tlibthread: use mmap to allocate OpenBSD stacks - plan9port - [fork] Plan 9 from user space
(HTM) git clone git://src.adamsgaard.dk/plan9port
(DIR) Log
(DIR) Files
(DIR) Refs
(DIR) README
(DIR) LICENSE
---
(DIR) commit 8c573cab6819c69142389d36b978b3c683771afe
(DIR) parent 4ae529dbfe8573ae105d0d66f7f453c4f850fa1f
(HTM) Author: Russ Cox <rsc@swtch.com>
Date: Tue, 14 Jan 2020 12:40:09 -0500
libthread: use mmap to allocate OpenBSD stacks
Should fix faults on OpenBSD.
Fixes #218.
Fixes #226.
Diffstat:
M src/libthread/Darwin-x86_64-swapco… | 8 ++++++++
A src/libthread/stkmalloc.c | 13 +++++++++++++
A src/libthread/stkmmap.c | 25 +++++++++++++++++++++++++
M src/libthread/sysofiles.sh | 12 ++++++------
M src/libthread/thread.c | 9 +++++++--
M src/libthread/threadimpl.h | 2 ++
6 files changed, 61 insertions(+), 8 deletions(-)
---
(DIR) diff --git a/src/libthread/Darwin-x86_64-swapcontext.c b/src/libthread/Darwin-x86_64-swapcontext.c
t@@ -16,6 +16,14 @@ makecontext(ucontext_t *uc, void (*fn)(void), int argc, ...)
va_end(arg);
sp = (uintptr*)((char*)uc->uc_stack.ss_sp+uc->uc_stack.ss_size);
+ /*
+ * Stack pointer at call instruction (before return address
+ * gets pushed) must be 16-byte aligned.
+ */
+ if((uintptr)sp%4)
+ abort();
+ while((uintptr)sp%16 != 0)
+ sp--;
*--sp = 0; // fn's return address
*--sp = (uintptr)fn; // return address of setcontext
uc->mc.sp = (uintptr)sp;
(DIR) diff --git a/src/libthread/stkmalloc.c b/src/libthread/stkmalloc.c
t@@ -0,0 +1,13 @@
+#include "threadimpl.h"
+
+void*
+_threadstkalloc(int n)
+{
+ return malloc(n);
+}
+
+void
+_threadstkfree(void *v, int n)
+{
+ free(v);
+}
(DIR) diff --git a/src/libthread/stkmmap.c b/src/libthread/stkmmap.c
t@@ -0,0 +1,25 @@
+#include <u.h>
+#include <sys/mman.h>
+#include "threadimpl.h"
+
+#ifndef MAP_STACK
+#define MAP_STACK 0
+#endif
+
+void*
+_threadstkalloc(int n)
+{
+ void *p;
+
+ p = mmap(nil, n, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANON|MAP_STACK, -1, 0);
+ if(p == (void*)-1)
+ return nil;
+ return p;
+}
+
+void
+_threadstkfree(void *v, int n)
+{
+ if(n > 0)
+ munmap(v, n);
+}
(DIR) diff --git a/src/libthread/sysofiles.sh b/src/libthread/sysofiles.sh
t@@ -6,22 +6,22 @@ tag="$OBJTYPE-$SYSNAME-${SYSVERSION:-`uname -r`}-${CC9:-cc}"
case "$tag" in
*-Linux-2.[0-5]*)
# will have to fix this for linux power pc
- echo ${SYSNAME}-${OBJTYPE}-asm.o $SYSNAME.o
+ echo ${SYSNAME}-${OBJTYPE}-asm.o $SYSNAME.o stkmalloc.o
;;
*-FreeBSD-[0-4].*)
- echo ${SYSNAME}-${OBJTYPE}-asm.o $SYSNAME.o
+ echo ${SYSNAME}-${OBJTYPE}-asm.o $SYSNAME.o stkmalloc.o
;;
*-NetBSD-*)
- echo ${SYSNAME}-${OBJTYPE}-asm.o $SYSNAME.o
+ echo ${SYSNAME}-${OBJTYPE}-asm.o $SYSNAME.o stkmalloc.o
;;
*-Darwin-10.[5-6].* | *-Darwin-[89].*)
- echo ${SYSNAME}-${OBJTYPE}-asm.o $SYSNAME-${OBJTYPE}.o pthread.o
+ echo ${SYSNAME}-${OBJTYPE}-asm.o $SYSNAME-${OBJTYPE}.o pthread.o stkmalloc.o
;;
*-OpenBSD-*)
- echo ${SYSNAME}-${OBJTYPE}-asm.o ${SYSNAME}-${OBJTYPE}.o pthread.o
+ echo ${SYSNAME}-${OBJTYPE}-asm.o ${SYSNAME}-${OBJTYPE}.o pthread.o stkmmap.o
;;
*)
- echo pthread.o
+ echo pthread.o stkmalloc.o
esac
case "$OBJTYPE-$SYSNAME" in
(DIR) diff --git a/src/libthread/thread.c b/src/libthread/thread.c
t@@ -109,7 +109,7 @@ threadalloc(void (*fn)(void*), void *arg, uint stack)
ulong z;
/* allocate the task and stack together */
- t = malloc(sizeof *t+stack);
+ t = malloc(sizeof *t);
if(t == nil)
sysfatal("threadalloc malloc: %r");
memset(t, 0, sizeof *t);
t@@ -122,7 +122,9 @@ threadalloc(void (*fn)(void*), void *arg, uint stack)
/* do a reasonable initialization */
if(stack == 0)
return t;
- t->stk = (uchar*)(t+1);
+ t->stk = _threadstkalloc(stack);
+ if(t->stk == nil)
+ sysfatal("threadalloc malloc stack: %r");
t->stksize = stack;
memset(&t->context.uc, 0, sizeof t->context.uc);
sigemptyset(&zero);
t@@ -353,6 +355,7 @@ Top:
delthreadinproc(p, t);
p->nthread--;
/*print("nthread %d\n", p->nthread); */
+ _threadstkfree(t->stk, t->stksize);
free(t);
}
t@@ -509,6 +512,8 @@ needstack(int n)
_Thread *t;
t = proc()->thread;
+ if(t->stk == nil)
+ return;
if((char*)&t <= (char*)t->stk
|| (char*)&t - (char*)t->stk < 256+n){
(DIR) diff --git a/src/libthread/threadimpl.h b/src/libthread/threadimpl.h
t@@ -209,3 +209,5 @@ extern void _threadsetupdaemonize(void);
extern void _threaddodaemonize(char*);
extern void _threadpexit(void);
extern void _threaddaemonize(void);
+extern void *_threadstkalloc(int);
+extern void _threadstkfree(void*, int);