On Thu, Jul 25, 2019 at 12:02:59AM +1000, Michael Ellerman wrote:
> 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 <m...@ellerman.id.au>
Acked-by: Christian Brauner <christ...@brauner.io>
> ---
> arch/powerpc/include/asm/unistd.h | 1 +
> arch/powerpc/kernel/entry_32.S | 8 ++++++++
> arch/powerpc/kernel/entry_64.S | 5 +++++
> arch/powerpc/kernel/syscalls/syscall.tbl | 1 +
> 4 files changed, 15 insertions(+)
>
> v2: Add the wrapper for 32-bit as well, don't allow SPU programs to call
> clone3 (switch ABI to nospu).
>
> v1: https://lore.kernel.org/r/20190722132231.10169-1-...@ellerman.id.au
>
> 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_32.S b/arch/powerpc/kernel/entry_32.S
> index 85fdb6d879f1..54fab22c9a43 100644
> --- a/arch/powerpc/kernel/entry_32.S
> +++ b/arch/powerpc/kernel/entry_32.S
> @@ -597,6 +597,14 @@ END_FTR_SECTION_IFSET(CPU_FTR_NEED_PAIRED_STWCX)
> stw r0,_TRAP(r1) /* register set saved */
> b sys_clone
>
> + .globl ppc_clone3
> +ppc_clone3:
> + SAVE_NVGPRS(r1)
> + lwz r0,_TRAP(r1)
> + rlwinm r0,r0,0,0,30 /* clear LSB to indicate full */
> + stw r0,_TRAP(r1) /* register set saved */
> + b sys_clone3
> +
> .globl ppc_swapcontext
> ppc_swapcontext:
> SAVE_NVGPRS(r1)
> 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 f2c3bda2d39f..43f736ed47f2 100644
> --- a/arch/powerpc/kernel/syscalls/syscall.tbl
> +++ b/arch/powerpc/kernel/syscalls/syscall.tbl
> @@ -516,3 +516,4 @@
> 432 common fsmount sys_fsmount
> 433 common fspick sys_fspick
> 434 common pidfd_open sys_pidfd_open
> +435 nospu clone3 ppc_clone3
> --
> 2.20.1
>
