Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755553AbZGVKWx (ORCPT ); Wed, 22 Jul 2009 06:22:53 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755538AbZGVKWw (ORCPT ); Wed, 22 Jul 2009 06:22:52 -0400 Received: from smtp161.dfw.emailsrvr.com ([67.192.241.161]:40236 "EHLO smtp161.dfw.emailsrvr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753601AbZGVKKX (ORCPT ); Wed, 22 Jul 2009 06:10:23 -0400 From: Oren Laadan To: Andrew Morton Cc: Linus Torvalds , containers@lists.linux-foundation.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-api@vger.kernel.org, Serge Hallyn , Dave Hansen , Ingo Molnar , "H. Peter Anvin" , Alexander Viro , Pavel Emelyanov , Alexey Dobriyan , Oren Laadan , Oren Laadan Subject: [RFC v17][PATCH 21/60] c/r: x86_32 support for checkpoint/restart Date: Wed, 22 Jul 2009 05:59:43 -0400 Message-Id: <1248256822-23416-22-git-send-email-orenl@librato.com> X-Mailer: git-send-email 1.6.0.4 In-Reply-To: <1248256822-23416-1-git-send-email-orenl@librato.com> References: <1248256822-23416-1-git-send-email-orenl@librato.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 24656 Lines: 944 Add logic to save and restore architecture specific state, including thread-specific state, CPU registers and FPU state. In addition, architecture capabilities are saved in an architecure specific extension of the header (ckpt_hdr_head_arch); Currently this includes only FPU capabilities. Currently only x86-32 is supported. Changelog[v17]: - Fix compilation for architectures that don't support checkpoint - Validate cpu registers and TLS descriptors on restart - Validate debug registers on restart - Export asm/checkpoint_hdr.h to userspace Changelog[v16]: - All objects are preceded by ckpt_hdr (TLS and xstate_buf) - Add architecture identifier to main header Changelog[v14]: - Use new interface ckpt_hdr_get/put() - Embed struct ckpt_hdr in struct ckpt_hdr... - Remove preempt_disable/enable() around init_fpu() and fix leak - Revert change to pr_debug(), back to ckpt_debug() - Move code related to task_struct to checkpoint/process.c Changelog[v12]: - A couple of missed calls to ckpt_hbuf_put() - Replace obsolete ckpt_debug() with pr_debug() Changelog[v9]: - Add arch-specific header that details architecture capabilities; split FPU restore to send capabilities only once. - Test for zero TLS entries in ckpt_write_thread() - Fix asm/checkpoint_hdr.h so it can be included from user-space Changelog[v7]: - Fix save/restore state of FPU Changelog[v5]: - Remove preempt_disable() when restoring debug registers Changelog[v4]: - Fix header structure alignment Changelog[v2]: - Pad header structures to 64 bits to ensure compatibility - Follow Dave Hansen's refactoring of the original post Signed-off-by: Oren Laadan --- arch/x86/include/asm/Kbuild | 1 + arch/x86/include/asm/checkpoint_hdr.h | 122 ++++++++ arch/x86/include/asm/ptrace.h | 5 + arch/x86/kernel/ptrace.c | 8 +- arch/x86/mm/Makefile | 2 + arch/x86/mm/checkpoint.c | 534 +++++++++++++++++++++++++++++++++ checkpoint/checkpoint.c | 7 +- checkpoint/process.c | 20 ++- checkpoint/restart.c | 6 + include/linux/checkpoint.h | 9 + include/linux/checkpoint_hdr.h | 16 +- 11 files changed, 722 insertions(+), 8 deletions(-) create mode 100644 arch/x86/include/asm/checkpoint_hdr.h create mode 100644 arch/x86/mm/checkpoint.c diff --git a/arch/x86/include/asm/Kbuild b/arch/x86/include/asm/Kbuild index 4a8e80c..f76cb6e 100644 --- a/arch/x86/include/asm/Kbuild +++ b/arch/x86/include/asm/Kbuild @@ -2,6 +2,7 @@ include include/asm-generic/Kbuild.asm header-y += boot.h header-y += bootparam.h +header-y += checkpoint_hdr.h header-y += debugreg.h header-y += ldt.h header-y += msr-index.h diff --git a/arch/x86/include/asm/checkpoint_hdr.h b/arch/x86/include/asm/checkpoint_hdr.h new file mode 100644 index 0000000..c5762fb --- /dev/null +++ b/arch/x86/include/asm/checkpoint_hdr.h @@ -0,0 +1,122 @@ +#ifndef __ASM_X86_CKPT_HDR_H +#define __ASM_X86_CKPT_HDR_H +/* + * Checkpoint/restart - architecture specific headers x86 + * + * Copyright (C) 2008-2009 Oren Laadan + * + * 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 + +/* + * To maintain compatibility between 32-bit and 64-bit architecture flavors, + * keep data 64-bit aligned: use padding for structure members, and use + * __attribute__((aligned (8))) for the entire structure. + * + * Quoting Arnd Bergmann: + * "This structure has an odd multiple of 32-bit members, which means + * that if you put it into a larger structure that also contains 64-bit + * members, the larger structure may get different alignment on x86-32 + * and x86-64, which you might want to avoid. I can't tell if this is + * an actual problem here. ... In this case, I'm pretty sure that + * sizeof(ckpt_hdr_task) on x86-32 is different from x86-64, since it + * will be 32-bit aligned on x86-32." + */ + +/* i387 structure seen from kernel/userspace */ +#ifdef __KERNEL__ +#include +#else +#include +#endif + +#ifdef CONFIG_X86_32 +#define CKPT_ARCH_ID CKPT_ARCH_X86_32 +#endif + +/* arch dependent header types */ +enum { + CKPT_HDR_CPU_FPU = 201, +}; + +struct ckpt_hdr_header_arch { + struct ckpt_hdr h; + /* FIXME: add HAVE_HWFP */ + __u16 has_fxsr; + __u16 has_xsave; + __u16 xstate_size; + __u16 _pading; +} __attribute__((aligned(8))); + +struct ckpt_hdr_thread { + struct ckpt_hdr h; + /* FIXME: restart blocks */ + __u32 thread_info_flags; + __u16 gdt_entry_tls_entries; + __u16 sizeof_tls_array; +} __attribute__((aligned(8))); + +/* designed to work for both x86_32 and x86_64 */ +struct ckpt_hdr_cpu { + struct ckpt_hdr h; + /* see struct pt_regs (x86_64) */ + __u64 r15; + __u64 r14; + __u64 r13; + __u64 r12; + __u64 bp; + __u64 bx; + __u64 r11; + __u64 r10; + __u64 r9; + __u64 r8; + __u64 ax; + __u64 cx; + __u64 dx; + __u64 si; + __u64 di; + __u64 orig_ax; + __u64 ip; + __u64 sp; + + __u64 flags; + + /* segment registers */ + __u64 fs; + __u64 gs; + + __u16 fsindex; + __u16 gsindex; + __u16 cs; + __u16 ss; + __u16 ds; + __u16 es; + + __u32 used_math; + + /* debug registers */ + __u64 debugreg0; + __u64 debugreg1; + __u64 debugreg2; + __u64 debugreg3; + __u64 debugreg6; + __u64 debugreg7; + + /* thread_xstate contents follow (if used_math) */ +} __attribute__((aligned(8))); + +#define CKPT_X86_SEG_NULL 0 +#define CKPT_X86_SEG_USER32_CS 1 +#define CKPT_X86_SEG_USER32_DS 2 +#define CKPT_X86_SEG_TLS 0x4000 /* 0100 0000 0000 00xx */ +#define CKPT_X86_SEG_LDT 0x8000 /* 100x xxxx xxxx xxxx */ + +#endif /* __ASM_X86_CKPT_HDR__H */ diff --git a/arch/x86/include/asm/ptrace.h b/arch/x86/include/asm/ptrace.h index 0f0d908..66b507b 100644 --- a/arch/x86/include/asm/ptrace.h +++ b/arch/x86/include/asm/ptrace.h @@ -242,6 +242,11 @@ extern void ptrace_bts_untrace(struct task_struct *tsk); #define arch_ptrace_untrace(tsk) ptrace_bts_untrace(tsk) #endif /* CONFIG_X86_PTRACE_BTS */ +extern int ptrace_check_debugreg(int _32bit, + unsigned long dr0, unsigned long dr1, + unsigned long dr2, unsigned long dr3, + unsigned long dr6, unsigned long dr7); + #endif /* __KERNEL__ */ #endif /* !__ASSEMBLY__ */ diff --git a/arch/x86/kernel/ptrace.c b/arch/x86/kernel/ptrace.c index 9b4cacf..3b434bd 100644 --- a/arch/x86/kernel/ptrace.c +++ b/arch/x86/kernel/ptrace.c @@ -466,10 +466,10 @@ static unsigned long ptrace_get_debugreg(struct task_struct *child, int n) return 0; } -static int ptrace_check_debugreg(int _32bit, - unsigned long dr0, unsigned long dr1, - unsigned long dr2, unsigned long dr3, - unsigned long dr6, unsigned long dr7) +int ptrace_check_debugreg(int _32bit, + unsigned long dr0, unsigned long dr1, + unsigned long dr2, unsigned long dr3, + unsigned long dr6, unsigned long dr7) { /* Breakpoint type: 00: --x, 01: -w-, 10: undefined, 11: rw- */ unsigned int rw[4]; diff --git a/arch/x86/mm/Makefile b/arch/x86/mm/Makefile index eefdeee..ddd5abb 100644 --- a/arch/x86/mm/Makefile +++ b/arch/x86/mm/Makefile @@ -21,3 +21,5 @@ obj-$(CONFIG_K8_NUMA) += k8topology_64.o obj-$(CONFIG_ACPI_NUMA) += srat_$(BITS).o obj-$(CONFIG_MEMTEST) += memtest.o + +obj-$(CONFIG_CHECKPOINT) += checkpoint.o diff --git a/arch/x86/mm/checkpoint.c b/arch/x86/mm/checkpoint.c new file mode 100644 index 0000000..f085e14 --- /dev/null +++ b/arch/x86/mm/checkpoint.c @@ -0,0 +1,534 @@ +/* + * Checkpoint/restart - architecture specific support for x86 + * + * Copyright (C) 2008-2009 Oren Laadan + * + * 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. + */ + +/* default debug level for output */ +#define CKPT_DFLAG CKPT_DSYS + +#include +#include + +#include +#include + +/* + * helpers to encode/decode/validate registers/segments/eflags + */ + +static int check_eflags(__u32 eflags) +{ +#define X86_EFLAGS_CKPT_MASK \ + (X86_EFLAGS_CF | X86_EFLAGS_PF | X86_EFLAGS_AF | X86_EFLAGS_ZF | \ + X86_EFLAGS_SF | X86_EFLAGS_TF | X86_EFLAGS_DF | X86_EFLAGS_OF | \ + X86_EFLAGS_NT | X86_EFLAGS_AC | X86_EFLAGS_ID) + + if ((eflags & ~X86_EFLAGS_CKPT_MASK) != (X86_EFLAGS_IF | 0x2)) + return 0; + return 1; +} + +static int check_tls(struct desc_struct *desc) +{ + if (!desc->a && !desc->b) + return 1; + if (desc->l != 0 || desc->s != 1 || desc->dpl != 3) + return 0; + return 1; +} + +static int check_segment(__u16 seg) +{ + int ret = 0; + + switch (seg) { + case CKPT_X86_SEG_NULL: + case CKPT_X86_SEG_USER32_CS: + case CKPT_X86_SEG_USER32_DS: + return 1; + } + if (seg & CKPT_X86_SEG_TLS) { + seg &= ~CKPT_X86_SEG_TLS; + if (seg <= GDT_ENTRY_TLS_MAX - GDT_ENTRY_TLS_MIN) + ret = 1; + } else if (seg & CKPT_X86_SEG_LDT) { + seg &= ~CKPT_X86_SEG_LDT; + if (seg <= 0x1fff) + ret = 1; + } + return ret; +} + +static __u16 encode_segment(unsigned short seg) +{ + if (seg == 0) + return CKPT_X86_SEG_NULL; + BUG_ON((seg & 3) != 3); + + if (seg == __USER_CS) + return CKPT_X86_SEG_USER32_CS; + if (seg == __USER_DS) + return CKPT_X86_SEG_USER32_DS; + + if (seg & 4) + return CKPT_X86_SEG_LDT | (seg >> 3); + + seg >>= 3; + if (GDT_ENTRY_TLS_MIN <= seg && seg <= GDT_ENTRY_TLS_MAX) + return CKPT_X86_SEG_TLS | (seg - GDT_ENTRY_TLS_MIN); + + printk(KERN_ERR "c/r: (decode) bad segment %#hx\n", seg); + BUG(); +} + +static unsigned short decode_segment(__u16 seg) +{ + if (seg == CKPT_X86_SEG_NULL) + return 0; + if (seg == CKPT_X86_SEG_USER32_CS) + return __USER_CS; + if (seg == CKPT_X86_SEG_USER32_DS) + return __USER_DS; + + if (seg & CKPT_X86_SEG_TLS) { + seg &= ~CKPT_X86_SEG_TLS; + return ((GDT_ENTRY_TLS_MIN + seg) << 3) | 3; + } + if (seg & CKPT_X86_SEG_LDT) { + seg &= ~CKPT_X86_SEG_LDT; + return (seg << 3) | 7; + } + BUG(); +} + +#define CKPT_X86_TIF_UNSUPPORTED (_TIF_SECCOMP | _TIF_IO_BITMAP) + +/************************************************************************** + * Checkpoint + */ + +static int may_checkpoint_thread(struct ckpt_ctx *ctx, struct task_struct *t) +{ + if (t->thread.vm86_info) { + ckpt_write_err(ctx, "task %d (%s) in VM86 mode", + task_pid_vnr(t), t->comm); + return -EBUSY; + } + if (task_thread_info(t)->flags & CKPT_X86_TIF_UNSUPPORTED) { + ckpt_write_err(ctx, "task %d (%s) uncool thread flags %#lx", + task_pid_vnr(t), t->comm, + task_thread_info(t)->flags); + return -EBUSY; + } + return 0; +} + +/* dump the thread_struct of a given task */ +int checkpoint_thread(struct ckpt_ctx *ctx, struct task_struct *t) +{ + struct ckpt_hdr_thread *h; + int tls_size; + int ret; + + ret = may_checkpoint_thread(ctx, t); + if (ret < 0) + return ret; + + tls_size = sizeof(t->thread.tls_array); + + h = ckpt_hdr_get_type(ctx, sizeof(*h) + tls_size, CKPT_HDR_THREAD); + if (!h) + return -ENOMEM; + + h->thread_info_flags = + task_thread_info(t)->flags & ~CKPT_X86_TIF_UNSUPPORTED; + h->gdt_entry_tls_entries = GDT_ENTRY_TLS_ENTRIES; + h->sizeof_tls_array = tls_size; + + /* For simplicity dump the entire array */ + memcpy(h + 1, t->thread.tls_array, tls_size); + + ret = ckpt_write_obj(ctx, &h->h); + ckpt_hdr_put(ctx, h); + return ret; +} + +#ifdef CONFIG_X86_32 + +static void save_cpu_regs(struct ckpt_hdr_cpu *h, struct task_struct *t) +{ + struct thread_struct *thread = &t->thread; + struct pt_regs *regs = task_pt_regs(t); + unsigned long _gs; + + h->bp = regs->bp; + h->bx = regs->bx; + h->ax = regs->ax; + h->cx = regs->cx; + h->dx = regs->dx; + h->si = regs->si; + h->di = regs->di; + h->orig_ax = regs->orig_ax; + h->ip = regs->ip; + + h->flags = regs->flags; + h->sp = regs->sp; + + h->cs = encode_segment(regs->cs); + h->ss = encode_segment(regs->ss); + h->ds = encode_segment(regs->ds); + h->es = encode_segment(regs->es); + + /* + * for checkpoint in process context (from within a container) + * the GS segment register should be saved from the hardware; + * otherwise it is already saved on the thread structure + */ + if (t == current) + _gs = get_user_gs(regs); + else + _gs = thread->gs; + + h->fsindex = encode_segment(regs->fs); + h->gsindex = encode_segment(_gs); + + /* + * 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 (t == current) { + BUG_ON(h->orig_ax < 0); + h->ax = 0; + } +} + +static void save_cpu_debug(struct ckpt_hdr_cpu *h, struct task_struct *t) +{ + struct thread_struct *thread = &t->thread; + + /* debug regs */ + + /* + * for checkpoint in process context (from within a container), + * get the actual registers; otherwise get the saved values. + */ + + if (t == current) { + get_debugreg(h->debugreg0, 0); + get_debugreg(h->debugreg1, 1); + get_debugreg(h->debugreg2, 2); + get_debugreg(h->debugreg3, 3); + get_debugreg(h->debugreg6, 6); + get_debugreg(h->debugreg7, 7); + } else { + h->debugreg0 = thread->debugreg0; + h->debugreg1 = thread->debugreg1; + h->debugreg2 = thread->debugreg2; + h->debugreg3 = thread->debugreg3; + h->debugreg6 = thread->debugreg6; + h->debugreg7 = thread->debugreg7; + } +} + +static void save_cpu_fpu(struct ckpt_hdr_cpu *h, struct task_struct *t) +{ + h->used_math = tsk_used_math(t) ? 1 : 0; +} + +static int checkpoint_cpu_fpu(struct ckpt_ctx *ctx, struct task_struct *t) +{ + struct ckpt_hdr *h; + int ret; + + h = ckpt_hdr_get_type(ctx, xstate_size + sizeof(*h), + CKPT_HDR_CPU_FPU); + if (!h) + return -ENOMEM; + + /* i387 + MMU + SSE logic */ + preempt_disable(); /* needed it (t == current) */ + + /* + * normally, no need to unlazy_fpu(), since TS_USEDFPU flag + * was cleared when task was context-switched out... + * except if we are in process context, in which case we do + */ + if (t == current && (task_thread_info(t)->status & TS_USEDFPU)) + unlazy_fpu(current); + + /* + * For simplicity dump the entire structure. + * FIX: need to be deliberate about what registers we are + * dumping for traceability and compatibility. + */ + memcpy(h + 1, t->thread.xstate, xstate_size); + preempt_enable(); /* needed if (t == current) */ + + ret = ckpt_write_obj(ctx, h); + ckpt_hdr_put(ctx, h); + + return ret; +} + +#endif /* CONFIG_X86_32 */ + +/* 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; + + save_cpu_regs(h, t); + save_cpu_debug(h, t); + save_cpu_fpu(h, t); + + ckpt_debug("math %d debug %d\n", h->used_math, !!h->debugreg7); + + ret = ckpt_write_obj(ctx, &h->h); + if (ret < 0) + goto out; + + if (h->used_math) + ret = checkpoint_cpu_fpu(ctx, t); + out: + ckpt_hdr_put(ctx, h); + return ret; +} + +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; + + /* FPU capabilities */ + h->has_fxsr = cpu_has_fxsr; + h->has_xsave = cpu_has_xsave; + h->xstate_size = xstate_size; + + ret = ckpt_write_obj(ctx, &h->h); + ckpt_hdr_put(ctx, h); + + return ret; +} + +/************************************************************************** + * Restart + */ + +/* read the thread_struct into the current task */ +int restore_thread(struct ckpt_ctx *ctx) +{ + struct ckpt_hdr_thread *h; + struct thread_struct *thread = ¤t->thread; + struct desc_struct *desc; + int tls_size; + int i, cpu, ret; + + tls_size = sizeof(thread->tls_array); + + h = ckpt_read_obj_type(ctx, sizeof(*h) + tls_size, CKPT_HDR_THREAD); + if (IS_ERR(h)) + return PTR_ERR(h); + + ret = -EINVAL; + if (h->thread_info_flags & CKPT_X86_TIF_UNSUPPORTED) + goto out; + if (h->gdt_entry_tls_entries != GDT_ENTRY_TLS_ENTRIES) + goto out; + if (h->sizeof_tls_array != tls_size) + goto out; + + /* + * restore TLS by hand: why convert to struct user_desc if + * sys_set_thread_entry() will convert it back ? + */ + desc = (struct desc_struct *) (h + 1); + + for (i = 0; i < GDT_ENTRY_TLS_ENTRIES; i++) { + if (!check_tls(&desc[i])) + goto out; + } + + cpu = get_cpu(); + memcpy(thread->tls_array, desc, tls_size); + load_TLS(thread, cpu); + put_cpu(); + + /* TODO: restore TIF flags as necessary (e.g. TIF_NOTSC) */ + + ret = 0; + out: + ckpt_hdr_put(ctx, h); + return ret; +} + +#ifdef CONFIG_X86_32 + +static int load_cpu_regs(struct ckpt_hdr_cpu *h, struct task_struct *t) +{ + struct thread_struct *thread = &t->thread; + struct pt_regs *regs = task_pt_regs(t); + + if (!check_eflags(h->flags)) + return -EINVAL; + if (h->cs == CKPT_X86_SEG_NULL) + return -EINVAL; + if (!check_segment(h->cs) || !check_segment(h->ds) || + !check_segment(h->es) || !check_segment(h->ss) || + !check_segment(h->fsindex) || !check_segment(h->gsindex)) + return -EINVAL; + + regs->bp = h->bp; + regs->bx = h->bx; + regs->ax = h->ax; + regs->cx = h->cx; + regs->dx = h->dx; + regs->si = h->si; + regs->di = h->di; + regs->orig_ax = h->orig_ax; + regs->ip = h->ip; + + regs->flags = h->flags; + regs->sp = h->sp; + + regs->ds = decode_segment(h->ds); + regs->es = decode_segment(h->es); + regs->cs = decode_segment(h->cs); + regs->ss = decode_segment(h->ss); + + regs->fs = decode_segment(h->fsindex); + regs->gs = decode_segment(h->gsindex); + + thread->gs = regs->gs; + lazy_load_gs(regs->gs); + + return 0; +} + +static int load_cpu_debug(struct ckpt_hdr_cpu *h, struct task_struct *t) +{ + int ret; + + ret = ptrace_check_debugreg(1, h->debugreg0, h->debugreg1, h->debugreg2, + h->debugreg3, h->debugreg6, h->debugreg7); + if (ret < 0) + return ret; + + set_debugreg(h->debugreg0, 0); + set_debugreg(h->debugreg1, 1); + /* ignore 4, 5 */ + set_debugreg(h->debugreg2, 2); + set_debugreg(h->debugreg3, 3); + set_debugreg(h->debugreg6, 6); + set_debugreg(h->debugreg7, 7); + + if (h->debugreg7) + set_tsk_thread_flag(t, TIF_DEBUG); + else + clear_tsk_thread_flag(t, TIF_DEBUG); + + return 0; +} + +static int load_cpu_fpu(struct ckpt_hdr_cpu *h, struct task_struct *t) +{ + preempt_disable(); + + __clear_fpu(t); /* in case we used FPU in user mode */ + + if (!h->used_math) + clear_used_math(); + + preempt_enable(); + return 0; +} + +static int restore_cpu_fpu(struct ckpt_ctx *ctx, struct task_struct *t) +{ + struct ckpt_hdr *h; + int ret; + + /* init_fpu() eventually also calls set_used_math() */ + ret = init_fpu(current); + if (ret < 0) + return ret; + + h = ckpt_read_obj_type(ctx, xstate_size + sizeof(*h), + CKPT_HDR_CPU_FPU); + if (IS_ERR(h)) + return PTR_ERR(h); + + memcpy(t->thread.xstate, h + 1, xstate_size); + + ckpt_hdr_put(ctx, h); + return ret; +} + +#endif /* CONFIG_X86_32 */ + +/* read the cpu state and registers for the current task */ +int restore_cpu(struct ckpt_ctx *ctx) +{ + struct ckpt_hdr_cpu *h; + struct task_struct *t = current; + int ret; + + h = ckpt_read_obj_type(ctx, sizeof(*h), CKPT_HDR_CPU); + if (IS_ERR(h)) + return PTR_ERR(h); + + ckpt_debug("math %d debug %d\n", h->used_math, !!h->debugreg7); + + ret = load_cpu_regs(h, t); + if (ret < 0) + goto out; + ret = load_cpu_debug(h, t); + if (ret < 0) + goto out; + ret = load_cpu_fpu(h, t); + if (ret < 0) + goto out; + + if (h->used_math) + ret = restore_cpu_fpu(ctx, t); + out: + ckpt_hdr_put(ctx, h); + return ret; +} + +int restore_read_header_arch(struct ckpt_ctx *ctx) +{ + struct ckpt_hdr_header_arch *h; + int ret = 0; + + h = ckpt_read_obj_type(ctx, sizeof(*h), CKPT_HDR_HEADER_ARCH); + if (IS_ERR(h)) + return PTR_ERR(h); + + /* FIX: verify compatibility of architecture features */ + + /* verify FPU capabilities */ + if (h->has_fxsr != cpu_has_fxsr || + h->has_xsave != cpu_has_xsave || + h->xstate_size != xstate_size) + ret = -EINVAL; + + ckpt_hdr_put(ctx, h); + return ret; +} diff --git a/checkpoint/checkpoint.c b/checkpoint/checkpoint.c index 7563a9f..a465fb6 100644 --- a/checkpoint/checkpoint.c +++ b/checkpoint/checkpoint.c @@ -203,6 +203,8 @@ static int checkpoint_write_header(struct ckpt_ctx *ctx) do_gettimeofday(&ktv); uts = utsname(); + h->arch_id = cpu_to_le16(CKPT_ARCH_ID); /* see asm/checkpoitn.h */ + h->magic = CHECKPOINT_MAGIC_HEAD; h->major = (LINUX_VERSION_CODE >> 16) & 0xff; h->minor = (LINUX_VERSION_CODE >> 8) & 0xff; @@ -230,7 +232,10 @@ static int checkpoint_write_header(struct ckpt_ctx *ctx) ret = ckpt_write_buffer(ctx, uts->machine, sizeof(uts->machine)); up: up_read(&uts_sem); - return ret; + if (ret < 0) + return ret; + + return checkpoint_write_header_arch(ctx); } /* write the checkpoint trailer */ diff --git a/checkpoint/process.c b/checkpoint/process.c index 9e1b861..d2c59d2 100644 --- a/checkpoint/process.c +++ b/checkpoint/process.c @@ -54,7 +54,15 @@ int checkpoint_task(struct ckpt_ctx *ctx, struct task_struct *t) ret = checkpoint_task_struct(ctx, t); ckpt_debug("task %d\n", ret); - + if (ret < 0) + goto out; + ret = checkpoint_thread(ctx, t); + ckpt_debug("thread %d\n", ret); + if (ret < 0) + goto out; + ret = checkpoint_cpu(ctx, t); + ckpt_debug("cpu %d\n", ret); + out: return ret; } @@ -94,6 +102,14 @@ int restore_task(struct ckpt_ctx *ctx) ret = restore_task_struct(ctx); ckpt_debug("task %d\n", ret); - + if (ret < 0) + goto out; + ret = restore_thread(ctx); + ckpt_debug("thread %d\n", ret); + if (ret < 0) + goto out; + ret = restore_cpu(ctx); + ckpt_debug("cpu %d\n", ret); + out: return ret; } diff --git a/checkpoint/restart.c b/checkpoint/restart.c index 562ce8f..17135fe 100644 --- a/checkpoint/restart.c +++ b/checkpoint/restart.c @@ -265,6 +265,8 @@ static int restore_read_header(struct ckpt_ctx *ctx) return PTR_ERR(h); ret = -EINVAL; + if (le16_to_cpu(h->arch_id) != CKPT_ARCH_ID) + goto out; if (h->magic != CHECKPOINT_MAGIC_HEAD || h->rev != CHECKPOINT_VERSION || h->major != ((LINUX_VERSION_CODE >> 16) & 0xff) || @@ -293,6 +295,10 @@ static int restore_read_header(struct ckpt_ctx *ctx) if (ret < 0) goto out; ret = _ckpt_read_buffer(ctx, uts->machine, sizeof(uts->machine)); + if (ret < 0) + goto out; + + ret = restore_read_header_arch(ctx); out: kfree(uts); ckpt_hdr_put(ctx, h); diff --git a/include/linux/checkpoint.h b/include/linux/checkpoint.h index b2cb91f..f7e2cb8 100644 --- a/include/linux/checkpoint.h +++ b/include/linux/checkpoint.h @@ -57,6 +57,15 @@ extern long do_restart(struct ckpt_ctx *ctx, pid_t pid); extern int checkpoint_task(struct ckpt_ctx *ctx, struct task_struct *t); extern int restore_task(struct ckpt_ctx *ctx); +/* arch hooks */ +extern int checkpoint_write_header_arch(struct ckpt_ctx *ctx); +extern int checkpoint_thread(struct ckpt_ctx *ctx, struct task_struct *t); +extern int checkpoint_cpu(struct ckpt_ctx *ctx, struct task_struct *t); + +extern int restore_read_header_arch(struct ckpt_ctx *ctx); +extern int restore_thread(struct ckpt_ctx *ctx); +extern int restore_cpu(struct ckpt_ctx *ctx); + /* debugging flags */ #define CKPT_DBASE 0x1 /* anything */ diff --git a/include/linux/checkpoint_hdr.h b/include/linux/checkpoint_hdr.h index 827a6bb..ce43aa9 100644 --- a/include/linux/checkpoint_hdr.h +++ b/include/linux/checkpoint_hdr.h @@ -38,19 +38,33 @@ struct ckpt_hdr { __u32 len; } __attribute__((aligned(8))); + +#include + + /* header types */ enum { CKPT_HDR_HEADER = 1, + CKPT_HDR_HEADER_ARCH, CKPT_HDR_BUFFER, CKPT_HDR_STRING, CKPT_HDR_TASK = 101, + CKPT_HDR_THREAD, + CKPT_HDR_CPU, + + /* 201-299: reserved for arch-dependent */ CKPT_HDR_TAIL = 9001, CKPT_HDR_ERROR = 9999, }; +/* architecture */ +enum { + CKPT_ARCH_X86_32 = 1, +}; + /* kernel constants */ struct ckpt_hdr_const { /* task */ @@ -66,7 +80,7 @@ struct ckpt_hdr_header { struct ckpt_hdr h; __u64 magic; - __u16 _padding; + __u16 arch_id; __u16 major; __u16 minor; -- 1.6.0.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/