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Commit 6e6d74cf authored by Jeff Dike's avatar Jeff Dike Committed by Linus Torvalds
Browse files

[PATCH] uml: x86_64 ptrace fixes 



This patch fixes some missing ptrace bits on x86_64.  PTRACE_ARCH_PRCTL is
hooked up and implemented.  This required generalizing arch_prctl_skas
slightly to take a task_struct to modify.  Previously, it always operated on
current.

Reading and writing the debug registers is also enabled by un-ifdefing the
code that implements that.  It turns out that x86_64 is identical to i386, so
the same code can be used.

Signed-off-by: default avatarJeff Dike <jdike@addtoit.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent f355559c

arch/um/kernel/ptrace.c

+7 −0
Original line number Diff line number Diff line
@@ -18,6 +18,7 @@ 
#include "kern_util.h"

#include "skas_ptrace.h"

#include "sysdep/ptrace.h"

#include "os.h"



static inline void set_singlestepping(struct task_struct *child, int on)

{
@@ -240,6 +241,12 @@ long arch_ptrace(struct task_struct *child, long request, long addr, long data) 
		ret = 0;

		break;

	}

#endif

#ifdef PTRACE_ARCH_PRCTL

        case PTRACE_ARCH_PRCTL:

                /* XXX Calls ptrace on the host - needs some SMP thinking */

                ret = arch_prctl_skas(child, data, (void *) addr);

                break;

#endif

	default:

		ret = ptrace_request(child, request, addr, data);

arch/um/sys-x86_64/ptrace.c

+0 −5
Original line number Diff line number Diff line
@@ -71,8 +71,6 @@ int poke_user(struct task_struct *child, long addr, long data) 


        if (addr < MAX_REG_OFFSET)

                return putreg(child, addr, data);



#if 0 /* Need x86_64 debugregs handling */

        else if((addr >= offsetof(struct user, u_debugreg[0])) &&

                (addr <= offsetof(struct user, u_debugreg[7]))){

                addr -= offsetof(struct user, u_debugreg[0]);
@@ -81,7 +79,6 @@ int poke_user(struct task_struct *child, long addr, long data) 
                child->thread.arch.debugregs[addr] = data;

                return 0;

        }

#endif

        return -EIO;

}
@@ -119,14 +116,12 @@ int peek_user(struct task_struct *child, long addr, long data) 
        if(addr < MAX_REG_OFFSET){

                tmp = getreg(child, addr);

        }

#if 0 /* Need x86_64 debugregs handling */

        else if((addr >= offsetof(struct user, u_debugreg[0])) &&

                (addr <= offsetof(struct user, u_debugreg[7]))){

                addr -= offsetof(struct user, u_debugreg[0]);

                addr = addr >> 2;

                tmp = child->thread.arch.debugregs[addr];

        }

#endif

        return put_user(tmp, (unsigned long *) data);

}

arch/um/sys-x86_64/syscalls.c

+8 −6
Original line number Diff line number Diff line
@@ -59,18 +59,20 @@ static long arch_prctl_tt(int code, unsigned long addr) 


#ifdef CONFIG_MODE_SKAS



static long arch_prctl_skas(int code, unsigned long __user *addr)

long arch_prctl_skas(struct task_struct *task, int code,

                     unsigned long __user *addr)

{

        unsigned long *ptr = addr, tmp;

	long ret;

        int pid = current->mm->context.skas.id.u.pid;

	int pid = task->mm->context.skas.id.u.pid;



	/*

	 * With ARCH_SET_FS (and ARCH_SET_GS is treated similarly to

	 * be safe), we need to call arch_prctl on the host because

	 * setting %fs may result in something else happening (like a

	 * GDT being set instead).  So, we let the host fiddle the

	 * registers and restore them afterwards.

	 * GDT or thread.fs being set instead).  So, we let the host

	 * fiddle the registers and thread struct and restore the

	 * registers afterwards.

	 *

	 * So, the saved registers are stored to the process (this

	 * needed because a stub may have been the last thing to run),
@@ -118,7 +120,7 @@ static long arch_prctl_skas(int code, unsigned long __user *addr) 


long sys_arch_prctl(int code, unsigned long addr)

{

	return CHOOSE_MODE_PROC(arch_prctl_tt, arch_prctl_skas, code,

	return CHOOSE_MODE_PROC(arch_prctl_tt, arch_prctl_skas, current, code,

                                (unsigned long __user *) addr);

}
@@ -141,6 +143,6 @@ void arch_switch_to_skas(struct task_struct *from, struct task_struct *to) 
        if(to->thread.arch.fs == 0)

                return;



        arch_prctl_skas(ARCH_SET_FS, (void __user *) to->thread.arch.fs);

        arch_prctl_skas(to, ARCH_SET_FS, (void __user *) to->thread.arch.fs);

}

include/asm-um/ptrace-x86_64.h

+3 −0
Original line number Diff line number Diff line
@@ -84,4 +84,7 @@ static inline void arch_switch_to_tt(struct task_struct *from, 
extern void arch_switch_to_skas(struct task_struct *from,

				struct task_struct *to);



extern long arch_prctl_skas(struct task_struct *task, int code,

			    unsigned long __user *addr);



#endif