm_struct.patch

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------------------------------------------------------
From: Steven Price <steven.price@xxxxxxx>
Subject: x86: mm: convert ptdump_walk_pgd_level_core() to take an mm_struct

An mm_struct is needed to enable x86 to use of the generic
walk_page_range() function.

In the case of walking the user page tables (when
CONFIG_PAGE_TABLE_ISOLATION is enabled), it is necessary to create a
fake_mm structure because there isn't an mm_struct with a pointer to the
pgd of the user page tables.  This fake_mm structure is initialised with
the minimum necessary for the generic page walk code.

Link: http://lkml.kernel.org/r/20190722154210.42799-19-steven.price@xxxxxxx
Signed-off-by: Steven Price <steven.price@xxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---

 arch/x86/mm/dump_pagetables.c |   36 ++++++++++++++++++--------------
 1 file changed, 21 insertions(+), 15 deletions(-)

--- a/arch/x86/mm/dump_pagetables.c~x86-mm-convert-ptdump_walk_pgd_level_core-to-take-an-mm_struct
+++ a/arch/x86/mm/dump_pagetables.c
@@ -107,8 +107,6 @@ static struct addr_marker address_marker
 	[END_OF_SPACE_NR]	= { -1,			NULL }
 };
 
-#define INIT_PGD	((pgd_t *) &init_top_pgt)
-
 #else /* CONFIG_X86_64 */
 
 enum address_markers_idx {
@@ -143,8 +141,6 @@ static struct addr_marker address_marker
 	[END_OF_SPACE_NR]	= { -1,			NULL }
 };
 
-#define INIT_PGD	(swapper_pg_dir)
-
 #endif /* !CONFIG_X86_64 */
 
 /* Multipliers for offsets within the PTEs */
@@ -516,10 +512,10 @@ static inline bool is_hypervisor_range(i
 #endif
 }
 
-static void ptdump_walk_pgd_level_core(struct seq_file *m, pgd_t *pgd,
+static void ptdump_walk_pgd_level_core(struct seq_file *m, struct mm_struct *mm,
 				       bool checkwx, bool dmesg)
 {
-	pgd_t *start = pgd;
+	pgd_t *start = mm->pgd;
 	pgprotval_t prot, eff;
 	int i;
 	struct pg_state st = {};
@@ -566,39 +562,49 @@ static void ptdump_walk_pgd_level_core(s
 
 void ptdump_walk_pgd_level(struct seq_file *m, struct mm_struct *mm)
 {
-	ptdump_walk_pgd_level_core(m, mm->pgd, false, true);
+	ptdump_walk_pgd_level_core(m, mm, false, true);
+}
+
+#ifdef CONFIG_PAGE_TABLE_ISOLATION
+static void ptdump_walk_pgd_level_user_core(struct seq_file *m,
+					    struct mm_struct *mm,
+					    bool checkwx, bool dmesg)
+{
+	struct mm_struct fake_mm = {
+		.pgd = kernel_to_user_pgdp(mm->pgd)
+	};
+	init_rwsem(&fake_mm.mmap_sem);
+	ptdump_walk_pgd_level_core(m, &fake_mm, checkwx, dmesg);
 }
+#endif
 
 void ptdump_walk_pgd_level_debugfs(struct seq_file *m, struct mm_struct *mm,
 				   bool user)
 {
-	pgd_t *pgd = mm->pgd;
 #ifdef CONFIG_PAGE_TABLE_ISOLATION
 	if (user && boot_cpu_has(X86_FEATURE_PTI))
-		pgd = kernel_to_user_pgdp(pgd);
+		ptdump_walk_pgd_level_user_core(m, mm, false, false);
+	else
 #endif
-	ptdump_walk_pgd_level_core(m, pgd, false, false);
+		ptdump_walk_pgd_level_core(m, mm, false, false);
 }
 EXPORT_SYMBOL_GPL(ptdump_walk_pgd_level_debugfs);
 
 void ptdump_walk_user_pgd_level_checkwx(void)
 {
 #ifdef CONFIG_PAGE_TABLE_ISOLATION
-	pgd_t *pgd = INIT_PGD;
-
 	if (!(__supported_pte_mask & _PAGE_NX) ||
 	    !boot_cpu_has(X86_FEATURE_PTI))
 		return;
 
 	pr_info("x86/mm: Checking user space page tables\n");
-	pgd = kernel_to_user_pgdp(pgd);
-	ptdump_walk_pgd_level_core(NULL, pgd, true, false);
+	ptdump_walk_pgd_level_user_core(NULL, &init_mm, true, false);
 #endif
 }
 
 void ptdump_walk_pgd_level_checkwx(void)
 {
-	ptdump_walk_pgd_level_core(NULL, INIT_PGD, true, false);
+	ptdump_walk_pgd_level_core(NULL, &init_mm, true, false);
 }
 
 static int __init pt_dump_init(void)
_

Patches currently in -mm which might be from steven.price@xxxxxxx are

arc-mm-add-pd_leaf-definitions.patch
arm-mm-add-pd_leaf-definitions.patch
arm64-mm-add-pd_leaf-definitions.patch
mips-mm-add-pd_leaf-definitions.patch
powerpc-mm-add-pd_leaf-definitions.patch
riscv-mm-add-pd_leaf-definitions.patch
s390-mm-add-pd_leaf-definitions.patch
sparc-mm-add-pd_leaf-definitions.patch
x86-mm-add-pd_leaf-definitions.patch
mm-add-generic-pd_leaf-macros.patch
mm-pagewalk-add-p4d_entry-and-pgd_entry.patch
mm-pagewalk-allow-walking-without-vma.patch
mm-pagewalk-add-test_pd-callbacks.patch
x86-mm-dont-display-pages-which-arent-present-in-debugfs.patch
x86-mm-point-to-struct-seq_file-from-struct-pg_state.patch
x86-mmefi-convert-ptdump_walk_pgd_level-to-take-a-mm_struct.patch
x86-mm-convert-ptdump_walk_pgd_level_debugfs-to-take-an-mm_struct.patch
x86-mm-convert-ptdump_walk_pgd_level_core-to-take-an-mm_struct.patch
mm-add-generic-ptdump.patch
x86-mm-convert-dump_pagetables-to-use-walk_page_range.patch
arm64-mm-convert-mm-dumpc-to-use-walk_page_range.patch




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