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linux-next/arch/xtensa/kernel/ptrace.c
Chris Zankel 42086cec32 [XTENSA] Allow debugger to modify the WINDOWBASE register. 
For the 'return' command, GDB needs to adjust WINDOWBASE.
In case WB is different from 0, we need to rotate the
window register file and update WINDOWSTART and WMASK.
This patch also removes some ret|= statements for
__get_user/__put_user as the address range was alrady
checked a couple of lines earlier.

Signed-off-by: Chris Zankel <chris@zankel.net>
2008-02-13 17:45:36 -08:00

378 lines
8.9 KiB
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// TODO some minor issues
/*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
* Copyright (C) 2001 - 2007 Tensilica Inc.
*
* Joe Taylor <joe@tensilica.com, joetylr@yahoo.com>
* Chris Zankel <chris@zankel.net>
* Scott Foehner<sfoehner@yahoo.com>,
* Kevin Chea
* Marc Gauthier<marc@tensilica.com> <marc@alumni.uwaterloo.ca>
*/
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/errno.h>
#include <linux/ptrace.h>
#include <linux/smp.h>
#include <linux/security.h>
#include <linux/signal.h>
#include <asm/pgtable.h>
#include <asm/page.h>
#include <asm/system.h>
#include <asm/uaccess.h>
#include <asm/ptrace.h>
#include <asm/elf.h>
#include <asm/coprocessor.h>
/*
* Called by kernel/ptrace.c when detaching to disable single stepping.
*/
void ptrace_disable(struct task_struct *child)
{
/* Nothing to do.. */
}
int ptrace_getregs(struct task_struct *child, void __user *uregs)
{
struct pt_regs *regs = task_pt_regs(child);
xtensa_gregset_t __user *gregset = uregs;
unsigned long wm = regs->wmask;
unsigned long wb = regs->windowbase;
int live, i;
if (!access_ok(VERIFY_WRITE, uregs, sizeof(xtensa_gregset_t)))
return -EIO;
__put_user(regs->pc, &gregset->pc);
__put_user(regs->ps & ~(1 << PS_EXCM_BIT), &gregset->ps);
__put_user(regs->lbeg, &gregset->lbeg);
__put_user(regs->lend, &gregset->lend);
__put_user(regs->lcount, &gregset->lcount);
__put_user(regs->windowstart, &gregset->windowstart);
__put_user(regs->windowbase, &gregset->windowbase);
live = (wm & 2) ? 4 : (wm & 4) ? 8 : (wm & 8) ? 12 : 16;
for (i = 0; i < live; i++)
__put_user(regs->areg[i],gregset->a+((wb*4+i)%XCHAL_NUM_AREGS));
for (i = XCHAL_NUM_AREGS - (wm >> 4) * 4; i < XCHAL_NUM_AREGS; i++)
__put_user(regs->areg[i],gregset->a+((wb*4+i)%XCHAL_NUM_AREGS));
return 0;
}
int ptrace_setregs(struct task_struct *child, void __user *uregs)
{
struct pt_regs *regs = task_pt_regs(child);
xtensa_gregset_t *gregset = uregs;
const unsigned long ps_mask = PS_CALLINC_MASK | PS_OWB_MASK;
unsigned long ps;
unsigned long wb;
if (!access_ok(VERIFY_WRITE, uregs, sizeof(xtensa_gregset_t)))
return -EIO;
__get_user(regs->pc, &gregset->pc);
__get_user(ps, &gregset->ps);
__get_user(regs->lbeg, &gregset->lbeg);
__get_user(regs->lend, &gregset->lend);
__get_user(regs->lcount, &gregset->lcount);
__get_user(regs->windowstart, &gregset->windowstart);
__get_user(wb, &gregset->windowbase);
regs->ps = (regs->ps & ~ps_mask) | (ps & ps_mask) | (1 << PS_EXCM_BIT);
if (wb >= XCHAL_NUM_AREGS / 4)
return -EFAULT;
regs->windowbase = wb;
if (wb != 0 && __copy_from_user(regs->areg + XCHAL_NUM_AREGS - wb * 4,
gregset->a, wb * 16))
return -EFAULT;
if (__copy_from_user(regs->areg, gregset->a + wb*4, (WSBITS-wb) * 16))
return -EFAULT;
return 0;
}
int ptrace_getxregs(struct task_struct *child, void __user *uregs)
{
struct pt_regs *regs = task_pt_regs(child);
struct thread_info *ti = task_thread_info(child);
elf_xtregs_t __user *xtregs = uregs;
int ret = 0;
if (!access_ok(VERIFY_WRITE, uregs, sizeof(elf_xtregs_t)))
return -EIO;
#if XTENSA_HAVE_COPROCESSORS
/* Flush all coprocessor registers to memory. */
coprocessor_flush_all(ti);
ret |= __copy_to_user(&xtregs->cp0, &ti->xtregs_cp,
sizeof(xtregs_coprocessor_t));
#endif
ret |= __copy_to_user(&xtregs->opt, &regs->xtregs_opt,
sizeof(xtregs->opt));
ret |= __copy_to_user(&xtregs->user,&ti->xtregs_user,
sizeof(xtregs->user));
return ret ? -EFAULT : 0;
}
int ptrace_setxregs(struct task_struct *child, void __user *uregs)
{
struct thread_info *ti = task_thread_info(child);
struct pt_regs *regs = task_pt_regs(child);
elf_xtregs_t *xtregs = uregs;
int ret = 0;
#if XTENSA_HAVE_COPROCESSORS
/* Flush all coprocessors before we overwrite them. */
coprocessor_flush_all(ti);
coprocessor_release_all(ti);
ret |= __copy_from_user(&ti->xtregs_cp, &xtregs->cp0,
sizeof(xtregs_coprocessor_t));
#endif
ret |= __copy_from_user(&regs->xtregs_opt, &xtregs->opt,
sizeof(xtregs->opt));
ret |= __copy_from_user(&ti->xtregs_user, &xtregs->user,
sizeof(xtregs->user));
return ret ? -EFAULT : 0;
}
int ptrace_peekusr(struct task_struct *child, long regno, long __user *ret)
{
struct pt_regs *regs;
unsigned long tmp;
regs = task_pt_regs(child);
tmp = 0; /* Default return value. */
switch(regno) {
case REG_AR_BASE ... REG_AR_BASE + XCHAL_NUM_AREGS - 1:
tmp = regs->areg[regno - REG_AR_BASE];
break;
case REG_A_BASE ... REG_A_BASE + 15:
tmp = regs->areg[regno - REG_A_BASE];
break;
case REG_PC:
tmp = regs->pc;
break;
case REG_PS:
/* Note: PS.EXCM is not set while user task is running;
* its being set in regs is for exception handling
* convenience. */
tmp = (regs->ps & ~(1 << PS_EXCM_BIT));
break;
case REG_WB:
break; /* tmp = 0 */
case REG_WS:
{
unsigned long wb = regs->windowbase;
unsigned long ws = regs->windowstart;
tmp = ((ws>>wb) | (ws<<(WSBITS-wb))) & ((1<<WSBITS)-1);
break;
}
case REG_LBEG:
tmp = regs->lbeg;
break;
case REG_LEND:
tmp = regs->lend;
break;
case REG_LCOUNT:
tmp = regs->lcount;
break;
case REG_SAR:
tmp = regs->sar;
break;
case SYSCALL_NR:
tmp = regs->syscall;
break;
default:
return -EIO;
}
return put_user(tmp, ret);
}
int ptrace_pokeusr(struct task_struct *child, long regno, long val)
{
struct pt_regs *regs;
regs = task_pt_regs(child);
switch (regno) {
case REG_AR_BASE ... REG_AR_BASE + XCHAL_NUM_AREGS - 1:
regs->areg[regno - REG_AR_BASE] = val;
break;
case REG_A_BASE ... REG_A_BASE + 15:
regs->areg[regno - REG_A_BASE] = val;
break;
case REG_PC:
regs->pc = val;
break;
case SYSCALL_NR:
regs->syscall = val;
break;
default:
return -EIO;
}
return 0;
}
long arch_ptrace(struct task_struct *child, long request, long addr, long data)
{
int ret = -EPERM;
switch (request) {
case PTRACE_PEEKTEXT: /* read word at location addr. */
case PTRACE_PEEKDATA:
ret = generic_ptrace_peekdata(child, addr, data);
break;
case PTRACE_PEEKUSR: /* read register specified by addr. */
ret = ptrace_peekusr(child, addr, (void __user *) data);
break;
case PTRACE_POKETEXT: /* write the word at location addr. */
case PTRACE_POKEDATA:
ret = generic_ptrace_pokedata(child, addr, data);
break;
case PTRACE_POKEUSR: /* write register specified by addr. */
ret = ptrace_pokeusr(child, addr, data);
break;
/* continue and stop at next (return from) syscall */
case PTRACE_SYSCALL:
case PTRACE_CONT: /* restart after signal. */
{
ret = -EIO;
if (!valid_signal(data))
break;
if (request == PTRACE_SYSCALL)
set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
else
clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
child->exit_code = data;
/* Make sure the single step bit is not set. */
child->ptrace &= ~PT_SINGLESTEP;
wake_up_process(child);
ret = 0;
break;
}
/*
* make the child exit. Best I can do is send it a sigkill.
* perhaps it should be put in the status that it wants to
* exit.
*/
case PTRACE_KILL:
ret = 0;
if (child->exit_state == EXIT_ZOMBIE) /* already dead */
break;
child->exit_code = SIGKILL;
child->ptrace &= ~PT_SINGLESTEP;
wake_up_process(child);
break;
case PTRACE_SINGLESTEP:
ret = -EIO;
if (!valid_signal(data))
break;
clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
child->ptrace |= PT_SINGLESTEP;
child->exit_code = data;
wake_up_process(child);
ret = 0;
break;
case PTRACE_GETREGS:
ret = ptrace_getregs(child, (void __user *) data);
break;
case PTRACE_SETREGS:
ret = ptrace_setregs(child, (void __user *) data);
break;
case PTRACE_GETXTREGS:
ret = ptrace_getxregs(child, (void __user *) data);
break;
case PTRACE_SETXTREGS:
ret = ptrace_setxregs(child, (void __user *) data);
break;
default:
ret = ptrace_request(child, request, addr, data);
break;
}
return ret;
}
void do_syscall_trace(void)
{
/*
* The 0x80 provides a way for the tracing parent to distinguish
* between a syscall stop and SIGTRAP delivery
*/
ptrace_notify(SIGTRAP|((current->ptrace & PT_TRACESYSGOOD) ? 0x80 : 0));
/*
* this isn't the same as continuing with a signal, but it will do
* for normal use. strace only continues with a signal if the
* stopping signal is not SIGTRAP. -brl
*/
if (current->exit_code) {
send_sig(current->exit_code, current, 1);
current->exit_code = 0;
}
}
void do_syscall_trace_enter(struct pt_regs *regs)
{
if (test_thread_flag(TIF_SYSCALL_TRACE)
&& (current->ptrace & PT_PTRACED))
do_syscall_trace();
#if 0
if (unlikely(current->audit_context))
audit_syscall_entry(current, AUDIT_ARCH_XTENSA..);
#endif
}
void do_syscall_trace_leave(struct pt_regs *regs)
{
if ((test_thread_flag(TIF_SYSCALL_TRACE))
&& (current->ptrace & PT_PTRACED))
do_syscall_trace();
}
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