Module Name: src
Committed By: rin
Date: Fri May 6 04:49:13 UTC 2022
Modified Files:
src/lib/libc/gmon: gmon.c
Log Message:
PR lib/56395
PR toolchain/56771
Fix profiling on CPUs that do not support unaligned memory access;
Allocate objects (referenced from struct gmonparam) with proper
alignments.
For monstartup(), objects are allocated on heap. Break is not
guaranteed to be aligned at all, unlike stack pointer.
For _m_gmon_alloc(), objects are allocated on anonymous memory.
p->tos is not aligned properly in general.
This fixes quasi-random crashes for *_profile tests, at least on
SH-4 and PowerPC 403 [1]. Also, no regression is observed for
others as far as I can see.
This change does not cause any ABI breakage, as long as application
uses proper pointers; use p->tos instead of evil pointer arithmetic
like (struct tostruct *)((char *)p->froms + p->fromssize) [2].
[1] Timeout should be increased for some tests. "pic" variants
still fail as expected. Dynamically-linked binaries also crash in
rtld for SH-4, but this seems different problem...
[2] This example did not work even before, since the order of
froms[] and tos[] is reversed depending on which of monstartup() or
_m_gmon_alloc() is used for allocation.
To generate a diff of this commit:
cvs rdiff -u -r1.36 -r1.37 src/lib/libc/gmon/gmon.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/lib/libc/gmon/gmon.c
diff -u src/lib/libc/gmon/gmon.c:1.36 src/lib/libc/gmon/gmon.c:1.37
--- src/lib/libc/gmon/gmon.c:1.36 Sat Jul 3 14:08:55 2021
+++ src/lib/libc/gmon/gmon.c Fri May 6 04:49:13 2022
@@ -1,4 +1,4 @@
-/* $NetBSD: gmon.c,v 1.36 2021/07/03 14:08:55 christos Exp $ */
+/* $NetBSD: gmon.c,v 1.37 2022/05/06 04:49:13 rin Exp $ */
/*
* Copyright (c) 2003, 2004 Wasabi Systems, Inc.
@@ -69,7 +69,7 @@
#if 0
static char sccsid[] = "@(#)gmon.c 8.1 (Berkeley) 6/4/93";
#else
-__RCSID("$NetBSD: gmon.c,v 1.36 2021/07/03 14:08:55 christos Exp $");
+__RCSID("$NetBSD: gmon.c,v 1.37 2022/05/06 04:49:13 rin Exp $");
#endif
#endif
@@ -141,21 +141,25 @@ monstartup(u_long lowpc, u_long highpc)
p->tolimit = MAXARCS;
p->tossize = p->tolimit * sizeof(struct tostruct);
- cp = sbrk((intptr_t)(p->kcountsize + p->fromssize + p->tossize));
- if (cp == (char *)-1) {
+ cp = sbrk((intptr_t)0);
+
+#define GMON_ALLOC(buf, ptr, size) \
+ do { \
+ (buf) = (void *)roundup((uintptr_t)(buf), __alignof(*(ptr))); \
+ (ptr) = (void *)(buf); \
+ (buf) += (size); \
+ } while (0)
+
+ GMON_ALLOC(cp, p->kcount, p->kcountsize);
+ GMON_ALLOC(cp, p->froms, p->fromssize);
+ GMON_ALLOC(cp, p->tos, p->tossize);
+
+ if (brk(cp)) {
warnx("%s: out of memory", __func__);
return;
}
-#ifdef notdef
- (void)memset(cp, 0, p->kcountsize + p->fromssize + p->tossize);
-#endif
- p->tos = (struct tostruct *)(void *)cp;
- cp += (size_t)p->tossize;
- p->kcount = (u_short *)(void *)cp;
- cp += (size_t)p->kcountsize;
- p->froms = (u_short *)(void *)cp;
+ __minbrk = cp;
- __minbrk = sbrk((intptr_t)0);
p->tos[0].link = 0;
o = p->highpc - p->lowpc;
@@ -226,17 +230,22 @@ _m_gmon_alloc(void)
} else {
mutex_unlock(&_gmonlock);
cp = mmap(NULL,
- (size_t)(sizeof (struct gmonparam) +
- _gmonparam.fromssize + _gmonparam.tossize),
+ (size_t)(__alignof(*p) + sizeof(*p) +
+ __alignof(*_gmonparam.froms) + _gmonparam.fromssize +
+ __alignof(*_gmonparam.tos) + _gmonparam.tossize),
PROT_READ|PROT_WRITE, MAP_ANON|MAP_PRIVATE, -1, (off_t)0);
- p = (void *)cp;
+
+ GMON_ALLOC(cp, p, sizeof(*p));
*p = _gmonparam;
p->state = GMON_PROF_ON;
p->kcount = NULL;
- cp += sizeof (struct gmonparam);
- memset(cp, 0, (size_t)(p->fromssize + p->tossize));
- p->froms = (u_short *)(void *)cp;
- p->tos = (struct tostruct *)(void *)(cp + p->fromssize);
+
+ GMON_ALLOC(cp, p->froms, p->fromssize);
+ memset(p->froms, 0, p->fromssize);
+
+ GMON_ALLOC(cp, p->tos, p->tossize);
+ memset(p->tos, 0, p->tossize);
+
mutex_lock(&_gmonlock);
p->kcount = (u_short *)(void *)_gmoninuse;
_gmoninuse = p;
