[Devel] Re: [PATCH] ARM: Added user space support for c/r on ARM
Christoffer Dall
christofferdall at christofferdall.dk
Wed Apr 28 00:29:12 PDT 2010
Hi Matt.
Thanks for the feedback. I have changed the path according to your comments
and am attaching it below.
- Let me know if I need to adjust my patch before inclusion with respect to
the s/clone_with_pids// later.
- Much better with the 'local SYS_NR_DEF_REGEX' in get_unistd_regex().
Thanks.
- I pondered about inserting arch-specific code when printing the header
content, and thought about a file function like add_arch_syscall_base()
but it seems rhather synthetic as I think ARM is the only possible
architecture, which would use it. Instead, I added whitespace around the
line as you suggest.
- I agree regarding the make variables - it was simply a glitch. I
adjusted the assignment in both Makefile and test/Makefile.
Thanks,
Christoffer
diff --git a/Makefile b/Makefile
index 6c9ff93..37ed40a 100644
--- a/Makefile
+++ b/Makefile
@@ -18,6 +18,13 @@ CR_OBJS = checkpoint.o checkpoint-main.o restart.o restart-main.o
# detect architecture (for eclone)
SUBARCH ?= $(patsubst i%86,x86_32,$(shell uname -m))
+# handle cross-compilation
+AR := ${CROSS_COMPILE}ar
+AS := ${CROSS_COMPILE}as
+CC := ${CROSS_COMPILE}gcc
+CPP := ${CROSS_COMPILE}cpp
+LD := ${CROSS_COMPILE}ld
+
# compile with debug ?
DEBUG = -DCHECKPOINT_DEBUG
@@ -77,6 +84,11 @@ ASFLAGS += -m64
$(LIB_ECLONE): clone_$(SUBARCH)_.o
endif
+# also on ARM, need also assembly file
+ifeq ($(SUBARCH),arm)
+$(LIB_ECLONE): eclone_$(SUBARCH)_.o
+endif
+
# ckptinfo dependencies
ckptinfo: ckptinfo_types.o
diff --git a/clone.h b/clone.h
index 3569a45..b6b18ce 100644
--- a/clone.h
+++ b/clone.h
@@ -25,6 +25,14 @@
# define __NR_unshare 303
#elif __powerpc__
# define __NR_unshare 282
+#elif __arm__
+# define __NR_OABI_SYSCALL_BASE 0x900000
+# if defined(__thumb__) || defined(__ARM_EABI__)
+# define __NR_SYSCALL_BASE 0
+# else
+# define __NR_SYSCALL_BASE __NR_OABI_SYSCALL_BASE
+# endif
+# define __NR_unshare (__NR_SYSCALL_BASE+337)
#else
# error "Architecture not supported"
#endif
diff --git a/clone_arm.c b/clone_arm.c
new file mode 100644
index 0000000..b62b4ad
--- /dev/null
+++ b/clone_arm.c
@@ -0,0 +1,79 @@
+/*
+ * clone_arm.c: support for eclone() on ARM
+ *
+ * Author: Christoffer Dall <christofferdall at christofferdall.dk>
+ *
+ * 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 <stdio.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"
+
+extern int __eclone(int clone_flags_low,
+ struct clone_args *clone_args,
+ unsigned int args_size,
+ pid_t *pids);
+
+static unsigned long get_stack_pointer(unsigned long base, unsigned long size)
+{
+ size_t page_size = sysconf(_SC_PAGESIZE);
+ return (base + size - page_size) - 1;
+}
+
+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 newpid;
+ void **sp = NULL;
+
+ if (!fn) {
+ fprintf(stderr, "Please provide a valid function pointer "
+ "for the child process.\n");
+ return -1;
+ }
+
+ if (clone_args->child_stack) {
+ sp = (void **)get_stack_pointer(clone_args->child_stack,
+ clone_args->child_stack_size);
+ *--sp = fn_arg;
+ *--sp = fn;
+ } else {
+ fprintf(stderr, "The ARM architecture requires a valid child "
+ "stack. clon_args->child_stack was 0.\n");
+ return -1;
+ }
+
+
+ my_args = *clone_args;
+ my_args.child_stack = (unsigned long long)sp;
+ my_args.child_stack_size = 0;
+
+ newpid = __eclone(clone_flags_low,
+ &my_args,
+ sizeof(my_args),
+ pids);
+
+ if (newpid < 0) {
+ errno = -newpid;
+ newpid = -1;
+ }
+
+ return newpid;
+}
diff --git a/eclone_arm_.S b/eclone_arm_.S
new file mode 100644
index 0000000..0f71d0f
--- /dev/null
+++ b/eclone_arm_.S
@@ -0,0 +1,86 @@
+/*
+ * eclone_arm_.S: ARM support for eclone()
+ *
+ * Author: Christoffer Dall <christofferdall at christofferdall.dk>
+ *
+ * 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 _ERRNO_H 1
+#include <bits/errno.h>
+#include <asm/unistd.h>
+
+
+#define CLONE_VM 0x00000100
+#define CLONE_THREAD 0x00010000
+
+#ifndef __NR_eclone
+#define __NR_eclone 366
+#endif
+
+/*
+ * Implements the following system call wrapper:
+ *
+ * extern int __eclone(int clone_flags_low,
+ * struct clone_args *clone_args,
+ * pid_t *pids);
+ *
+ * The system call wrapper and the system call themselves have slightly
+ * different layouts and the following transformation takes place in
+ * the code below:
+ *
+ */
+
+ .text
+ .align 4
+ .globl __eclone
+ .type __eclone,%function
+__eclone:
+ @ save flags
+ mov ip, r0
+
+ @ do the system call
+#ifdef __ARM_EABI__
+ str r7, [sp, #-4]!
+ ldr r7, =__NR_eclone
+ swi 0x0
+#else
+ swi __NR_eclone
+#endif
+ cmp r0, #0
+ beq 1f
+#ifdef __ARM_EABI__
+ ldr r7, [sp], #4
+#endif
+ @ return to caller
+ bx lr
+
+1:
+ tst ip, #CLONE_THREAD
+ bne 3f
+ mov r0, #0xffff0fff
+ mov lr, pc
+ sub pc, r0, #31
+ mov r1, r0
+ tst ip, #CLONE_VM
+ movne r0, #-1
+#ifdef __ARM_EABI__
+ ldr r7, =__NR_getpid
+ swieq 0x0
+#else
+ swieq __NR_getpid
+#endif
+ str r0, [r1, #-1108]
+ str r0, [r1, #-1112]
+3:
+ @ pick the function arg and call address off the stack and execute
+ ldr r0, [sp, #4]
+ mov lr, pc
+ ldr pc, [sp], #8
+
+ @ and we are done, passing the return value through r0
+ @b PLTJMP(HIDDEN_JUMPTARGET(_exit))
+ b _exit
+
diff --git a/include/asm-arm/checkpoint_hdr.h b/include/asm-arm/checkpoint_hdr.h
new file mode 100644
index 0000000..9295f85
--- /dev/null
+++ b/include/asm-arm/checkpoint_hdr.h
@@ -0,0 +1,55 @@
+/*
+ * Generated by extract-headers.sh.
+ */
+#ifndef __ASM_ARM_CHECKPOINT_HDR_H_
+#define __ASM_ARM_CHECKPOINT_HDR_H_
+
+/*
+ * Checkpoint/restart - architecture specific headers ARM
+ *
+ * Copyright (C) 2008-2010 Oren Laadan
+ * Copyright (C) 2010 Christoffer Dall
+ *
+ * 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.
+ */
+
+#include <linux/types.h>
+
+/* ARM structure seen from kernel/userspace */
+
+#define CKPT_ARCH_ID CKPT_ARCH_ARM
+
+/* arch dependent constants */
+#define CKPT_ARCH_NSIG 64
+#define CKPT_TTY_NCC 8
+
+struct ckpt_hdr_header_arch {
+ struct ckpt_hdr h;
+ __u32 cpu_architecture;
+ __u8 mmu; /* Checkpointed on mmu system */
+ __u8 aeabi; /* Checkpointed on AEABI kernel */
+ __u8 oabi_compat; /* Checkpointed on OABI compat. system */
+} __attribute__((aligned(8)));
+
+struct ckpt_hdr_thread {
+ struct ckpt_hdr h;
+ __u32 syscall;
+ __u32 tp_value;
+ __u32 thumbee_state;
+} __attribute__((aligned(8)));
+
+struct ckpt_hdr_cpu {
+ struct ckpt_hdr h;
+ __u32 uregs[18];
+} __attribute__((aligned(8)));
+
+struct ckpt_hdr_mm_context {
+ struct ckpt_hdr h;
+ __u32 end_brk;
+} __attribute__((aligned(8)));
+
+
+
+#endif /* __ASM_ARM_CHECKPOINT_HDR_H_ */
diff --git a/include/asm/checkpoint_hdr.h b/include/asm/checkpoint_hdr.h
index 859f58e..7f18e0e 100644
--- a/include/asm/checkpoint_hdr.h
+++ b/include/asm/checkpoint_hdr.h
@@ -3,7 +3,9 @@
*/
#ifndef __ASM_CHECKPOINT_HDR_H_
#define __ASM_CHECKPOINT_HDR_H_
-#if __powerpc__
+#if __arm__
+#include <asm-arm/checkpoint_hdr.h>
+#elif __powerpc__
#include <asm-powerpc/checkpoint_hdr.h>
#elif __s390x__
#include <asm-s390/checkpoint_hdr.h>
diff --git a/include/linux/checkpoint.h b/include/linux/checkpoint.h
index f6a6448..359023f 100644
--- a/include/linux/checkpoint.h
+++ b/include/linux/checkpoint.h
@@ -31,7 +31,25 @@
#define CHECKPOINT_FD_NONE -1
-#if __powerpc__
+#if __arm__
+
+# define __NR_OABI_SYSCALL_BASE 0x900000
+# if defined(__thumb__) || defined(__ARM_EABI__)
+# define __NR_SYSCALL_BASE 0
+# else
+# define __NR_SYSCALL_BASE __NR_OABI_SYSCALL_BASE
+# endif
+
+
+# ifndef __NR_checkpoint
+# define __NR_checkpoint (__NR_SYSCALL_BASE+367)
+# endif
+
+# ifndef __NR_restart
+# define __NR_restart (__NR_SYSCALL_BASE+368)
+# endif
+
+#elif __powerpc__
# ifndef __NR_checkpoint
# define __NR_checkpoint 324
diff --git a/include/linux/checkpoint_hdr.h b/include/linux/checkpoint_hdr.h
index 65d5256..214cd11 100644
--- a/include/linux/checkpoint_hdr.h
+++ b/include/linux/checkpoint_hdr.h
@@ -202,6 +202,8 @@ enum {
#define CKPT_ARCH_PPC32 CKPT_ARCH_PPC32
CKPT_ARCH_PPC64,
#define CKPT_ARCH_PPC64 CKPT_ARCH_PPC64
+ CKPT_ARCH_ARM,
+#define CKPT_ARCH_ARM CKPT_ARCH_ARM
};
/* shared objrects (objref) */
diff --git a/scripts/extract-headers.sh b/scripts/extract-headers.sh
index 8c8ae69..19f63b4 100755
--- a/scripts/extract-headers.sh
+++ b/scripts/extract-headers.sh
@@ -144,7 +144,27 @@ echo '#endif /* _CHECKPOINT_CKPT_HDR_H_ */' >> "${OUTPUT_INCLUDES}/linux/checkpo
# We use ARCH_COND to break up architecture-specific sections of the header.
#
ARCH_COND='#if'
-REGEX='[[:space:]]*#[[:space:]]*define[[:space:]]*__NR_(checkpoint|restart|clone_with_pids)[[:space:]]+[0-9]+'
+ARM_SYSCALL_BASE="# define __NR_OABI_SYSCALL_BASE 0x900000\n\
+# if defined(__thumb__) || defined(__ARM_EABI__)\n\
+# define __NR_SYSCALL_BASE 0\n\
+# else\n\
+# define __NR_SYSCALL_BASE __NR_OABI_SYSCALL_BASE\n\
+# endif\n"
+
+# Get the regular expression for the current architecture
+function get_unistd_regex()
+{
+ local SYS_NR_DEF_REGEX='[[:space:]]*#[[:space:]]*define[[:space:]]*__NR_(checkpoint|restart|clone_with_pids)[[:space:]]+'
+
+ case "$1" in
+ arm) echo -n "${SYS_NR_DEF_REGEX}"
+ echo -n '\(__NR_SYSCALL_BASE\+[[:space:]]*[0-9]*\)'
+ ;;
+ *) echo -n "${SYS_NR_DEF_REGEX}"'[0-9]+'
+ ;;
+ esac
+ return 0
+}
cat - <<-EOFOE
/*
@@ -160,11 +180,15 @@ do_cpp "${KERNELSRC}/include/linux/checkpoint.h" "_LINUX_CHECKPOINT_H_"
find "${KERNELSRC}/arch" -name 'unistd*.h' -print | sort | \
while read UNISTDH ; do
[ -n "${UNISTDH}" ] || continue
- grep -q -E "${REGEX}" "${UNISTDH}" || continue
KARCH=$(echo "${UNISTDH}" | sed -e 's|.*/arch/\([^/]\+\)/.*|\1|')
+ REGEX="$(get_unistd_regex "${KARCH}")"
+ grep -q -E "${REGEX}" "${UNISTDH}" || continue
WORDBITS=$(basename "${UNISTDH}" | sed -e 's/unistd_*\([[:digit:]]\+\)\.h/\1/')
CPPARCH="$(karch_to_cpparch "${KARCH}" "${WORDBITS}")"
echo -e "${ARCH_COND} __${CPPARCH}__\\n"
+
+ [ "${KARCH}" == "arm" ] && echo -e "${ARM_SYSCALL_BASE}\n"
+
grep -E "${REGEX}" "${UNISTDH}" | \
sed -e 's/^[ \t]*#[ \t]*define[ \t]*__NR_\([^ \t]\+\)[ \t]\+\([^ \t]\+\).*$/#\tifndef __NR_\1\n#\t\tdefine __NR_\1 \2\n#\tendif\n/'
ARCH_COND='#elif'
diff --git a/test/Makefile b/test/Makefile
index cad40e0..516eee8 100644
--- a/test/Makefile
+++ b/test/Makefile
@@ -1,3 +1,9 @@
+# handle cross-compilation
+AR = ${CROSS_COMPILE}ar
+AS = ${CROSS_COMPILE}as
+CC = ${CROSS_COMPILE}gcc
+CPP = ${CROSS_COMPILE}cpp
+LD = ${CROSS_COMPILE}ld
# extra warnings and fun
WARNS := -Wall -Wstrict-prototypes -Wno-trigraphs
--
1.5.6.5
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