ia64: switch to generic kernel_thread()/kernel_execve()

Acked-by: Tony Luck <tony.luck@intel.com>
Tested-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 22 insertions, 7 deletions

diff --git a/arch/ia64/kernel/entry.S b/arch/ia64/kernel/entry.S
index 6b0648d97b4c..0dea684e1905 100644
--- a/arch/ia64/kernel/entry.S
+++ b/arch/ia64/kernel/entry.S
@@ -484,13 +484,6 @@ GLOBAL_ENTRY(prefetch_stack)
         br.ret.sptk.many rp
 END(prefetch_stack)
 
-GLOBAL_ENTRY(kernel_execve)
-        rum psr.ac
-        mov r15=__NR_execve                     // put syscall number in place
-        break __BREAK_SYSCALL
-        br.ret.sptk.many rp
-END(kernel_execve)
-
         /*
          * Invoke a system call, but do some tracing before and after the call.
          * We MUST preserve the current register frame throughout this routine
@@ -594,6 +587,27 @@ GLOBAL_ENTRY(ia64_strace_leave_kernel)
 .ret4:  br.cond.sptk ia64_leave_kernel
 END(ia64_strace_leave_kernel)
 
+ENTRY(call_payload)
+        .prologue ASM_UNW_PRLG_RP|ASM_UNW_PRLG_PFS, ASM_UNW_PRLG_GRSAVE(0)
+        /* call the kernel_thread payload; fn is in r4, arg - in r5 */
+        alloc loc1=ar.pfs,0,3,1,0
+        mov loc0=rp
+        mov loc2=gp
+        mov out0=r5             // arg
+        ld8 r14 = [r4], 8       // fn.address
+        ;;
+        mov b6 = r14
+        ld8 gp = [r4]           // fn.gp
+        ;;
+        br.call.sptk.many rp=b6 // fn(arg)
+.ret12: mov gp=loc2
+        mov rp=loc0
+        mov ar.pfs=loc1
+        /* ... and if it has returned, we are going to userland */
+        cmp.ne pKStk,pUStk=r0,r0
+        br.ret.sptk.many rp
+END(call_payload)
+
 GLOBAL_ENTRY(ia64_ret_from_clone)
         PT_REGS_UNWIND_INFO(0)
 {       /*
@@ -610,6 +624,7 @@ GLOBAL_ENTRY(ia64_ret_from_clone)
         br.call.sptk.many rp=ia64_invoke_schedule_tail
 }
 .ret8:
+(pKStk) br.call.sptk.many rp=call_payload
         adds r2=TI_FLAGS+IA64_TASK_SIZE,r13
         ;;
         ld4 r2=[r2]