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authorRuss Cox <rsc@swtch.com>2020-01-14 12:40:09 -0500
committerRuss Cox <rsc@swtch.com>2020-01-14 13:58:47 -0500
commit8c573cab6819c69142389d36b978b3c683771afe (patch)
tree8c97a0523b4b9dbddc2ad5afc49e89d9815ecbda /src
parent4ae529dbfe8573ae105d0d66f7f453c4f850fa1f (diff)
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libthread: use mmap to allocate OpenBSD stacks
Should fix faults on OpenBSD. Fixes #218. Fixes #226.
Diffstat (limited to 'src')
-rw-r--r--src/libthread/Darwin-x86_64-swapcontext.c8
-rw-r--r--src/libthread/stkmalloc.c13
-rw-r--r--src/libthread/stkmmap.c25
-rw-r--r--src/libthread/sysofiles.sh12
-rw-r--r--src/libthread/thread.c9
-rw-r--r--src/libthread/threadimpl.h2
6 files changed, 61 insertions, 8 deletions
diff --git a/src/libthread/Darwin-x86_64-swapcontext.c b/src/libthread/Darwin-x86_64-swapcontext.c
index 27931456..c29ddb5e 100644
--- a/src/libthread/Darwin-x86_64-swapcontext.c
+++ b/src/libthread/Darwin-x86_64-swapcontext.c
@@ -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;
diff --git a/src/libthread/stkmalloc.c b/src/libthread/stkmalloc.c
new file mode 100644
index 00000000..083aea1b
--- /dev/null
+++ b/src/libthread/stkmalloc.c
@@ -0,0 +1,13 @@
+#include "threadimpl.h"
+
+void*
+_threadstkalloc(int n)
+{
+ return malloc(n);
+}
+
+void
+_threadstkfree(void *v, int n)
+{
+ free(v);
+}
diff --git a/src/libthread/stkmmap.c b/src/libthread/stkmmap.c
new file mode 100644
index 00000000..f4a24630
--- /dev/null
+++ b/src/libthread/stkmmap.c
@@ -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);
+}
diff --git a/src/libthread/sysofiles.sh b/src/libthread/sysofiles.sh
index 9eeea606..f76b975a 100644
--- a/src/libthread/sysofiles.sh
+++ b/src/libthread/sysofiles.sh
@@ -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
diff --git a/src/libthread/thread.c b/src/libthread/thread.c
index d041efcc..2e654863 100644
--- a/src/libthread/thread.c
+++ b/src/libthread/thread.c
@@ -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);
@@ -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);
@@ -353,6 +355,7 @@ Top:
delthreadinproc(p, t);
p->nthread--;
/*print("nthread %d\n", p->nthread); */
+ _threadstkfree(t->stk, t->stksize);
free(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){
diff --git a/src/libthread/threadimpl.h b/src/libthread/threadimpl.h
index 76ca57e5..6671f23c 100644
--- a/src/libthread/threadimpl.h
+++ b/src/libthread/threadimpl.h
@@ -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);