Add a new format for printing page table entries.
Cc: Petr Mladek <pmladek@xxxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Cc: Jonathan Corbet <corbet@xxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: linux-doc@xxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
Cc: linux-mm@xxxxxxxxx
Signed-off-by: Anshuman Khandual <anshuman.khandual@xxxxxxx>
---
Documentation/core-api/printk-formats.rst | 14 ++++++++++++++
lib/vsprintf.c | 20 ++++++++++++++++++++
mm/memory.c | 5 ++---
scripts/checkpatch.pl | 2 +-
4 files changed, 37 insertions(+), 4 deletions(-)
diff --git a/Documentation/core-api/printk-formats.rst b/Documentation/core-api/printk-formats.rst
index 4b7f3646ec6ce..75a110b059ee1 100644
--- a/Documentation/core-api/printk-formats.rst
+++ b/Documentation/core-api/printk-formats.rst
@@ -689,6 +689,20 @@ Rust
Only intended to be used from Rust code to format ``core::fmt::Arguments``.
Do *not* use it from C.
+Page Table Entry
+----------------
+
+::
+ %ppte
+
+Print standard page table entry pte_t.
+
+Passed by reference.
+
+Examples for a 64 bit page table entry, given &(u64)0xc0ffee::
+
+ %ppte 0x00c0ffee
+
Thanks
======
diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index 3d85800757aa5..005490202ffb5 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -2433,6 +2433,9 @@ early_param("no_hash_pointers", no_hash_pointers_enable);
* Without an option prints the full name of the node
* f full name
* P node name, including a possible unit address
+ * - 'pte' For a 64 bit page table entry, this prints its contents in
+ * a hexa decimal format
+ *
* - 'x' For printing the address unmodified. Equivalent to "%lx".
* Please read the documentation (path below) before using!
* - '[ku]s' For a BPF/tracing related format specifier, e.g. used out of
@@ -2542,6 +2545,23 @@ char *pointer(const char *fmt, char *buf, char *end, void *ptr,
default:
return error_string(buf, end, "(einval)", spec);
}
+ case 'p':
+ if (fmt[1] == 't' && fmt[2] == 'e') {
+ pte_t *pte = (pte_t *)ptr;
+
+ spec.field_width = 10;
+ spec.precision = 8;
+ spec.base = 16;
+ spec.flags = SPECIAL | SMALL | ZEROPAD;
+ if (sizeof(pte_t) == sizeof(u64)) {
+ u64 val = pte_val(*pte);
+
+ return number(buf, end, val, spec);
+ }
+ WARN_ONCE(1, "Non standard pte_t\n");
+ return error_string(buf, end, "(einval)", spec);
+ }
+ fallthrough;
default:
return default_pointer(buf, end, ptr, spec);
}
diff --git a/mm/memory.c b/mm/memory.c
index 8eba595056fe3..c9a057b371eae 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -522,9 +522,8 @@ static void print_bad_pte(struct vm_area_struct *vma, unsigned long addr,
mapping = vma->vm_file ? vma->vm_file->f_mapping : NULL;
index = linear_page_index(vma, addr);
- pr_alert("BUG: Bad page map in process %s pte:%08llx pmd:%08llx\n",
- current->comm,
- (long long)pte_val(pte), (long long)pmd_val(*pmd));
+ pr_alert("BUG: Bad page map in process %s pte:%ppte pmd:%ppte\n",
+ current->comm, &pte, pmd);
if (page)
dump_page(page, "bad pte");
pr_alert("addr:%px vm_flags:%08lx anon_vma:%px mapping:%px index:%lx\n",
diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 664f7b7a622c2..fb8abc5dbfb8e 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -6906,7 +6906,7 @@ sub process {
my $fmt = get_quoted_string($lines[$count - 1], raw_line($count, 0));
$fmt =~ s/%%//g;
- while ($fmt =~ /(\%[\*\d\.]*p(\w)(\w*))/g) {
+ while ($fmt =~ /(\%[\*\d\.]*p(\w)(\w*)(\te))/g) {
$specifier = $1;
$extension = $2;
$qualifier = $3;
--
2.30.2
