Commit d1254b12 authored by Jeff Dike's avatar Jeff Dike Committed by Linus Torvalds
Browse files

uml: fix x86_64 core dump crash 



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: default avatarJeff Dike <jdike@linux.intel.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent c7ec16da

arch/um/os-Linux/sys-x86_64/registers.c

+15 −0
Original line number Diff line number Diff line
@@ -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));

arch/um/sys-x86_64/ptrace.c

+0 −6
Original line number Diff line number Diff line
@@ -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");

include/asm-um/elf-x86_64.h

+40 −0
Original line number Diff line number Diff line
@@ -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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