From: Serge E. Hallyn <serue@xxxxxxxxxx>
Signed-off-by: Serge E. Hallyn <serue@xxxxxxxxxx>
---
clone_s390x.c | 100 ++++++++++++++++++++++++++++++++++++++------------------
1 files changed, 68 insertions(+), 32 deletions(-)
diff --git a/clone_s390x.c b/clone_s390x.c
index dada822..945a98d 100644
--- a/clone_s390x.c
+++ b/clone_s390x.c
@@ -13,17 +13,20 @@
#define _GNU_SOURCE
#include <unistd.h>
+#include <string.h>
+#include <malloc.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/syscall.h>
#include <asm/unistd.h>
+#define __NR_eclone 332
/*
- * libc doesn't support clone_with_pid() yet...
+ * libc doesn't support eclone() yet...
* below is arch-dependent code to use the syscall
*/
#include <linux/checkpoint.h>
-#if defined(__NR_clone_with_pids)
+#if defined(__NR_eclone)
/* this really belongs to some kernel header ! */
struct pid_set {
@@ -31,42 +34,75 @@ struct pid_set {
pid_t *pids;
};
-/* (see: http://lkml.indiana.edu/hypermail/linux/kernel/9604.3/0204.html) */
+typedef unsigned long long u64;
+typedef unsigned int u32;
+typedef int pid_t;
+struct clone_args {
+ u64 clone_flags_high;
+ u64 child_stack;
+ u64 child_stack_size;
+ u64 parent_tid_ptr;
+ u64 child_tid_ptr;
-#define do_clone_with_pids(stack, flags, ptid, ctid, setp) ({ \
- register unsigned long int __r2 asm ("2") = (unsigned long int)(stack);\
- register unsigned long int __r3 asm ("3") = (unsigned long int)(flags);\
- register unsigned long int __r4 asm ("4") = (unsigned long int)(ptid); \
- register unsigned long int __r5 asm ("5") = (unsigned long int)(ctid); \
- register unsigned long int __r6 asm ("6") = (unsigned long int)(NULL); \
- register unsigned long int __r7 asm ("7") = (unsigned long int)(setp); \
- register unsigned long int __result asm ("2"); \
- __asm__ __volatile__( \
- " lghi %%r1,%7\n" \
- " svc 0\n" \
- : "=d" (__result) \
- : "0" (__r2), "d" (__r3), \
- "d" (__r4), "d" (__r5), "d" (__r6), "d" (__r7), \
- "i" (__NR_clone_with_pids) \
- : "1", "cc", "memory" \
- ); \
- __result; \
- })
+ u32 nr_pids;
+
+ u32 reserved0;
+ u64 reserved1;
+};
+
+#define do_eclone(flags, pids, args, sz) \
+( { \
+ register unsigned long int __r1 asm ("1") = (unsigned long int)(__NR_eclone); \
+ register unsigned long int __r2 asm ("2") = (unsigned long int)(flags); \
+ register unsigned long int __r3 asm ("3") = (unsigned long int)(args); \
+ register unsigned long int __r4 asm ("4") = (unsigned long int)(sz); \
+ register unsigned long int __r5 asm ("5") = (unsigned long int)(pids); \
+ register long int __result asm ("2"); \
+ __asm__ __volatile__( \
+ " svc 0\n" /* do __NR_eclone syscall */ \
+ " ltgr %%r2,%%r2\n" /* returned 0? */ \
+ " jnz 1f\n" /* if not goto label 1 */ \
+ " lg %%r3,0(%%r15)\n" /* get fnarg off stack into arg 1 */ \
+ " lg %%r2,8(%%r15)\n" /* get fn off stack int r3 basr*/ \
+ " lgr %%r1,%%r15\n" /* tmp store old stack pointer */ \
+ " aghi %%r15,-160\n" /* move the stack */ \
+ " stg %%r1,0(%%r15)\n" /* and save old stack pointer */ \
+ " basr %%r14,%%r3\n" /* call fn(arg) */ \
+ " svc 1\n" /* call exit */ \
+ " 1:\n" \
+ : "=d" (__result) \
+ : "d" (__r1), "0" (__r2), "d" (__r3), "d" (__r4), "d" (__r5) \
+ : "memory"); \
+ __result; \
+} )
+
int clone_with_pids(int (*fn)(void *), void *child_stack, int flags,
struct pid_set *target_pids, void *arg)
{
- long retval;
- retval = do_clone_with_pids(child_stack, flags, NULL, NULL,
- target_pids);
+ struct clone_args clone_args, *ca = &clone_args;
+ u64 *s;
+
+ memset(ca, 0, sizeof(struct clone_args));
+ ca->nr_pids = target_pids->num_pids;
+ if (!child_stack) {
+ /* we could pass in null and then in eclone not
+ * call exit if child_stack was null, but we'll
+ * just malloc here */
+ int sz = 4*getpagesize();
+ child_stack = malloc(sz);
+ if (!child_stack)
+ return -ENOMEM;
+ child_stack += sz; /* we'll decrement before assigning */
+ }
+ ca->child_stack = (u64) child_stack;
+ s = (u64 *) ca->child_stack;
+ *--s = (u64) arg;
+ *--s = (u64) fn;
+ ca->child_stack -= 16;
- if (retval < 0) {
- errno = -retval;
- return -1;
- } else if (retval == 0) {
- return fn(arg);
- } else
- return retval;
+ return do_eclone(flags, target_pids->pids, ca,
+ sizeof(struct clone_args));
}
#endif /* !defined(__NR_clone_with_pids) */
--
1.6.1.1
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