To test this, you need to update the kernel headers for user-cr
$ scripts/extract_headers -s PATH_TO_CR_KERNEL
Oren.
Oren Laadan wrote:
> Signed-off-by: Oren Laadan <[email protected]>
> ---
> clone_x86_64.c | 88
> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> 1 files changed, 88 insertions(+), 0 deletions(-)
> create mode 100644 clone_x86_64.c
>
> diff --git a/clone_x86_64.c b/clone_x86_64.c
> new file mode 100644
> index 0000000..d6d7e6f
> --- /dev/null
> +++ b/clone_x86_64.c
> @@ -0,0 +1,88 @@
> +/*
> + * clone_x86_64.c: support for eclone() on x86_64
> + *
> + * Copyright (C) Oren Laadan <[email protected]>
> + * Copyright (C) Dave Hansen <[email protected]>
> + *
> + * This file is subject to the terms and conditions of the GNU General
> Public
> + * License. See the file COPYING in the main directory of the Linux
> + * distribution for more details.
> + */
> +
> +#define _GNU_SOURCE
> +
> +#include <unistd.h>
> +#include <errno.h>
> +#include <sys/types.h>
> +#include <sys/syscall.h>
> +#include <asm/unistd.h>
> +
> +/*
> + * libc doesn't support eclone() yet...
> + * below is arch-dependent code to use the syscall
> + */
> +#include <linux/checkpoint.h>
> +
> +#include "eclone.h"
> +
> +#ifndef __NR_eclone
> +#define __NR_eclone 299
> +#endif
> +
> +int eclone(int (*fn)(void *), void *fn_arg, int clone_flags_low,
> + struct clone_args *clone_args, pid_t *pids)
> +{
> + struct clone_args my_args;
> + long retval;
> + void **newstack;
> +
> + if (clone_args->child_stack) {
> + /*
> + * Set up the stack for child:
> + * - fn_arg will be the argument for the child function
> + * - the fn pointer will be loaded into ebx after the clone
> + */
> + newstack = (void **)(unsigned long)(clone_args->child_stack +
> + clone_args->child_stack_size);
> + *--newstack = fn_arg;
> + *--newstack = fn;
> + } else
> + newstack = (void **)0;
> +
> + my_args = *clone_args;
> + my_args.child_stack = (unsigned long)newstack;
> + my_args.child_stack_size = 0;
> +
> + __asm__ __volatile__(
> + "movq %6, %%r10\n\t" /* pids in r10*/
> + "syscall\n\t" /* Linux/x86_64 system call */
> + "testq %0,%0\n\t" /* check return value */
> + "jne 1f\n\t" /* jump if parent */
> + "popq %%rax\n\t" /* get subthread function */
> + "popq %%rdi\n\t" /* get the subthread function arg */
> + "call *%%rax\n\t" /* start subthread function */
> + "movq %2,%0\n\t"
> + "syscall\n" /* exit system call: exit subthread */
> + "1:\n\t"
> + :"=a" (retval)
> + :"0" (__NR_eclone), "i" (__NR_exit),
> + "D" (clone_flags_low), /* rdi */
> + "S" (&my_args), /* rsi */
> + "d" (sizeof(my_args)), /* rdx */
> + "m" (pids) /* gets moved to r10 */
> + :"rcx", "r10", "r11", "cc"
> + );
> + /*
> + * glibc lists 'cc' as clobbered, so we might as
> + * well do it too. 'r11' and 'rcx' are clobbered
> + * by the 'syscall' instruction itself. 'r8' and
> + * 'r9' are clobbered by the clone, but that
> + * thread will exit before getting back out to C.
> + */
> +
> + if (retval < 0) {
> + errno = -retval;
> + retval = -1;
> + }
> + return retval;
> +}
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