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Message-Id: <20070822144921.d057c654.akpm@linux-foundation.org>
Date: Wed, 22 Aug 2007 14:49:21 -0700
From: Andrew Morton <akpm@...ux-foundation.org>
To: Jeff Dike <jdike@...toit.com>
Cc: LKML <linux-kernel@...r.kernel.org>,
uml-devel <user-mode-linux-devel@...ts.sourceforge.net>,
vberk@...s.dartmouth.edu,
Alberto Pires de Oliveira Neto <apon1@...ra.com.br>
Subject: Re: [PATCH 2/2] UML - Fix x86_64 core dump crash
On Wed, 22 Aug 2007 17:25:30 -0400
Jeff Dike <jdike@...toit.com> wrote:
> --- linux-2.6.22.orig/arch/um/os-Linux/sys-x86_64/registers.c 2007-08-22 16:55:38.000000000 -0400
> +++ linux-2.6.22/arch/um/os-Linux/sys-x86_64/registers.c 2007-08-22 16:56:20.000000000 -0400
> @@ -3,11 +3,27 @@
> * Licensed under the GPL
> */
>
> +#include <errno.h>
> +#include <sys/ptrace.h>
> #define __FRAME_OFFSETS
> #include <asm/ptrace.h>
> #include "longjmp.h"
> #include "user.h"
>
> +int save_fp_registers(int pid, unsigned long *fp_regs)
> +{
> + if(ptrace(PTRACE_GETFPREGS, pid, 0, fp_regs) < 0)
> + return -errno;
> + return 0;
> +}
> +
> +int restore_fp_registers(int pid, unsigned long *fp_regs)
> +{
> + if(ptrace(PTRACE_SETFPREGS, pid, 0, fp_regs) < 0)
> + return -errno;
> + return 0;
> +}
> +
> unsigned long get_thread_reg(int reg, jmp_buf *buf)
This doesn't apply to current mainline in ways which I'm not entirely
comfortable fixing. (it assumes the presence of queued-for-2.6.24 things).
Does the below still work?
From: Jeff Dike <jdike@...toit.com>
Stop UML crashing when trying to dump a process core on x86_64. This is the
minimal fix to stop the crash - more things are broken here, and patches are
forthcoming.
The immediate thing to do is define ELF_CORE_COPY_REGS and
ELF_CORE_COPY_FPREGS. Defining ELF_CORE_COPY_FPREGS allows dump_fpu to go
away. It is defined in terms of save_fp_registers, so that needs to be added.
Signed-off-by: Jeff Dike <jdike@...ux.intel.com>
Signed-off-by: Andrew Morton <akpm@...ux-foundation.org>
---
arch/um/os-Linux/sys-x86_64/registers.c | 15 ++++++++
arch/um/sys-x86_64/ptrace.c | 6 ---
include/asm-um/elf-x86_64.h | 40 ++++++++++++++++++++++
3 files changed, 55 insertions(+), 6 deletions(-)
diff -puN arch/um/os-Linux/sys-x86_64/registers.c~uml-fix-x86_64-core-dump-crash arch/um/os-Linux/sys-x86_64/registers.c
--- a/arch/um/os-Linux/sys-x86_64/registers.c~uml-fix-x86_64-core-dump-crash
+++ a/arch/um/os-Linux/sys-x86_64/registers.c
@@ -4,6 +4,7 @@
*/
#include <errno.h>
+#include <sys/ptrace.h>
#include <string.h>
#include "ptrace_user.h"
#include "uml-config.h"
@@ -17,6 +18,20 @@
static unsigned long exec_regs[MAX_REG_NR];
static unsigned long exec_fp_regs[HOST_FP_SIZE];
+int save_fp_registers(int pid, unsigned long *fp_regs)
+{
+ if(ptrace(PTRACE_GETFPREGS, pid, 0, fp_regs) < 0)
+ return -errno;
+ return 0;
+}
+
+int restore_fp_registers(int pid, unsigned long *fp_regs)
+{
+ if(ptrace(PTRACE_SETFPREGS, pid, 0, fp_regs) < 0)
+ return -errno;
+ return 0;
+}
+
void init_thread_registers(union uml_pt_regs *to)
{
memcpy(to->skas.regs, exec_regs, sizeof(to->skas.regs));
diff -puN arch/um/sys-x86_64/ptrace.c~uml-fix-x86_64-core-dump-crash arch/um/sys-x86_64/ptrace.c
--- a/arch/um/sys-x86_64/ptrace.c~uml-fix-x86_64-core-dump-crash
+++ a/arch/um/sys-x86_64/ptrace.c
@@ -156,12 +156,6 @@ int is_syscall(unsigned long addr)
return(instr == 0x050f);
}
-int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu )
-{
- panic("dump_fpu");
- return(1);
-}
-
int get_fpregs(unsigned long buf, struct task_struct *child)
{
panic("get_fpregs");
diff -puN include/asm-um/elf-x86_64.h~uml-fix-x86_64-core-dump-crash include/asm-um/elf-x86_64.h
--- a/include/asm-um/elf-x86_64.h~uml-fix-x86_64-core-dump-crash
+++ a/include/asm-um/elf-x86_64.h
@@ -6,7 +6,9 @@
#ifndef __UM_ELF_X86_64_H
#define __UM_ELF_X86_64_H
+#include <linux/sched.h>
#include <asm/user.h>
+#include "skas.h"
/* x86-64 relocation types, taken from asm-x86_64/elf.h */
#define R_X86_64_NONE 0 /* No reloc */
@@ -64,6 +66,44 @@ typedef struct { } elf_fpregset_t;
PT_REGS_R15(regs) = 0; \
} while (0)
+#define ELF_CORE_COPY_REGS(pr_reg, regs) \
+ (pr_reg)[0] = (regs)->regs.gp[0]; \
+ (pr_reg)[1] = (regs)->regs.gp[1]; \
+ (pr_reg)[2] = (regs)->regs.gp[2]; \
+ (pr_reg)[3] = (regs)->regs.gp[3]; \
+ (pr_reg)[4] = (regs)->regs.gp[4]; \
+ (pr_reg)[5] = (regs)->regs.gp[5]; \
+ (pr_reg)[6] = (regs)->regs.gp[6]; \
+ (pr_reg)[7] = (regs)->regs.gp[7]; \
+ (pr_reg)[8] = (regs)->regs.gp[8]; \
+ (pr_reg)[9] = (regs)->regs.gp[9]; \
+ (pr_reg)[10] = (regs)->regs.gp[10]; \
+ (pr_reg)[11] = (regs)->regs.gp[11]; \
+ (pr_reg)[12] = (regs)->regs.gp[12]; \
+ (pr_reg)[13] = (regs)->regs.gp[13]; \
+ (pr_reg)[14] = (regs)->regs.gp[14]; \
+ (pr_reg)[15] = (regs)->regs.gp[15]; \
+ (pr_reg)[16] = (regs)->regs.gp[16]; \
+ (pr_reg)[17] = (regs)->regs.gp[17]; \
+ (pr_reg)[18] = (regs)->regs.gp[18]; \
+ (pr_reg)[19] = (regs)->regs.gp[19]; \
+ (pr_reg)[20] = (regs)->regs.gp[20]; \
+ (pr_reg)[21] = current->thread.arch.fs; \
+ (pr_reg)[22] = 0; \
+ (pr_reg)[23] = 0; \
+ (pr_reg)[24] = 0; \
+ (pr_reg)[25] = 0; \
+ (pr_reg)[26] = 0;
+
+static inline int elf_core_copy_fpregs(struct task_struct *t,
+ elf_fpregset_t *fpu)
+{
+ int cpu = current_thread->cpu;
+ return save_fp_registers(userspace_pid[cpu], (unsigned long *) fpu);
+}
+
+#define ELF_CORE_COPY_FPREGS(t, fpu) elf_core_copy_fpregs(t, fpu)
+
#ifdef TIF_IA32 /* XXX */
#error XXX, indeed
clear_thread_flag(TIF_IA32);
_
-
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