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Subject[PATCH v21 060/100] c/r: define s390-specific checkpoint-restart code
Date
From: Dan Smith <danms@us.ibm.com>

Implement the s390 arch-specific checkpoint/restart helpers. This
is on top of Oren Laadan's c/r code.

With these, I am able to checkpoint and restart simple programs as per
Oren's patch intro. While on x86 I never had to freeze a single task
to checkpoint it, on s390 I do need to. That is a prereq for consistent
snapshots (esp with multiple processes) anyway so I don't see that as
a problem.

Changelog [v21]:
- Do not include checkpoint_hdr.h explicitly
Changelog [v20]:
- [Serge Hallyn] save_access_regs for self-checkpoint
- [Serge Hallyn] send uses_interp=1 to arch_setup_additional_pages
Changelog [v19]:
- [Serge Hallyn] Move get_signal_to_deliver() up in do_signal
Changelog [v19-rc3]:
- [Serge Hallyn] Ue simpler test_task_thread to test current ti flags
- [Serge Hallyn] Fix 31-bit s390 checkpoint/restart wrappers
- [Serge Hallyn] Update sys_checkpoint (do_sys_checkpoint on all archs)
- [Oren Laadan] Move checkpoint.c from arch/s390/mm->arch/s390/kernel
Changelog [v19-rc1]:
- [Matt Helsley] Add cpp definitions for enums
Changelog:
Jun 15:
. Fix checkpoint and restart compat wrappers
May 28:
. Export asm/checkpoint_hdr.h to userspace
. Define CKPT_ARCH_ID for S390
Apr 11:
. Introduce ckpt_arch_vdso()
Feb 27:
. Add checkpoint_s390.h
. Fixed up save and restore of PSW, with the non-address bits
properly masked out
Feb 25:
. Make checkpoint_hdr.h safe for inclusion in userspace
. Replace comment about vsdo code
. Add comment about restoring access registers
. Write and read an empty ckpt_hdr_head_arch record to appease
code (mktree) that expects it to be there
. Utilize NUM_CKPT_WORDS in checkpoint_hdr.h
Feb 24:
. Use CKPT_COPY() to unify the un/loading of cpu and mm state
. Fix fprs definition in ckpt_hdr_cpu
. Remove debug WARN_ON() from checkpoint.c
Feb 23:
. Macro-ize the un/packing of trace flags
. Fix the crash when externally-linked
. Break out the restart functions into restart.c
. Remove unneeded s390_enable_sie() call
Jan 30:
. Switched types in ckpt_hdr_cpu to __u64 etc.
(Per Oren suggestion)
. Replaced direct inclusion of structs in
ckpt_hdr_cpu with the struct members.
(Per Oren suggestion)
. Also ended up adding a bunch of new things
into restart (mm_segment, ksp, etc) in vain
attempt to get code using fpu to not segfault
after restart.

Cc: linux-s390@vger.kernel.org
Signed-off-by: Serge E. Hallyn <serue@us.ibm.com>
Signed-off-by: Dan Smith <danms@us.ibm.com>
Acked-by: Oren Laadan <orenl@cs.columbia.edu>
---
arch/s390/include/asm/Kbuild | 1 +
arch/s390/include/asm/checkpoint_hdr.h | 98 ++++++++++++
arch/s390/include/asm/thread_info.h | 2 +
arch/s390/include/asm/unistd.h | 4 +-
arch/s390/kernel/Makefile | 1 +
arch/s390/kernel/checkpoint.c | 254 ++++++++++++++++++++++++++++++++
arch/s390/kernel/compat_wrapper.S | 16 ++
arch/s390/kernel/process.c | 19 +++
arch/s390/kernel/signal.c | 16 ++
arch/s390/kernel/syscalls.S | 2 +
arch/s390/mm/Makefile | 1 +
arch/s390/mm/checkpoint_s390.h | 23 +++
include/linux/checkpoint_hdr.h | 3 +
mm/mmap.c | 9 +-
14 files changed, 447 insertions(+), 2 deletions(-)
create mode 100644 arch/s390/include/asm/checkpoint_hdr.h
create mode 100644 arch/s390/kernel/checkpoint.c
create mode 100644 arch/s390/mm/checkpoint_s390.h

diff --git a/arch/s390/include/asm/Kbuild b/arch/s390/include/asm/Kbuild
index 63a2341..3282a6e 100644
--- a/arch/s390/include/asm/Kbuild
+++ b/arch/s390/include/asm/Kbuild
@@ -8,6 +8,7 @@ header-y += ucontext.h
header-y += vtoc.h
header-y += zcrypt.h
header-y += chsc.h
+header-y += checkpoint_hdr.h

unifdef-y += cmb.h
unifdef-y += debug.h
diff --git a/arch/s390/include/asm/checkpoint_hdr.h b/arch/s390/include/asm/checkpoint_hdr.h
new file mode 100644
index 0000000..e3312c0
--- /dev/null
+++ b/arch/s390/include/asm/checkpoint_hdr.h
@@ -0,0 +1,98 @@
+#ifndef __ASM_S390_CKPT_HDR_H
+#define __ASM_S390_CKPT_HDR_H
+/*
+ * Checkpoint/restart - architecture specific headers s/390
+ *
+ * Copyright IBM Corp. 2009
+ *
+ * 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.
+ */
+
+#ifndef _CHECKPOINT_CKPT_HDR_H_
+#error asm/checkpoint_hdr.h included directly
+#endif
+
+#include <linux/types.h>
+#include <asm/ptrace.h>
+
+#ifdef __KERNEL__
+#include <asm/processor.h>
+#endif
+
+#ifdef CONFIG_64BIT
+#define CKPT_ARCH_ID CKPT_ARCH_S390X
+/* else - if we ever support 32bit - CKPT_ARCH_S390 */
+#endif
+
+/*
+ * Notes
+ * NUM_GPRS defined in <asm/ptrace.h> to be 16
+ * NUM_FPRS defined in <asm/ptrace.h> to be 16
+ * NUM_APRS defined in <asm/ptrace.h> to be 16
+ * NUM_CR_WORDS defined in <asm/ptrace.h> to be 3
+ * but is not yet in glibc headers.
+ */
+
+#ifndef NUM_CR_WORDS
+#define NUM_CR_WORDS 3
+#endif
+
+struct ckpt_hdr_cpu {
+ struct ckpt_hdr h;
+ __u64 args[1];
+ __u64 gprs[NUM_GPRS];
+ __u64 orig_gpr2;
+ __u16 svcnr;
+ __u16 ilc;
+ __u32 acrs[NUM_ACRS];
+ __u64 ieee_instruction_pointer;
+
+ /* psw_t */
+ __u64 psw_t_mask;
+ __u64 psw_t_addr;
+
+ /* s390_fp_regs_t */
+ __u32 fpc;
+ union {
+ float f;
+ double d;
+ __u64 ui;
+ struct {
+ __u32 fp_hi;
+ __u32 fp_lo;
+ } fp;
+ } fprs[NUM_FPRS];
+
+ /* per_struct */
+ __u64 per_control_regs[NUM_CR_WORDS];
+ __u64 starting_addr;
+ __u64 ending_addr;
+ __u64 address;
+ __u16 perc_atmid;
+ __u8 access_id;
+ __u8 single_step;
+ __u8 instruction_fetch;
+};
+
+struct ckpt_hdr_thread {
+ struct ckpt_hdr h;
+ __u64 thread_info_flags;
+};
+
+struct ckpt_hdr_mm_context {
+ struct ckpt_hdr h;
+ unsigned long vdso_base;
+ int noexec;
+ int has_pgste;
+ int alloc_pgste;
+ unsigned long asce_bits;
+ unsigned long asce_limit;
+};
+
+struct ckpt_hdr_header_arch {
+ struct ckpt_hdr h;
+};
+
+#endif /* __ASM_S390_CKPT_HDR__H */
diff --git a/arch/s390/include/asm/thread_info.h b/arch/s390/include/asm/thread_info.h
index 34f0873..60f932e 100644
--- a/arch/s390/include/asm/thread_info.h
+++ b/arch/s390/include/asm/thread_info.h
@@ -99,6 +99,7 @@ static inline struct thread_info *current_thread_info(void)
#define TIF_MEMDIE 18
#define TIF_RESTORE_SIGMASK 19 /* restore signal mask in do_signal() */
#define TIF_FREEZE 20 /* thread is freezing for suspend */
+#define TIF_SIG_RESTARTBLOCK 23 /* restart must set TIF_RESTART_SVC */

#define _TIF_NOTIFY_RESUME (1<<TIF_NOTIFY_RESUME)
#define _TIF_RESTORE_SIGMASK (1<<TIF_RESTORE_SIGMASK)
@@ -114,6 +115,7 @@ static inline struct thread_info *current_thread_info(void)
#define _TIF_POLLING_NRFLAG (1<<TIF_POLLING_NRFLAG)
#define _TIF_31BIT (1<<TIF_31BIT)
#define _TIF_FREEZE (1<<TIF_FREEZE)
+#define _TIF_SIG_RESTARTBLOCK (1<<TIF_SIG_RESTARTBLOCK)

#endif /* __KERNEL__ */

diff --git a/arch/s390/include/asm/unistd.h b/arch/s390/include/asm/unistd.h
index ff13be1..79a4178 100644
--- a/arch/s390/include/asm/unistd.h
+++ b/arch/s390/include/asm/unistd.h
@@ -270,7 +270,9 @@
#define __NR_rt_tgsigqueueinfo 330
#define __NR_perf_event_open 331
#define __NR_eclone 332
-#define NR_syscalls 333
+#define __NR_checkpoint 333
+#define __NR_restart 334
+#define NR_syscalls 335

/*
* There are some system calls that are not present on 64 bit, some
diff --git a/arch/s390/kernel/Makefile b/arch/s390/kernel/Makefile
index 64230bc..b472855 100644
--- a/arch/s390/kernel/Makefile
+++ b/arch/s390/kernel/Makefile
@@ -36,6 +36,7 @@ obj-$(CONFIG_SMP) += smp.o topology.o
obj-$(CONFIG_SMP) += $(if $(CONFIG_64BIT),switch_cpu64.o, \
switch_cpu.o)
obj-$(CONFIG_HIBERNATION) += suspend.o swsusp_asm64.o
+obj-$(CONFIG_CHECKPOINT) += checkpoint.o
obj-$(CONFIG_AUDIT) += audit.o
compat-obj-$(CONFIG_AUDIT) += compat_audit.o
obj-$(CONFIG_COMPAT) += compat_linux.o compat_signal.o \
diff --git a/arch/s390/kernel/checkpoint.c b/arch/s390/kernel/checkpoint.c
new file mode 100644
index 0000000..c0de4cd
--- /dev/null
+++ b/arch/s390/kernel/checkpoint.c
@@ -0,0 +1,254 @@
+/*
+ * Checkpoint/restart - architecture specific support for s390
+ *
+ * Copyright IBM Corp. 2009
+ *
+ * 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/kernel.h>
+#include <asm/system.h>
+#include <asm/pgtable.h>
+#include <asm/elf.h>
+#include <asm/unistd.h>
+
+#include <linux/checkpoint.h>
+
+/**************************************************************************
+ * Checkpoint
+ */
+
+static void s390_copy_regs(int op, struct ckpt_hdr_cpu *h,
+ struct task_struct *t)
+{
+ struct pt_regs *regs = task_pt_regs(t);
+ struct thread_struct *thr = &t->thread;
+
+ /* Save the whole PSW to facilitate forensic debugging, but only
+ * restore the address portion to avoid letting userspace do
+ * bad things by manipulating its value.
+ */
+ if (op == CKPT_CPT) {
+ CKPT_COPY(op, h->psw_t_addr, regs->psw.addr);
+ } else {
+ regs->psw.addr &= ~PSW_ADDR_INSN;
+ regs->psw.addr |= h->psw_t_addr;
+ }
+
+ CKPT_COPY(op, h->args[0], regs->args[0]);
+ CKPT_COPY(op, h->orig_gpr2, regs->orig_gpr2);
+ CKPT_COPY(op, h->svcnr, regs->svcnr);
+ CKPT_COPY(op, h->ilc, regs->ilc);
+ CKPT_COPY(op, h->ieee_instruction_pointer,
+ thr->ieee_instruction_pointer);
+ CKPT_COPY(op, h->psw_t_mask, regs->psw.mask);
+ CKPT_COPY(op, h->fpc, thr->fp_regs.fpc);
+ CKPT_COPY(op, h->starting_addr, thr->per_info.starting_addr);
+ CKPT_COPY(op, h->ending_addr, thr->per_info.ending_addr);
+ CKPT_COPY(op, h->address, thr->per_info.lowcore.words.address);
+ CKPT_COPY(op, h->perc_atmid, thr->per_info.lowcore.words.perc_atmid);
+ CKPT_COPY(op, h->access_id, thr->per_info.lowcore.words.access_id);
+ CKPT_COPY(op, h->single_step, thr->per_info.single_step);
+ CKPT_COPY(op, h->instruction_fetch, thr->per_info.instruction_fetch);
+
+ CKPT_COPY_ARRAY(op, h->gprs, regs->gprs, NUM_GPRS);
+ /*
+ * for checkpoint in process context (from within a container),
+ * the actual syscall is taking place at this very moment; so
+ * we (optimistically) subtitute the future return value (0) of
+ * this syscall into the orig_eax, so that upon restart it will
+ * succeed (or it will endlessly retry checkpoint...)
+ */
+ if (op == CKPT_CPT && t == current) {
+ BUG_ON(h->gprs[2] < 0);
+ h->gprs[2] = 0;
+ }
+
+ /*
+ * if a checkpoint was taken while interrupted from a restartable
+ * syscall, then treat this as though signr==0 (since we did not
+ * handle the signal) and finish the last part of do_signal
+ */
+ if (op == CKPT_RST && test_thread_flag(TIF_SIG_RESTARTBLOCK)) {
+ regs->gprs[2] = __NR_restart_syscall;
+ set_thread_flag(TIF_RESTART_SVC);
+ clear_thread_flag(TIF_SIG_RESTARTBLOCK);
+ }
+
+ CKPT_COPY_ARRAY(op, h->fprs, thr->fp_regs.fprs, NUM_FPRS);
+ if (op == CKPT_CPT && t == current)
+ save_access_regs(h->acrs);
+ else
+ CKPT_COPY_ARRAY(op, h->acrs, thr->acrs, NUM_ACRS);
+ CKPT_COPY_ARRAY(op, h->per_control_regs,
+ thr->per_info.control_regs.words.cr, NUM_CR_WORDS);
+}
+
+static void s390_mm(int op, struct ckpt_hdr_mm_context *h,
+ struct mm_struct *mm)
+{
+ CKPT_COPY(op, h->noexec, mm->context.noexec);
+ CKPT_COPY(op, h->has_pgste, mm->context.has_pgste);
+ CKPT_COPY(op, h->alloc_pgste, mm->context.alloc_pgste);
+ CKPT_COPY(op, h->asce_bits, mm->context.asce_bits);
+ CKPT_COPY(op, h->asce_limit, mm->context.asce_limit);
+}
+
+int checkpoint_thread(struct ckpt_ctx *ctx, struct task_struct *t)
+{
+ struct ckpt_hdr_thread *h;
+ int ret;
+
+ /* we will eventually support this, as we do on x86-64 */
+ if (test_tsk_thread_flag(t, TIF_31BIT)) {
+ ckpt_err(ctx, -EINVAL, "checkpoint of 31-bit task\n");
+ return -EINVAL;
+ }
+
+ h = ckpt_hdr_get_type(ctx, sizeof(*h), CKPT_HDR_THREAD);
+ if (!h)
+ return -ENOMEM;
+
+ h->thread_info_flags = task_thread_info(t)->flags;
+ ret = ckpt_write_obj(ctx, &h->h);
+ ckpt_hdr_put(ctx, h);
+
+ return ret;
+}
+
+/* dump the cpu state and registers of a given task */
+int checkpoint_cpu(struct ckpt_ctx *ctx, struct task_struct *t)
+{
+ struct ckpt_hdr_cpu *h;
+ int ret;
+
+ h = ckpt_hdr_get_type(ctx, sizeof(*h), CKPT_HDR_CPU);
+ if (!h)
+ return -ENOMEM;
+
+ s390_copy_regs(CKPT_CPT, h, t);
+
+ ret = ckpt_write_obj(ctx, (struct ckpt_hdr *) h);
+ ckpt_hdr_put(ctx, h);
+
+ return ret;
+}
+
+/* Write an empty header since it is assumed to be there */
+int checkpoint_write_header_arch(struct ckpt_ctx *ctx)
+{
+ struct ckpt_hdr_header_arch *h;
+ int ret;
+
+ h = ckpt_hdr_get_type(ctx, sizeof(*h), CKPT_HDR_HEADER_ARCH);
+ if (!h)
+ return -ENOMEM;
+
+ ret = ckpt_write_obj(ctx, (struct ckpt_hdr *) h);
+ ckpt_hdr_put(ctx, h);
+
+ return ret;
+}
+
+int checkpoint_mm_context(struct ckpt_ctx *ctx, struct mm_struct *mm)
+{
+ struct ckpt_hdr_mm_context *h;
+ int ret;
+
+ h = ckpt_hdr_get_type(ctx, sizeof(*h), CKPT_HDR_MM_CONTEXT);
+ if (!h)
+ return -ENOMEM;
+
+ s390_mm(CKPT_CPT, h, mm);
+
+ ret = ckpt_write_obj(ctx, (struct ckpt_hdr *) h);
+ ckpt_hdr_put(ctx, h);
+
+ return ret;
+}
+
+/**************************************************************************
+ * Restart
+ */
+
+int restore_thread(struct ckpt_ctx *ctx)
+{
+ struct ckpt_hdr_thread *h;
+
+ /* a 31-bit task cannot call sys_restart right now */
+ if (test_thread_flag(TIF_31BIT)) {
+ ckpt_err(ctx, -EINVAL, "restart from 31-bit task\n");
+ return -EINVAL;
+ }
+
+ h = ckpt_read_obj_type(ctx, sizeof(*h), CKPT_HDR_THREAD);
+ if (IS_ERR(h))
+ return PTR_ERR(h);
+
+ /*
+ * If we were checkpointed while do_signal() interrupted a
+ * syscall with restart blocks, then we have some cleanup to
+ * do at end of restart, in order to finish our pretense of
+ * having handled signr==0. (See last part of do_signal).
+ *
+ * We can't set gprs[2] here bc we haven't copied registers
+ * yet, that happens later in restore_cpu(). So re-set the
+ * TIF_SIG_RESTARTBLOCK thread flag so we can detect it
+ * at restore_cpu()->s390_copy_regs() and do the right thing.
+ */
+ if (h->thread_info_flags & _TIF_SIG_RESTARTBLOCK)
+ set_thread_flag(TIF_SIG_RESTARTBLOCK);
+
+ ckpt_hdr_put(ctx, h);
+
+ return 0;
+}
+
+int restore_cpu(struct ckpt_ctx *ctx)
+{
+ struct ckpt_hdr_cpu *h;
+
+ h = ckpt_read_obj_type(ctx, sizeof(*h), CKPT_HDR_CPU);
+ if (IS_ERR(h))
+ return PTR_ERR(h);
+
+ s390_copy_regs(CKPT_RST, h, current);
+
+ /* s390 does not restore the access registers after a syscall,
+ * but does on a task switch. Since we're switching tasks (in
+ * a way), we need to replicate that behavior here.
+ */
+ restore_access_regs(h->acrs);
+
+ ckpt_hdr_put(ctx, h);
+ return 0;
+}
+
+int restore_read_header_arch(struct ckpt_ctx *ctx)
+{
+ struct ckpt_hdr_header_arch *h;
+
+ h = ckpt_read_obj_type(ctx, sizeof(*h), CKPT_HDR_HEADER_ARCH);
+ if (IS_ERR(h))
+ return PTR_ERR(h);
+
+ ckpt_hdr_put(ctx, h);
+ return 0;
+}
+
+
+int restore_mm_context(struct ckpt_ctx *ctx, struct mm_struct *mm)
+{
+ struct ckpt_hdr_mm_context *h;
+
+ h = ckpt_read_obj_type(ctx, sizeof(*h), CKPT_HDR_MM_CONTEXT);
+ if (IS_ERR(h))
+ return PTR_ERR(h);
+
+ s390_mm(CKPT_RST, h, mm);
+
+ ckpt_hdr_put(ctx, h);
+ return 0;
+}
diff --git a/arch/s390/kernel/compat_wrapper.S b/arch/s390/kernel/compat_wrapper.S
index b7bedfa..d57e5e0 100644
--- a/arch/s390/kernel/compat_wrapper.S
+++ b/arch/s390/kernel/compat_wrapper.S
@@ -1861,3 +1861,19 @@ sys32_execve_wrapper:
llgtr %r3,%r3 # compat_uptr_t *
llgtr %r4,%r4 # compat_uptr_t *
jg sys32_execve # branch to system call
+
+ .globl sys_checkpoint_wrapper
+sys_checkpoint_wrapper:
+ lgfr %r2,%r2 # pid_t
+ lgfr %r3,%r3 # int
+ llgfr %r4,%r4 # unsigned long
+ lgfr %r5,%r5 # int
+ jg sys_checkpoint
+
+ .globl sys_restart_wrapper
+sys_restart_wrapper:
+ lgfr %r2,%r2 # pid_t
+ lgfr %r3,%r3 # int
+ llgfr %r4,%r4 # unsigned long
+ lgfr %r5,%r5 # int
+ jg sys_restart
diff --git a/arch/s390/kernel/process.c b/arch/s390/kernel/process.c
index 15f5719..efc7e8a 100644
--- a/arch/s390/kernel/process.c
+++ b/arch/s390/kernel/process.c
@@ -32,6 +32,7 @@
#include <linux/kernel_stat.h>
#include <linux/syscalls.h>
#include <linux/compat.h>
+#include <linux/checkpoint.h>
#include <asm/compat.h>
#include <asm/uaccess.h>
#include <asm/pgtable.h>
@@ -241,11 +242,29 @@ SYSCALL_DEFINE4(clone, unsigned long, newsp, unsigned long, clone_flags,
}

#ifdef CONFIG_CHECKPOINT
+SYSCALL_DEFINE4(checkpoint, pid_t, pid, int, fd, unsigned long, flags,
+ int, logfd)
+{
+ return do_sys_checkpoint(pid, fd, flags, logfd);
+}
+
SYSCALL_DEFINE4(restart, pid_t, pid, int, fd, unsigned long, flags,
int, logfd)
{
return do_sys_restart(pid, fd, flags, logfd);
}
+#else
+SYSCALL_DEFINE4(checkpoint, pid_t, pid, int, fd, unsigned long, flags,
+ int, logfd)
+{
+ return -ENOSYS;
+}
+
+SYSCALL_DEFINE4(restart, pid_t, pid, int, fd, unsigned long, flags,
+ int, logfd)
+{
+ return -ENOSYS;
+}
#endif

SYSCALL_DEFINE4(eclone, unsigned int, flags_low, struct clone_args __user *,
diff --git a/arch/s390/kernel/signal.c b/arch/s390/kernel/signal.c
index 6289945..83425b1 100644
--- a/arch/s390/kernel/signal.c
+++ b/arch/s390/kernel/signal.c
@@ -459,6 +459,16 @@ void do_signal(struct pt_regs *regs)
break;
case -ERESTART_RESTARTBLOCK:
regs->gprs[2] = -EINTR;
+ /*
+ * This condition is the only one which requires
+ * special care after handling a signr==0. So if
+ * we get frozen and checkpointed at the
+ * get_signal_to_deliver() below, then we need
+ * to convey this condition to sys_restart() so it
+ * can set the restored thread up to run the restart
+ * block.
+ */
+ set_thread_flag(TIF_SIG_RESTARTBLOCK);
}
regs->svcnr = 0; /* Don't deal with this again. */
}
@@ -467,6 +477,12 @@ void do_signal(struct pt_regs *regs)
the debugger may change all our registers ... */
signr = get_signal_to_deliver(&info, &ka, regs, NULL);

+ /*
+ * we won't get frozen past this so clear the thread flag hinting
+ * to sys_restart that TIF_RESTART_SVC must be set.
+ */
+ clear_thread_flag(TIF_SIG_RESTARTBLOCK);
+
/* Depending on the signal settings we may need to revert the
decision to restart the system call. */
if (signr > 0 && regs->psw.addr == restart_addr) {
diff --git a/arch/s390/kernel/syscalls.S b/arch/s390/kernel/syscalls.S
index 08eab1d..9f1f28e 100644
--- a/arch/s390/kernel/syscalls.S
+++ b/arch/s390/kernel/syscalls.S
@@ -341,3 +341,5 @@ SYSCALL(sys_pwritev,sys_pwritev,compat_sys_pwritev_wrapper)
SYSCALL(sys_rt_tgsigqueueinfo,sys_rt_tgsigqueueinfo,compat_sys_rt_tgsigqueueinfo_wrapper) /* 330 */
SYSCALL(sys_perf_event_open,sys_perf_event_open,sys_perf_event_open_wrapper)
SYSCALL(sys_eclone,sys_eclone,sys_eclone_wrapper)
+SYSCALL(sys_checkpoint,sys_checkpoint,sys_checkpoint_wrapper)
+SYSCALL(sys_restart,sys_restart,sys_restart_wrapper)
diff --git a/arch/s390/mm/Makefile b/arch/s390/mm/Makefile
index eec0544..359a3bc 100644
--- a/arch/s390/mm/Makefile
+++ b/arch/s390/mm/Makefile
@@ -6,3 +6,4 @@ obj-y := init.o fault.o extmem.o mmap.o vmem.o pgtable.o maccess.o \
page-states.o
obj-$(CONFIG_CMM) += cmm.o
obj-$(CONFIG_HUGETLB_PAGE) += hugetlbpage.o
+obj-$(CONFIG_PAGE_STATES) += page-states.o
diff --git a/arch/s390/mm/checkpoint_s390.h b/arch/s390/mm/checkpoint_s390.h
new file mode 100644
index 0000000..c3bf24d
--- /dev/null
+++ b/arch/s390/mm/checkpoint_s390.h
@@ -0,0 +1,23 @@
+/*
+ * Checkpoint/restart - architecture specific support for s390
+ *
+ * Copyright IBM Corp. 2009
+ *
+ * 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.
+ */
+
+#ifndef _S390_CHECKPOINT_H
+#define _S390_CHECKPOINT_H
+
+#include <linux/checkpoint_hdr.h>
+#include <linux/sched.h>
+#include <linux/mm_types.h>
+
+extern void checkpoint_s390_regs(int op, struct ckpt_hdr_cpu *h,
+ struct task_struct *t);
+extern void checkpoint_s390_mm(int op, struct ckpt_hdr_mm_context *h,
+ struct mm_struct *mm);
+
+#endif /* _S390_CHECKPOINT_H */
diff --git a/include/linux/checkpoint_hdr.h b/include/linux/checkpoint_hdr.h
index 3ae2d7d..8f81da1 100644
--- a/include/linux/checkpoint_hdr.h
+++ b/include/linux/checkpoint_hdr.h
@@ -133,10 +133,13 @@ enum {

/* architecture */
enum {
+ /* do not change order (will break ABI) */
CKPT_ARCH_X86_32 = 1,
#define CKPT_ARCH_X86_32 CKPT_ARCH_X86_32
CKPT_ARCH_X86_64,
#define CKPT_ARCH_X86_64 CKPT_ARCH_X86_64
+ CKPT_ARCH_S390X,
+#define CKPT_ARCH_S390X CKPT_ARCH_S390X
};

/* shared objrects (objref) */
diff --git a/mm/mmap.c b/mm/mmap.c
index ddbe589..4b36b2a 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -2495,7 +2495,14 @@ int special_mapping_restore(struct ckpt_ctx *ctx,
ret = syscall32_setup_pages(NULL, h->vm_start, 0);
else
#endif
- ret = arch_setup_additional_pages(NULL, h->vm_start, 0);
+ /*
+ * Pass uses_interp=1 to arch_setup_additional_pages because
+ * s390 won't set up vdso if it is 0. Here it's safe to assume
+ * that there is a vdso in the checkpoint image, and therefore
+ * the checkpointed program was dynamically linked. The other
+ * architectures ignore uses_interp altogether.
+ */
+ ret = arch_setup_additional_pages(NULL, h->vm_start, 1);
#endif

return ret;
--
1.6.3.3


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