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authorThomas Gleixner <tglx@linutronix.de>2017-12-04 15:08:06 +0100
committerIngo Molnar <mingo@kernel.org>2017-12-23 21:13:01 +0100
commita4b51ef6552c704764684cef7e753162dc87c5fa (patch)
treee94c41819a8e73e897e296d6406a790d78579f65 /arch
parentb4bf4f924b1d7bade38fd51b2e401d20d0956e4d (diff)
downloadlinux-a4b51ef6552c704764684cef7e753162dc87c5fa.tar.bz2
x86/mm/dump_pagetables: Allow dumping current pagetables
Add two debugfs files which allow to dump the pagetable of the current task. current_kernel dumps the regular page table. This is the page table which is normally shared between kernel and user space. If kernel page table isolation is enabled this is the kernel space mapping. If kernel page table isolation is enabled the second file, current_user, dumps the user space page table. These files allow to verify the resulting page tables for page table isolation, but even in the normal case its useful to be able to inspect user space page tables of current for debugging purposes. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Andy Lutomirski <luto@kernel.org> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: David Laight <David.Laight@aculab.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Eduardo Valentin <eduval@amazon.com> Cc: Greg KH <gregkh@linuxfoundation.org> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Juergen Gross <jgross@suse.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Will Deacon <will.deacon@arm.com> Cc: aliguori@amazon.com Cc: daniel.gruss@iaik.tugraz.at Cc: hughd@google.com Cc: keescook@google.com Cc: linux-mm@kvack.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/include/asm/pgtable.h2
-rw-r--r--arch/x86/mm/debug_pagetables.c71
-rw-r--r--arch/x86/mm/dump_pagetables.c6
3 files changed, 73 insertions, 6 deletions
diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
index 03780d5c41c5..6b43d677f8ca 100644
--- a/arch/x86/include/asm/pgtable.h
+++ b/arch/x86/include/asm/pgtable.h
@@ -28,7 +28,7 @@ extern pgd_t early_top_pgt[PTRS_PER_PGD];
int __init __early_make_pgtable(unsigned long address, pmdval_t pmd);
void ptdump_walk_pgd_level(struct seq_file *m, pgd_t *pgd);
-void ptdump_walk_pgd_level_debugfs(struct seq_file *m, pgd_t *pgd);
+void ptdump_walk_pgd_level_debugfs(struct seq_file *m, pgd_t *pgd, bool user);
void ptdump_walk_pgd_level_checkwx(void);
#ifdef CONFIG_DEBUG_WX
diff --git a/arch/x86/mm/debug_pagetables.c b/arch/x86/mm/debug_pagetables.c
index 8e70c1599e51..421f2664ffa0 100644
--- a/arch/x86/mm/debug_pagetables.c
+++ b/arch/x86/mm/debug_pagetables.c
@@ -5,7 +5,7 @@
static int ptdump_show(struct seq_file *m, void *v)
{
- ptdump_walk_pgd_level_debugfs(m, NULL);
+ ptdump_walk_pgd_level_debugfs(m, NULL, false);
return 0;
}
@@ -22,7 +22,57 @@ static const struct file_operations ptdump_fops = {
.release = single_release,
};
-static struct dentry *dir, *pe;
+static int ptdump_show_curknl(struct seq_file *m, void *v)
+{
+ if (current->mm->pgd) {
+ down_read(&current->mm->mmap_sem);
+ ptdump_walk_pgd_level_debugfs(m, current->mm->pgd, false);
+ up_read(&current->mm->mmap_sem);
+ }
+ return 0;
+}
+
+static int ptdump_open_curknl(struct inode *inode, struct file *filp)
+{
+ return single_open(filp, ptdump_show_curknl, NULL);
+}
+
+static const struct file_operations ptdump_curknl_fops = {
+ .owner = THIS_MODULE,
+ .open = ptdump_open_curknl,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = single_release,
+};
+
+#ifdef CONFIG_PAGE_TABLE_ISOLATION
+static struct dentry *pe_curusr;
+
+static int ptdump_show_curusr(struct seq_file *m, void *v)
+{
+ if (current->mm->pgd) {
+ down_read(&current->mm->mmap_sem);
+ ptdump_walk_pgd_level_debugfs(m, current->mm->pgd, true);
+ up_read(&current->mm->mmap_sem);
+ }
+ return 0;
+}
+
+static int ptdump_open_curusr(struct inode *inode, struct file *filp)
+{
+ return single_open(filp, ptdump_show_curusr, NULL);
+}
+
+static const struct file_operations ptdump_curusr_fops = {
+ .owner = THIS_MODULE,
+ .open = ptdump_open_curusr,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = single_release,
+};
+#endif
+
+static struct dentry *dir, *pe_knl, *pe_curknl;
static int __init pt_dump_debug_init(void)
{
@@ -30,9 +80,22 @@ static int __init pt_dump_debug_init(void)
if (!dir)
return -ENOMEM;
- pe = debugfs_create_file("kernel", 0400, dir, NULL, &ptdump_fops);
- if (!pe)
+ pe_knl = debugfs_create_file("kernel", 0400, dir, NULL,
+ &ptdump_fops);
+ if (!pe_knl)
+ goto err;
+
+ pe_curknl = debugfs_create_file("current_kernel", 0400,
+ dir, NULL, &ptdump_curknl_fops);
+ if (!pe_curknl)
+ goto err;
+
+#ifdef CONFIG_PAGE_TABLE_ISOLATION
+ pe_curusr = debugfs_create_file("current_user", 0400,
+ dir, NULL, &ptdump_curusr_fops);
+ if (!pe_curusr)
goto err;
+#endif
return 0;
err:
debugfs_remove_recursive(dir);
diff --git a/arch/x86/mm/dump_pagetables.c b/arch/x86/mm/dump_pagetables.c
index 17f5b417f95e..f56902c1f04b 100644
--- a/arch/x86/mm/dump_pagetables.c
+++ b/arch/x86/mm/dump_pagetables.c
@@ -530,8 +530,12 @@ void ptdump_walk_pgd_level(struct seq_file *m, pgd_t *pgd)
ptdump_walk_pgd_level_core(m, pgd, false, true);
}
-void ptdump_walk_pgd_level_debugfs(struct seq_file *m, pgd_t *pgd)
+void ptdump_walk_pgd_level_debugfs(struct seq_file *m, pgd_t *pgd, bool user)
{
+#ifdef CONFIG_PAGE_TABLE_ISOLATION
+ if (user && static_cpu_has(X86_FEATURE_PTI))
+ pgd = kernel_to_user_pgdp(pgd);
+#endif
ptdump_walk_pgd_level_core(m, pgd, false, false);
}
EXPORT_SYMBOL_GPL(ptdump_walk_pgd_level_debugfs);