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Subject[PATCH v18 58/80] c/r: clone_with_pids: define the s390 syscall
Date
From: Serge E. Hallyn <serue@us.ibm.com>

Hook up the clone_with_pids system call for s390x. clone_with_pids()
takes an additional argument over clone(), which we pass in through
register 7. Stub code for using the syscall looks like:

struct target_pid_set {
int num_pids;
pid_t *target_pids;
unsigned long flags;
};

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)(NULL);
register unsigned long int __r5 asm ("5") = (unsigned long int)(NULL);
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 %%r1,332\n"
" svc 0\n"
: "=d" (__result)
: "0" (__r2), "d" (__r3),
"d" (__r4), "d" (__r5), "d" (__r6), "d" (__r7)
: "1", "cc", "memory"
);
__result;
})

struct target_pid_set pid_set;
int pids[1] = { 19799 };
pid_set.num_pids = 1;
pid_set.target_pids = &pids[0];
pid_set.flags = 0;

rc = do_clone_with_pids(topstack, clone_flags, setp);
if (rc == 0)
printf("Child\n");
else if (rc > 0)
printf("Parent: child pid %d\n", rc);
else
printf("Error %d\n", rc);

Changelog[v18]:
- Set return value for self-checkpoint

Signed-off-by: Serge E. Hallyn <serue@us.ibm.com>
---
arch/s390/include/asm/unistd.h | 3 ++-
arch/s390/kernel/compat_linux.c | 19 +++++++++++++++++++
arch/s390/kernel/process.c | 19 +++++++++++++++++++
arch/s390/kernel/syscalls.S | 1 +
4 files changed, 41 insertions(+), 1 deletions(-)

diff --git a/arch/s390/include/asm/unistd.h b/arch/s390/include/asm/unistd.h
index 5d1678a..2a84f9c 100644
--- a/arch/s390/include/asm/unistd.h
+++ b/arch/s390/include/asm/unistd.h
@@ -271,7 +271,8 @@
#define __NR_perf_counter_open 331
#define __NR_checkpoint 332
#define __NR_restart 333
-#define NR_syscalls 334
+#define __NR_clone_with_pids 334
+#define NR_syscalls 335

/*
* There are some system calls that are not present on 64 bit, some
diff --git a/arch/s390/kernel/compat_linux.c b/arch/s390/kernel/compat_linux.c
index 9ab188d..c6dc681 100644
--- a/arch/s390/kernel/compat_linux.c
+++ b/arch/s390/kernel/compat_linux.c
@@ -818,6 +818,25 @@ asmlinkage long sys32_clone(void)
parent_tidptr, child_tidptr);
}

+asmlinkage long sys32_clone_with_pids(void)
+{
+ struct pt_regs *regs = task_pt_regs(current);
+ unsigned long clone_flags;
+ unsigned long newsp;
+ int __user *parent_tidptr, *child_tidptr;
+ void __user *upid_setp;
+
+ clone_flags = regs->gprs[3] & 0xffffffffUL;
+ newsp = regs->orig_gpr2 & 0x7fffffffUL;
+ parent_tidptr = compat_ptr(regs->gprs[4]);
+ child_tidptr = compat_ptr(regs->gprs[5]);
+ upid_setp = compat_ptr(regs->gprs[7]);
+ if (!newsp)
+ newsp = regs->gprs[15];
+ return do_fork_with_pids(clone_flags, newsp, regs, 0,
+ parent_tidptr, child_tidptr, upid_setp);
+}
+
/*
* 31 bit emulation wrapper functions for sys_fadvise64/fadvise64_64.
* These need to rewrite the advise values for POSIX_FADV_{DONTNEED,NOREUSE}
diff --git a/arch/s390/kernel/process.c b/arch/s390/kernel/process.c
index 5a43f27..263d3ab 100644
--- a/arch/s390/kernel/process.c
+++ b/arch/s390/kernel/process.c
@@ -247,6 +247,25 @@ SYSCALL_DEFINE0(clone)
parent_tidptr, child_tidptr);
}

+SYSCALL_DEFINE0(clone_with_pids)
+{
+ struct pt_regs *regs = task_pt_regs(current);
+ unsigned long clone_flags;
+ unsigned long newsp;
+ int __user *parent_tidptr, *child_tidptr;
+ void __user *upid_setp;
+
+ clone_flags = regs->gprs[3];
+ newsp = regs->orig_gpr2;
+ parent_tidptr = (int __user *) regs->gprs[4];
+ child_tidptr = (int __user *) regs->gprs[5];
+ upid_setp = (void __user *) regs->gprs[7];
+ if (!newsp)
+ newsp = regs->gprs[15];
+ return do_fork_with_pids(clone_flags, newsp, regs, 0, parent_tidptr,
+ child_tidptr, upid_setp);
+}
+
/*
* This is trivial, and on the face of it looks like it
* could equally well be done in user mode.
diff --git a/arch/s390/kernel/syscalls.S b/arch/s390/kernel/syscalls.S
index 67518e2..db850e7 100644
--- a/arch/s390/kernel/syscalls.S
+++ b/arch/s390/kernel/syscalls.S
@@ -342,3 +342,4 @@ SYSCALL(sys_rt_tgsigqueueinfo,sys_rt_tgsigqueueinfo,compat_sys_rt_tgsigqueueinfo
SYSCALL(sys_perf_counter_open,sys_perf_counter_open,sys_perf_counter_open_wrapper)
SYSCALL(sys_checkpoint,sys_checkpoint,sys_checkpoint_wrapper)
SYSCALL(sys_restart,sys_restart,sys_restore_wrapper)
+SYSCALL(sys_clone_with_pids,sys_clone_with_pids,sys_clone_with_pids_wrapper)
--
1.6.0.4


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