# HG changeset patch
# User yamahata@xxxxxxxxxxxxx
# Date 1164116163 -32400
# Node ID d4f466290efa229fd6dcb2be8439b0f8c113a231
# Parent  7f8a27d2f0eda3c96cf3c3ae9d1cac91dad30065
fix paravirtualization of clone2() system call.
If audit is enabled or the child process is ptraced,
non-paravirtualized code path is executed.
Thus paravirtualized ifs is left unmodifed so that the child process
crashes after clone2().
paravirtualize ia64_ret_from_clone() to fix it.
PATCHNAME: paravirtualize_ia64_ret_from_clone2

Signed-off-by: Isaku Yamahata <yamahata@xxxxxxxxxxxxx>

diff -r 7f8a27d2f0ed -r d4f466290efa linux-2.6-xen-sparse/arch/ia64/kernel/entry.S
--- a/linux-2.6-xen-sparse/arch/ia64/kernel/entry.S	Tue Nov 21 21:54:39 2006 +0900
+++ b/linux-2.6-xen-sparse/arch/ia64/kernel/entry.S	Tue Nov 21 22:36:03 2006 +0900
@@ -602,7 +602,7 @@ GLOBAL_ENTRY(ia64_strace_leave_kernel)
 .ret4:	br.cond.sptk ia64_leave_kernel
 END(ia64_strace_leave_kernel)
 
-GLOBAL_ENTRY(ia64_ret_from_clone)
+GLOBAL_ENTRY(__ia64_ret_from_clone)
 	PT_REGS_UNWIND_INFO(0)
 {	/*
 	 * Some versions of gas generate bad unwind info if the first instruction of a
@@ -628,7 +628,7 @@ GLOBAL_ENTRY(ia64_ret_from_clone)
 	cmp.ne p6,p0=r2,r0
 (p6)	br.cond.spnt .strace_check_retval
 	;;					// added stop bits to prevent r8 dependency
-END(ia64_ret_from_clone)
+END(__ia64_ret_from_clone)
 	// fall through
 GLOBAL_ENTRY(ia64_ret_from_syscall)
 	PT_REGS_UNWIND_INFO(0)
diff -r 7f8a27d2f0ed -r d4f466290efa linux-2.6-xen-sparse/arch/ia64/xen/xenentry.S
--- a/linux-2.6-xen-sparse/arch/ia64/xen/xenentry.S	Tue Nov 21 21:54:39 2006 +0900
+++ b/linux-2.6-xen-sparse/arch/ia64/xen/xenentry.S	Tue Nov 21 22:36:03 2006 +0900
@@ -237,6 +237,47 @@ END(ia64_trace_syscall)
 END(ia64_trace_syscall)
 #endif
 
+#ifdef CONFIG_XEN
+GLOBAL_ENTRY(xen_ret_from_clone)
+	PT_REGS_UNWIND_INFO(0)
+	movl r16=running_on_xen;;
+	ld4 r16=[r16];;
+	cmp.eq p7,p0=r16,r0
+(p7)	br.cond.sptk.many __ia64_ret_from_clone;;
+#else	
+GLOBAL_ENTRY(ia64_ret_from_clone)
+	PT_REGS_UNWIND_INFO(0)
+#endif	
+{	/*
+	 * Some versions of gas generate bad unwind info if the first instruction of a
+	 * procedure doesn't go into the first slot of a bundle.  This is a workaround.
+	 */
+	nop.m 0
+	nop.i 0
+	/*
+	 * We need to call schedule_tail() to complete the scheduling process.
+	 * Called by ia64_switch_to() after do_fork()->copy_thread().  r8 contains the
+	 * address of the previously executing task.
+	 */
+	br.call.sptk.many rp=ia64_invoke_schedule_tail
+}
+.ret8:
+	adds r2=TI_FLAGS+IA64_TASK_SIZE,r13
+	;;
+	ld4 r2=[r2]
+	;;
+	mov r8=0
+	and r2=_TIF_SYSCALL_TRACEAUDIT,r2
+	;;
+	cmp.ne p6,p0=r2,r0
+(p6)	br.cond.spnt .strace_check_retval
+	;;					// added stop bits to prevent r8 dependency
+#ifdef CONFIG_XEN
+	br.cond.sptk ia64_ret_from_syscall
+END(xen_ret_from_clone)
+#else
+END(ia64_ret_from_clone)
+#endif		
 /*
  * ia64_leave_syscall(): Same as ia64_leave_kernel, except that it doesn't
  *	need to switch to bank 0 and doesn't restore the scratch registers.
diff -r 7f8a27d2f0ed -r d4f466290efa linux-2.6-xen-sparse/include/asm-ia64/privop.h
--- a/linux-2.6-xen-sparse/include/asm-ia64/privop.h	Tue Nov 21 21:54:39 2006 +0900
+++ b/linux-2.6-xen-sparse/include/asm-ia64/privop.h	Tue Nov 21 22:36:03 2006 +0900
@@ -49,6 +49,7 @@
 #define ia64_leave_kernel		__ia64_leave_kernel
 #define ia64_leave_syscall		__ia64_leave_syscall
 #define ia64_trace_syscall		__ia64_trace_syscall
+#define ia64_ret_from_clone		__ia64_ret_from_clone
 #define ia64_switch_to			__ia64_switch_to
 #define ia64_pal_call_static		__ia64_pal_call_static
 
diff -r 7f8a27d2f0ed -r d4f466290efa linux-2.6-xen-sparse/include/asm-ia64/xen/privop.h
--- a/linux-2.6-xen-sparse/include/asm-ia64/xen/privop.h	Tue Nov 21 21:54:39 2006 +0900
+++ b/linux-2.6-xen-sparse/include/asm-ia64/xen/privop.h	Tue Nov 21 22:36:03 2006 +0900
@@ -295,6 +295,7 @@ extern void xen_ptcga(unsigned long addr
 #define	ia64_leave_kernel		xen_leave_kernel
 #define	ia64_leave_syscall		xen_leave_syscall
 #define	ia64_trace_syscall		xen_trace_syscall
+#define	ia64_ret_from_clone		xen_ret_from_clone
 #define	ia64_switch_to			xen_switch_to
 #define	ia64_pal_call_static		xen_pal_call_static