Re: [PATCH] make checkpoint a ptregs syscall as well

[Oren Laadan <orenl-eQaUEPhvms7ENvBUuze7eA@public.gmane.org>]

... silly me -- I should have seen that when I fixed it for restart !
Added, thanks.

Oren.

Serge E. Hallyn wrote:
> This is on top of the 64-bit patches which Oren posted on Dec 6, so
> it does not work with my cr-next branch or Oren's ckpt-v19-rc2, and
> s390 and powerpc will need corresponding patches.
> 
> Without this, restart of self-checkpoint fails (understandably) on the
> amd64 test system I'm borrowing.
> 
> I have not yet tested restart of checkpointed 32-bit program on 64-bit
> machine.  Or for that matter a 32bit kernel.
> 
> Thanks, Nathan, for finding the problem!  I should have guessed, based
> on my symptoms.
> 
> Signed-off-by: Serge Hallyn <serue-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org>
> ---
>  arch/x86/include/asm/syscalls.h    |    3 +++
>  arch/x86/include/asm/unistd_64.h   |    2 +-
>  arch/x86/kernel/checkpoint_64.c    |   10 ++++++++++
>  arch/x86/kernel/entry_32.S         |    1 +
>  arch/x86/kernel/entry_64.S         |    2 ++
>  arch/x86/kernel/syscall_table_32.S |    2 +-
>  checkpoint/sys.c                   |    5 ++---
>  include/linux/checkpoint.h         |    2 ++
>  include/linux/syscalls.h           |    2 --
>  9 files changed, 22 insertions(+), 7 deletions(-)
> 
> diff --git a/arch/x86/include/asm/syscalls.h b/arch/x86/include/asm/syscalls.h
> index 063cdd0..35b2060 100644
> --- a/arch/x86/include/asm/syscalls.h
> +++ b/arch/x86/include/asm/syscalls.h
> @@ -45,6 +45,7 @@ int sys_execve(struct pt_regs *);
>  
>  /* kernel/checkpoint_32.c */
>  #ifdef CONFIG_CHECKPOINT
> +long sys_checkpoint(struct pt_regs *);
>  long sys_restart(struct pt_regs *);
>  #endif
>  
> @@ -90,6 +91,8 @@ long sys_arch_prctl(int, unsigned long);
>  
>  /* kernel/checkpoint_64.c */
>  #ifdef CONFIG_CHECKPOINT
> +asmlinkage long sys_checkpoint(pid_t pid, int fd, unsigned long flags,
> +				int logfd, struct pt_regs *regs);
>  asmlinkage long sys_restart(pid_t pid, int fd, unsigned long flags, int logfd,
>  			    struct pt_regs *regs);
>  #endif
> diff --git a/arch/x86/include/asm/unistd_64.h b/arch/x86/include/asm/unistd_64.h
> index c360707..e443304 100644
> --- a/arch/x86/include/asm/unistd_64.h
> +++ b/arch/x86/include/asm/unistd_64.h
> @@ -664,7 +664,7 @@ __SYSCALL(__NR_perf_event_open, sys_perf_event_open)
>  #define __NR_eclone                   		299
>  __SYSCALL(__NR_eclone, stub_eclone)
>  #define __NR_checkpoint                   	300
> -__SYSCALL(__NR_checkpoint, sys_checkpoint)
> +__SYSCALL(__NR_checkpoint, stub_checkpoint)
>  #define __NR_restart                   		301
>  __SYSCALL(__NR_restart, stub_restart)
>  
> diff --git a/arch/x86/kernel/checkpoint_64.c b/arch/x86/kernel/checkpoint_64.c
> index 87c1606..a63e88d 100644
> --- a/arch/x86/kernel/checkpoint_64.c
> +++ b/arch/x86/kernel/checkpoint_64.c
> @@ -22,6 +22,16 @@
>   * sys_restart needs to access and modify the pt_regs structure to
>   * restore the original state from the time of the checkpoint.
>   */
> +asmlinkage long sys_checkpoint(pid_t pid, int fd, unsigned long flags, int logfd,
> +			    struct pt_regs *regs)
> +{
> +	return do_sys_checkpoint(pid, fd, flags, logfd);
> +}
> +
> +/*
> + * sys_restart needs to access and modify the pt_regs structure to
> + * restore the original state from the time of the checkpoint.
> + */
>  asmlinkage long sys_restart(pid_t pid, int fd, unsigned long flags, int logfd,
>  			    struct pt_regs *regs)
>  {
> diff --git a/arch/x86/kernel/entry_32.S b/arch/x86/kernel/entry_32.S
> index ecefd09..76ec9c4 100644
> --- a/arch/x86/kernel/entry_32.S
> +++ b/arch/x86/kernel/entry_32.S
> @@ -727,6 +727,7 @@ PTREGSCALL(rt_sigreturn)
>  PTREGSCALL(vm86)
>  PTREGSCALL(vm86old)
>  #ifdef CONFIG_CHECKPOINT
> +PTREGSCALL(checkpoint)
>  PTREGSCALL(restart)
>  #endif
>  
> diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
> index e692193..ec6f43f 100644
> --- a/arch/x86/kernel/entry_64.S
> +++ b/arch/x86/kernel/entry_64.S
> @@ -700,8 +700,10 @@ END(\label)
>  	PTREGSCALL stub_iopl, sys_iopl, %rsi
>  	PTREGSCALL stub_eclone, sys_eclone, %r8
>  #ifdef CONFIG_CHECKPOINT
> +	PTREGSCALL stub_checkpoint, sys_checkpoint, %r8
>  	PTREGSCALL stub_restart, sys_restart, %r8
>  #else
> +	PTREGSCALL stub_checkpoint, sys_ni_syscall, %r8
>  	PTREGSCALL stub_restart, sys_ni_syscall, %r8
>  #endif
>  
> diff --git a/arch/x86/kernel/syscall_table_32.S b/arch/x86/kernel/syscall_table_32.S
> index 1ca053e..28fd000 100644
> --- a/arch/x86/kernel/syscall_table_32.S
> +++ b/arch/x86/kernel/syscall_table_32.S
> @@ -337,5 +337,5 @@ ENTRY(sys_call_table)
>  	.long sys_rt_tgsigqueueinfo	/* 335 */
>  	.long sys_perf_event_open
>  	.long ptregs_eclone
> -	.long sys_checkpoint
> +	.long ptregs_checkpoint
>  	.long ptregs_restart
> diff --git a/checkpoint/sys.c b/checkpoint/sys.c
> index 303e16f..c26682c 100644
> --- a/checkpoint/sys.c
> +++ b/checkpoint/sys.c
> @@ -605,7 +605,7 @@ int walk_task_subtree(struct task_struct *root,
>  /* checkpoint/restart syscalls */
>  
>  /**
> - * sys_checkpoint - checkpoint a container
> + * do_sys_checkpoint - checkpoint a container
>   * @pid: pid of the container init(1) process
>   * @fd: file to which dump the checkpoint image
>   * @flags: checkpoint operation flags
> @@ -614,8 +614,7 @@ int walk_task_subtree(struct task_struct *root,
>   * Returns positive identifier on success, 0 when returning from restart
>   * or negative value on error
>   */
> -SYSCALL_DEFINE4(checkpoint, pid_t, pid, int, fd,
> -		unsigned long, flags, int, logfd)
> +long do_sys_checkpoint(pid_t pid, int fd, unsigned long flags, int logfd)
>  {
>  	struct ckpt_ctx *ctx;
>  	long ret;
> diff --git a/include/linux/checkpoint.h b/include/linux/checkpoint.h
> index fb0f5e8..f569fb0 100644
> --- a/include/linux/checkpoint.h
> +++ b/include/linux/checkpoint.h
> @@ -60,6 +60,8 @@
>  #define CKPT_LSM_INFO_LEN 200
>  #define CKPT_LSM_STRING_MAX 1024
>  
> +extern long do_sys_checkpoint(pid_t pid, int fd, unsigned long flags,
> +				int logfd);
>  extern long do_sys_restart(pid_t pid, int fd, unsigned long flags, int logfd);
>  
>  extern int walk_task_subtree(struct task_struct *task,
> diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
> index 264a02e..a990ace 100644
> --- a/include/linux/syscalls.h
> +++ b/include/linux/syscalls.h
> @@ -872,8 +872,6 @@ asmlinkage long sys_pselect6(int, fd_set __user *, fd_set __user *,
>  asmlinkage long sys_ppoll(struct pollfd __user *, unsigned int,
>  			  struct timespec __user *, const sigset_t __user *,
>  			  size_t);
> -asmlinkage long sys_checkpoint(pid_t pid, int fd, unsigned long flags,
> -			       int logfd);
>  
>  int kernel_execve(const char *filename, char *const argv[], char *const envp[]);
>