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kernel-ark/arch/x86_64/ia32/ptrace32.c
Daniel Jacobowitz e8ed11b9dc [PATCH] x86_64: fix 32-bit thread debugging 
The IA32 ptrace emulation currently returns the wrong registers for fs/gs;
it's returning what x86_64 calls gs_base.  We need regs.gsindex in order
for GDB to correctly locate the TLS area.  Without this patch, the 32-bit
GDB testsuite bombs on a 64-bit kernel.  With it, results look about like
I'd expect, although there are still a handful of kernel-related failures
(vsyscall related?).

Signed-off-by: Daniel Jacobowitz <dan@codesourcery.com>
Acked-by: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-08-04 16:28:27 -07:00

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/*
* 32bit ptrace for x86-64.
*
* Copyright 2001,2002 Andi Kleen, SuSE Labs.
* Some parts copied from arch/i386/kernel/ptrace.c. See that file for earlier
* copyright.
*
* This allows to access 64bit processes too; but there is no way to see the extended
* register contents.
*
* $Id: ptrace32.c,v 1.16 2003/03/14 16:06:35 ak Exp $
*/
#include <linux/kernel.h>
#include <linux/stddef.h>
#include <linux/sched.h>
#include <linux/syscalls.h>
#include <linux/unistd.h>
#include <linux/mm.h>
#include <linux/ptrace.h>
#include <asm/ptrace.h>
#include <asm/compat.h>
#include <asm/uaccess.h>
#include <asm/user32.h>
#include <asm/user.h>
#include <asm/errno.h>
#include <asm/debugreg.h>
#include <asm/i387.h>
#include <asm/fpu32.h>
/* determines which flags the user has access to. */
/* 1 = access 0 = no access */
#define FLAG_MASK 0x44dd5UL
#define R32(l,q) \
case offsetof(struct user32, regs.l): stack[offsetof(struct pt_regs, q)/8] = val; break
static int putreg32(struct task_struct *child, unsigned regno, u32 val)
{
int i;
__u64 *stack = (__u64 *)(child->thread.rsp0 - sizeof(struct pt_regs));
switch (regno) {
case offsetof(struct user32, regs.fs):
if (val && (val & 3) != 3) return -EIO;
child->thread.fsindex = val & 0xffff;
break;
case offsetof(struct user32, regs.gs):
if (val && (val & 3) != 3) return -EIO;
child->thread.gsindex = val & 0xffff;
break;
case offsetof(struct user32, regs.ds):
if (val && (val & 3) != 3) return -EIO;
child->thread.ds = val & 0xffff;
break;
case offsetof(struct user32, regs.es):
child->thread.es = val & 0xffff;
break;
case offsetof(struct user32, regs.ss):
if ((val & 3) != 3) return -EIO;
stack[offsetof(struct pt_regs, ss)/8] = val & 0xffff;
break;
case offsetof(struct user32, regs.cs):
if ((val & 3) != 3) return -EIO;
stack[offsetof(struct pt_regs, cs)/8] = val & 0xffff;
break;
R32(ebx, rbx);
R32(ecx, rcx);
R32(edx, rdx);
R32(edi, rdi);
R32(esi, rsi);
R32(ebp, rbp);
R32(eax, rax);
R32(orig_eax, orig_rax);
R32(eip, rip);
R32(esp, rsp);
case offsetof(struct user32, regs.eflags): {
__u64 *flags = &stack[offsetof(struct pt_regs, eflags)/8];
val &= FLAG_MASK;
*flags = val | (*flags & ~FLAG_MASK);
break;
}
case offsetof(struct user32, u_debugreg[4]):
case offsetof(struct user32, u_debugreg[5]):
return -EIO;
case offsetof(struct user32, u_debugreg[0]):
child->thread.debugreg0 = val;
break;
case offsetof(struct user32, u_debugreg[1]):
child->thread.debugreg1 = val;
break;
case offsetof(struct user32, u_debugreg[2]):
child->thread.debugreg2 = val;
break;
case offsetof(struct user32, u_debugreg[3]):
child->thread.debugreg3 = val;
break;
case offsetof(struct user32, u_debugreg[6]):
child->thread.debugreg6 = val;
break;
case offsetof(struct user32, u_debugreg[7]):
val &= ~DR_CONTROL_RESERVED;
/* See arch/i386/kernel/ptrace.c for an explanation of
* this awkward check.*/
for(i=0; i<4; i++)
if ((0x5454 >> ((val >> (16 + 4*i)) & 0xf)) & 1)
return -EIO;
child->thread.debugreg7 = val;
break;
default:
if (regno > sizeof(struct user32) || (regno & 3))
return -EIO;
/* Other dummy fields in the virtual user structure are ignored */
break;
}
return 0;
}
#undef R32
#define R32(l,q) \
case offsetof(struct user32, regs.l): *val = stack[offsetof(struct pt_regs, q)/8]; break
static int getreg32(struct task_struct *child, unsigned regno, u32 *val)
{
__u64 *stack = (__u64 *)(child->thread.rsp0 - sizeof(struct pt_regs));
switch (regno) {
case offsetof(struct user32, regs.fs):
*val = child->thread.fsindex;
break;
case offsetof(struct user32, regs.gs):
*val = child->thread.gsindex;
break;
case offsetof(struct user32, regs.ds):
*val = child->thread.ds;
break;
case offsetof(struct user32, regs.es):
*val = child->thread.es;
break;
R32(cs, cs);
R32(ss, ss);
R32(ebx, rbx);
R32(ecx, rcx);
R32(edx, rdx);
R32(edi, rdi);
R32(esi, rsi);
R32(ebp, rbp);
R32(eax, rax);
R32(orig_eax, orig_rax);
R32(eip, rip);
R32(eflags, eflags);
R32(esp, rsp);
case offsetof(struct user32, u_debugreg[0]):
*val = child->thread.debugreg0;
break;
case offsetof(struct user32, u_debugreg[1]):
*val = child->thread.debugreg1;
break;
case offsetof(struct user32, u_debugreg[2]):
*val = child->thread.debugreg2;
break;
case offsetof(struct user32, u_debugreg[3]):
*val = child->thread.debugreg3;
break;
case offsetof(struct user32, u_debugreg[6]):
*val = child->thread.debugreg6;
break;
case offsetof(struct user32, u_debugreg[7]):
*val = child->thread.debugreg7;
break;
default:
if (regno > sizeof(struct user32) || (regno & 3))
return -EIO;
/* Other dummy fields in the virtual user structure are ignored */
*val = 0;
break;
}
return 0;
}
#undef R32
static struct task_struct *find_target(int request, int pid, int *err)
{
struct task_struct *child;
*err = -EPERM;
if (pid == 1)
return NULL;
*err = -ESRCH;
read_lock(&tasklist_lock);
child = find_task_by_pid(pid);
if (child)
get_task_struct(child);
read_unlock(&tasklist_lock);
if (child) {
*err = -EPERM;
if (child->pid == 1)
goto out;
*err = ptrace_check_attach(child, request == PTRACE_KILL);
if (*err < 0)
goto out;
return child;
}
out:
if (child)
put_task_struct(child);
return NULL;
}
asmlinkage long sys32_ptrace(long request, u32 pid, u32 addr, u32 data)
{
struct task_struct *child;
struct pt_regs *childregs;
void __user *datap = compat_ptr(data);
int ret;
__u32 val;
switch (request) {
default:
return sys_ptrace(request, pid, addr, data);
case PTRACE_PEEKTEXT:
case PTRACE_PEEKDATA:
case PTRACE_POKEDATA:
case PTRACE_POKETEXT:
case PTRACE_POKEUSR:
case PTRACE_PEEKUSR:
case PTRACE_GETREGS:
case PTRACE_SETREGS:
case PTRACE_SETFPREGS:
case PTRACE_GETFPREGS:
case PTRACE_SETFPXREGS:
case PTRACE_GETFPXREGS:
case PTRACE_GETEVENTMSG:
break;
}
child = find_target(request, pid, &ret);
if (!child)
return ret;
childregs = (struct pt_regs *)(child->thread.rsp0 - sizeof(struct pt_regs));
switch (request) {
case PTRACE_PEEKDATA:
case PTRACE_PEEKTEXT:
ret = 0;
if (access_process_vm(child, addr, &val, sizeof(u32), 0)!=sizeof(u32))
ret = -EIO;
else
ret = put_user(val, (unsigned int __user *)datap);
break;
case PTRACE_POKEDATA:
case PTRACE_POKETEXT:
ret = 0;
if (access_process_vm(child, addr, &data, sizeof(u32), 1)!=sizeof(u32))
ret = -EIO;
break;
case PTRACE_PEEKUSR:
ret = getreg32(child, addr, &val);
if (ret == 0)
ret = put_user(val, (__u32 __user *)datap);
break;
case PTRACE_POKEUSR:
ret = putreg32(child, addr, data);
break;
case PTRACE_GETREGS: { /* Get all gp regs from the child. */
int i;
if (!access_ok(VERIFY_WRITE, datap, 16*4)) {
ret = -EIO;
break;
}
ret = 0;
for ( i = 0; i <= 16*4 ; i += sizeof(__u32) ) {
getreg32(child, i, &val);
ret |= __put_user(val,(u32 __user *)datap);
datap += sizeof(u32);
}
break;
}
case PTRACE_SETREGS: { /* Set all gp regs in the child. */
unsigned long tmp;
int i;
if (!access_ok(VERIFY_READ, datap, 16*4)) {
ret = -EIO;
break;
}
ret = 0;
for ( i = 0; i <= 16*4; i += sizeof(u32) ) {
ret |= __get_user(tmp, (u32 __user *)datap);
putreg32(child, i, tmp);
datap += sizeof(u32);
}
break;
}
case PTRACE_GETFPREGS:
ret = -EIO;
if (!access_ok(VERIFY_READ, compat_ptr(data),
sizeof(struct user_i387_struct)))
break;
save_i387_ia32(child, datap, childregs, 1);
ret = 0;
break;
case PTRACE_SETFPREGS:
ret = -EIO;
if (!access_ok(VERIFY_WRITE, datap,
sizeof(struct user_i387_struct)))
break;
ret = 0;
/* don't check EFAULT to be bug-to-bug compatible to i386 */
restore_i387_ia32(child, datap, 1);
break;
case PTRACE_GETFPXREGS: {
struct user32_fxsr_struct __user *u = datap;
init_fpu(child);
ret = -EIO;
if (!access_ok(VERIFY_WRITE, u, sizeof(*u)))
break;
ret = -EFAULT;
if (__copy_to_user(u, &child->thread.i387.fxsave, sizeof(*u)))
break;
ret = __put_user(childregs->cs, &u->fcs);
ret |= __put_user(child->thread.ds, &u->fos);
break;
}
case PTRACE_SETFPXREGS: {
struct user32_fxsr_struct __user *u = datap;
unlazy_fpu(child);
ret = -EIO;
if (!access_ok(VERIFY_READ, u, sizeof(*u)))
break;
/* no checking to be bug-to-bug compatible with i386 */
__copy_from_user(&child->thread.i387.fxsave, u, sizeof(*u));
set_stopped_child_used_math(child);
child->thread.i387.fxsave.mxcsr &= mxcsr_feature_mask;
ret = 0;
break;
}
case PTRACE_GETEVENTMSG:
ret = put_user(child->ptrace_message,(unsigned int __user *)compat_ptr(data));
break;
default:
ret = -EINVAL;
break;
}
put_task_struct(child);
return ret;
}
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