[PATCH 02/11] mm: debug: deal with a new family of MM pointers

From: Sasha Levin
Date: Thu May 14 2015 - 13:12:37 EST


This teaches our printing functions about a new family of MM pointer that it
could now print.

I've picked %pZ because %pm and %pM were already taken, so I figured it
doesn't really matter what we go with. We also have the option of stealing
one of those two...

Signed-off-by: Sasha Levin <sasha.levin@xxxxxxxxxx>
---
lib/vsprintf.c | 18 ++++++++++++++++++
1 file changed, 18 insertions(+)

diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index 8243e2f..9350904 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -1375,6 +1375,21 @@ char *comm_name(char *buf, char *end, struct task_struct *tsk,
return string(buf, end, name, spec);
}

+static noinline_for_stack
+char *mm_pointer(char *buf, char *end, struct task_struct *tsk,
+ struct printf_spec spec, const char *fmt)
+{
+ switch (fmt[1]) {
+ default:
+ spec.base = 16;
+ spec.field_width = sizeof(unsigned long) * 2 + 2;
+ spec.flags |= SPECIAL | SMALL | ZEROPAD;
+ return number(buf, end, (unsigned long) ptr, spec);
+ }
+
+ return buf;
+}
+
int kptr_restrict __read_mostly;

/*
@@ -1463,6 +1478,7 @@ int kptr_restrict __read_mostly;
* (legacy clock framework) of the clock
* - 'Cr' For a clock, it prints the current rate of the clock
* - 'T' task_struct->comm
+ * - 'Z' Outputs a readable version of a type of memory management struct.
*
* Note: The difference between 'S' and 'F' is that on ia64 and ppc64
* function pointers are really function descriptors, which contain a
@@ -1615,6 +1631,8 @@ char *pointer(const char *fmt, char *buf, char *end, void *ptr,
spec, fmt);
case 'T':
return comm_name(buf, end, ptr, spec, fmt);
+ case 'Z':
+ return mm_pointer(buf, end, ptr, spec, fmt);
}
spec.flags |= SMALL;
if (spec.field_width == -1) {
--
1.7.10.4

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