[PATCH] powerpc: Wire up clone3 syscall

[Michael Ellerman]

Wire up the new clone3 syscall added in commit 7f192e3cd316 ("fork:
add clone3").

This requires a ppc_clone3 wrapper, in order to save the non-volatile
GPRs before calling into the generic syscall code. Otherwise we hit
the BUG_ON in CHECK_FULL_REGS in copy_thread().

Lightly tested using Christian's test code on a Power8 LE VM.

Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Acked-by: Christian Brauner <christian@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20190722132231.10169-1-mpe@xxxxxxxxxxxxxx
---
 arch/powerpc/include/asm/unistd.h        | 1 +
 arch/powerpc/kernel/entry_64.S           | 5 +++++
 arch/powerpc/kernel/syscalls/syscall.tbl | 2 +-
 3 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/include/asm/unistd.h b/arch/powerpc/include/asm/unistd.h
index 68473c3c471c..b0720c7c3fcf 100644
--- a/arch/powerpc/include/asm/unistd.h
+++ b/arch/powerpc/include/asm/unistd.h
@@ -49,6 +49,7 @@
 #define __ARCH_WANT_SYS_FORK
 #define __ARCH_WANT_SYS_VFORK
 #define __ARCH_WANT_SYS_CLONE
+#define __ARCH_WANT_SYS_CLONE3
 
 #endif		/* __ASSEMBLY__ */
 #endif /* _ASM_POWERPC_UNISTD_H_ */
diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S
index d9105fcf4021..0a0b5310f54a 100644
--- a/arch/powerpc/kernel/entry_64.S
+++ b/arch/powerpc/kernel/entry_64.S
@@ -487,6 +487,11 @@ _GLOBAL(ppc_clone)
 	bl	sys_clone
 	b	.Lsyscall_exit
 
+_GLOBAL(ppc_clone3)
+       bl      save_nvgprs
+       bl      sys_clone3
+       b       .Lsyscall_exit
+
 _GLOBAL(ppc32_swapcontext)
 	bl	save_nvgprs
 	bl	compat_sys_swapcontext
diff --git a/arch/powerpc/kernel/syscalls/syscall.tbl b/arch/powerpc/kernel/syscalls/syscall.tbl
index 3331749aab20..6886ecb590d5 100644
--- a/arch/powerpc/kernel/syscalls/syscall.tbl
+++ b/arch/powerpc/kernel/syscalls/syscall.tbl
@@ -516,4 +516,4 @@
 432	common	fsmount				sys_fsmount
 433	common	fspick				sys_fspick
 434	common	pidfd_open			sys_pidfd_open
-# 435 reserved for clone3
+435	common	clone3				ppc_clone3
-- 
2.22.0