From: Simon Glass <sjg@chromium.org>
Date: Mon, 8 Apr 2019 19:20:49 +0000 (-0600)
Subject: div64: Don't instrument the division function
X-Git-Url: http://git.dujemihanovic.xyz/img/static/git-favicon.png?a=commitdiff_plain;h=f611a46ef1dc70bbbf013d0c33978d1204aeabc5;p=u-boot.git

div64: Don't instrument the division function

This function may be called from tracing code, since that code needs to
read the timer and this often requires calling do_div(), which calls
__div64_32(). If this function is instrumented it causes an infinite loop,
since emitting a trace record requests the time, which in turn emits a
trace record, etc.

Update the prototype to prevent instrumentation code being added.

Signed-off-by: Simon Glass <sjg@chromium.org>
---

diff --git a/lib/div64.c b/lib/div64.c
index 7abc68c333..62933c92c4 100644
--- a/lib/div64.c
+++ b/lib/div64.c
@@ -25,7 +25,13 @@
 #if BITS_PER_LONG == 32
 
 #ifndef __div64_32
-u32 __attribute__((weak)) __div64_32(u64 *n, u32 base)
+/*
+ * Don't instrument this function as it may be called from tracing code, since
+ * it needs to read the timer and this often requires calling do_div(), which
+ * calls this function.
+ */
+uint32_t __attribute__((weak, no_instrument_function)) __div64_32(u64 *n,
+								  u32 base)
 {
 	u64 rem = *n;
 	u64 b = base;