mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-09-12 13:55:32 +00:00
![Roland McGrath](/assets/img/avatar_default.png)
This cleans up the getreg/putreg functions to move the special cases (segment registers and eflags) out into their own subroutines. Signed-off-by: Roland McGrath <roland@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
519 lines
13 KiB
C
519 lines
13 KiB
C
/* By Ross Biro 1/23/92 */
|
|
/*
|
|
* Pentium III FXSR, SSE support
|
|
* Gareth Hughes <gareth@valinux.com>, May 2000
|
|
*/
|
|
|
|
#include <linux/kernel.h>
|
|
#include <linux/sched.h>
|
|
#include <linux/mm.h>
|
|
#include <linux/smp.h>
|
|
#include <linux/errno.h>
|
|
#include <linux/ptrace.h>
|
|
#include <linux/user.h>
|
|
#include <linux/security.h>
|
|
#include <linux/audit.h>
|
|
#include <linux/seccomp.h>
|
|
#include <linux/signal.h>
|
|
|
|
#include <asm/uaccess.h>
|
|
#include <asm/pgtable.h>
|
|
#include <asm/system.h>
|
|
#include <asm/processor.h>
|
|
#include <asm/i387.h>
|
|
#include <asm/debugreg.h>
|
|
#include <asm/ldt.h>
|
|
#include <asm/desc.h>
|
|
|
|
/*
|
|
* does not yet catch signals sent when the child dies.
|
|
* in exit.c or in signal.c.
|
|
*/
|
|
|
|
/*
|
|
* Determines which flags the user has access to [1 = access, 0 = no access].
|
|
*/
|
|
#define FLAG_MASK_32 ((unsigned long) \
|
|
(X86_EFLAGS_CF | X86_EFLAGS_PF | \
|
|
X86_EFLAGS_AF | X86_EFLAGS_ZF | \
|
|
X86_EFLAGS_SF | X86_EFLAGS_TF | \
|
|
X86_EFLAGS_DF | X86_EFLAGS_OF | \
|
|
X86_EFLAGS_RF | X86_EFLAGS_AC))
|
|
|
|
#define FLAG_MASK FLAG_MASK_32
|
|
|
|
static long *pt_regs_access(struct pt_regs *regs, unsigned long regno)
|
|
{
|
|
BUILD_BUG_ON(offsetof(struct pt_regs, bx) != 0);
|
|
regno >>= 2;
|
|
if (regno > FS)
|
|
--regno;
|
|
return ®s->bx + regno;
|
|
}
|
|
|
|
static u16 get_segment_reg(struct task_struct *task, unsigned long offset)
|
|
{
|
|
/*
|
|
* Returning the value truncates it to 16 bits.
|
|
*/
|
|
unsigned int retval;
|
|
if (offset != offsetof(struct user_regs_struct, gs))
|
|
retval = *pt_regs_access(task_pt_regs(task), offset);
|
|
else {
|
|
retval = task->thread.gs;
|
|
if (task == current)
|
|
savesegment(gs, retval);
|
|
}
|
|
return retval;
|
|
}
|
|
|
|
static int set_segment_reg(struct task_struct *task,
|
|
unsigned long offset, u16 value)
|
|
{
|
|
/*
|
|
* The value argument was already truncated to 16 bits.
|
|
*/
|
|
if (value && (value & 3) != 3)
|
|
return -EIO;
|
|
|
|
if (offset != offsetof(struct user_regs_struct, gs))
|
|
*pt_regs_access(task_pt_regs(task), offset) = value;
|
|
else {
|
|
task->thread.gs = value;
|
|
if (task == current)
|
|
/*
|
|
* The user-mode %gs is not affected by
|
|
* kernel entry, so we must update the CPU.
|
|
*/
|
|
loadsegment(gs, value);
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static unsigned long get_flags(struct task_struct *task)
|
|
{
|
|
unsigned long retval = task_pt_regs(task)->flags;
|
|
|
|
/*
|
|
* If the debugger set TF, hide it from the readout.
|
|
*/
|
|
if (test_tsk_thread_flag(task, TIF_FORCED_TF))
|
|
retval &= ~X86_EFLAGS_TF;
|
|
|
|
return retval;
|
|
}
|
|
|
|
static int set_flags(struct task_struct *task, unsigned long value)
|
|
{
|
|
struct pt_regs *regs = task_pt_regs(task);
|
|
|
|
/*
|
|
* If the user value contains TF, mark that
|
|
* it was not "us" (the debugger) that set it.
|
|
* If not, make sure it stays set if we had.
|
|
*/
|
|
if (value & X86_EFLAGS_TF)
|
|
clear_tsk_thread_flag(task, TIF_FORCED_TF);
|
|
else if (test_tsk_thread_flag(task, TIF_FORCED_TF))
|
|
value |= X86_EFLAGS_TF;
|
|
|
|
regs->flags = (regs->flags & ~FLAG_MASK) | (value & FLAG_MASK);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int putreg(struct task_struct *child,
|
|
unsigned long offset, unsigned long value)
|
|
{
|
|
switch (offset) {
|
|
case offsetof(struct user_regs_struct, cs):
|
|
case offsetof(struct user_regs_struct, ds):
|
|
case offsetof(struct user_regs_struct, es):
|
|
case offsetof(struct user_regs_struct, fs):
|
|
case offsetof(struct user_regs_struct, gs):
|
|
case offsetof(struct user_regs_struct, ss):
|
|
return set_segment_reg(child, offset, value);
|
|
|
|
case offsetof(struct user_regs_struct, flags):
|
|
return set_flags(child, value);
|
|
}
|
|
|
|
*pt_regs_access(task_pt_regs(child), offset) = value;
|
|
return 0;
|
|
}
|
|
|
|
static unsigned long getreg(struct task_struct *task, unsigned long offset)
|
|
{
|
|
switch (offset) {
|
|
case offsetof(struct user_regs_struct, cs):
|
|
case offsetof(struct user_regs_struct, ds):
|
|
case offsetof(struct user_regs_struct, es):
|
|
case offsetof(struct user_regs_struct, fs):
|
|
case offsetof(struct user_regs_struct, gs):
|
|
case offsetof(struct user_regs_struct, ss):
|
|
return get_segment_reg(task, offset);
|
|
|
|
case offsetof(struct user_regs_struct, flags):
|
|
return get_flags(task);
|
|
}
|
|
|
|
return *pt_regs_access(task_pt_regs(task), offset);
|
|
}
|
|
|
|
/*
|
|
* This function is trivial and will be inlined by the compiler.
|
|
* Having it separates the implementation details of debug
|
|
* registers from the interface details of ptrace.
|
|
*/
|
|
static unsigned long ptrace_get_debugreg(struct task_struct *child, int n)
|
|
{
|
|
switch (n) {
|
|
case 0: return child->thread.debugreg0;
|
|
case 1: return child->thread.debugreg1;
|
|
case 2: return child->thread.debugreg2;
|
|
case 3: return child->thread.debugreg3;
|
|
case 6: return child->thread.debugreg6;
|
|
case 7: return child->thread.debugreg7;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static int ptrace_set_debugreg(struct task_struct *child,
|
|
int n, unsigned long data)
|
|
{
|
|
int i;
|
|
|
|
if (unlikely(n == 4 || n == 5))
|
|
return -EIO;
|
|
|
|
if (n < 4 && unlikely(data >= TASK_SIZE - 3))
|
|
return -EIO;
|
|
|
|
switch (n) {
|
|
case 0: child->thread.debugreg0 = data; break;
|
|
case 1: child->thread.debugreg1 = data; break;
|
|
case 2: child->thread.debugreg2 = data; break;
|
|
case 3: child->thread.debugreg3 = data; break;
|
|
|
|
case 6:
|
|
child->thread.debugreg6 = data;
|
|
break;
|
|
|
|
case 7:
|
|
/*
|
|
* Sanity-check data. Take one half-byte at once with
|
|
* check = (val >> (16 + 4*i)) & 0xf. It contains the
|
|
* R/Wi and LENi bits; bits 0 and 1 are R/Wi, and bits
|
|
* 2 and 3 are LENi. Given a list of invalid values,
|
|
* we do mask |= 1 << invalid_value, so that
|
|
* (mask >> check) & 1 is a correct test for invalid
|
|
* values.
|
|
*
|
|
* R/Wi contains the type of the breakpoint /
|
|
* watchpoint, LENi contains the length of the watched
|
|
* data in the watchpoint case.
|
|
*
|
|
* The invalid values are:
|
|
* - LENi == 0x10 (undefined), so mask |= 0x0f00.
|
|
* - R/Wi == 0x10 (break on I/O reads or writes), so
|
|
* mask |= 0x4444.
|
|
* - R/Wi == 0x00 && LENi != 0x00, so we have mask |=
|
|
* 0x1110.
|
|
*
|
|
* Finally, mask = 0x0f00 | 0x4444 | 0x1110 == 0x5f54.
|
|
*
|
|
* See the Intel Manual "System Programming Guide",
|
|
* 15.2.4
|
|
*
|
|
* Note that LENi == 0x10 is defined on x86_64 in long
|
|
* mode (i.e. even for 32-bit userspace software, but
|
|
* 64-bit kernel), so the x86_64 mask value is 0x5454.
|
|
* See the AMD manual no. 24593 (AMD64 System Programming)
|
|
*/
|
|
data &= ~DR_CONTROL_RESERVED;
|
|
for (i = 0; i < 4; i++)
|
|
if ((0x5f54 >> ((data >> (16 + 4*i)) & 0xf)) & 1)
|
|
return -EIO;
|
|
child->thread.debugreg7 = data;
|
|
if (data)
|
|
set_tsk_thread_flag(child, TIF_DEBUG);
|
|
else
|
|
clear_tsk_thread_flag(child, TIF_DEBUG);
|
|
break;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Called by kernel/ptrace.c when detaching..
|
|
*
|
|
* Make sure the single step bit is not set.
|
|
*/
|
|
void ptrace_disable(struct task_struct *child)
|
|
{
|
|
user_disable_single_step(child);
|
|
clear_tsk_thread_flag(child, TIF_SYSCALL_EMU);
|
|
}
|
|
|
|
long arch_ptrace(struct task_struct *child, long request, long addr, long data)
|
|
{
|
|
struct user * dummy = NULL;
|
|
int i, ret;
|
|
unsigned long __user *datap = (unsigned long __user *)data;
|
|
|
|
switch (request) {
|
|
/* when I and D space are separate, these will need to be fixed. */
|
|
case PTRACE_PEEKTEXT: /* read word at location addr. */
|
|
case PTRACE_PEEKDATA:
|
|
ret = generic_ptrace_peekdata(child, addr, data);
|
|
break;
|
|
|
|
/* read the word at location addr in the USER area. */
|
|
case PTRACE_PEEKUSR: {
|
|
unsigned long tmp;
|
|
|
|
ret = -EIO;
|
|
if ((addr & 3) || addr < 0 ||
|
|
addr > sizeof(struct user) - 3)
|
|
break;
|
|
|
|
tmp = 0; /* Default return condition */
|
|
if(addr < FRAME_SIZE*sizeof(long))
|
|
tmp = getreg(child, addr);
|
|
if(addr >= (long) &dummy->u_debugreg[0] &&
|
|
addr <= (long) &dummy->u_debugreg[7]){
|
|
addr -= (long) &dummy->u_debugreg[0];
|
|
addr = addr >> 2;
|
|
tmp = ptrace_get_debugreg(child, addr);
|
|
}
|
|
ret = put_user(tmp, datap);
|
|
break;
|
|
}
|
|
|
|
/* when I and D space are separate, this will have to be fixed. */
|
|
case PTRACE_POKETEXT: /* write the word at location addr. */
|
|
case PTRACE_POKEDATA:
|
|
ret = generic_ptrace_pokedata(child, addr, data);
|
|
break;
|
|
|
|
case PTRACE_POKEUSR: /* write the word at location addr in the USER area */
|
|
ret = -EIO;
|
|
if ((addr & 3) || addr < 0 ||
|
|
addr > sizeof(struct user) - 3)
|
|
break;
|
|
|
|
if (addr < FRAME_SIZE*sizeof(long)) {
|
|
ret = putreg(child, addr, data);
|
|
break;
|
|
}
|
|
/* We need to be very careful here. We implicitly
|
|
want to modify a portion of the task_struct, and we
|
|
have to be selective about what portions we allow someone
|
|
to modify. */
|
|
|
|
ret = -EIO;
|
|
if(addr >= (long) &dummy->u_debugreg[0] &&
|
|
addr <= (long) &dummy->u_debugreg[7]){
|
|
addr -= (long) &dummy->u_debugreg;
|
|
addr = addr >> 2;
|
|
ret = ptrace_set_debugreg(child, addr, data);
|
|
}
|
|
break;
|
|
|
|
case PTRACE_GETREGS: { /* Get all gp regs from the child. */
|
|
if (!access_ok(VERIFY_WRITE, datap, FRAME_SIZE*sizeof(long))) {
|
|
ret = -EIO;
|
|
break;
|
|
}
|
|
for ( i = 0; i < FRAME_SIZE*sizeof(long); i += sizeof(long) ) {
|
|
__put_user(getreg(child, i), datap);
|
|
datap++;
|
|
}
|
|
ret = 0;
|
|
break;
|
|
}
|
|
|
|
case PTRACE_SETREGS: { /* Set all gp regs in the child. */
|
|
unsigned long tmp;
|
|
if (!access_ok(VERIFY_READ, datap, FRAME_SIZE*sizeof(long))) {
|
|
ret = -EIO;
|
|
break;
|
|
}
|
|
for ( i = 0; i < FRAME_SIZE*sizeof(long); i += sizeof(long) ) {
|
|
__get_user(tmp, datap);
|
|
putreg(child, i, tmp);
|
|
datap++;
|
|
}
|
|
ret = 0;
|
|
break;
|
|
}
|
|
|
|
case PTRACE_GETFPREGS: { /* Get the child FPU state. */
|
|
if (!access_ok(VERIFY_WRITE, datap,
|
|
sizeof(struct user_i387_struct))) {
|
|
ret = -EIO;
|
|
break;
|
|
}
|
|
ret = 0;
|
|
if (!tsk_used_math(child))
|
|
init_fpu(child);
|
|
get_fpregs((struct user_i387_struct __user *)data, child);
|
|
break;
|
|
}
|
|
|
|
case PTRACE_SETFPREGS: { /* Set the child FPU state. */
|
|
if (!access_ok(VERIFY_READ, datap,
|
|
sizeof(struct user_i387_struct))) {
|
|
ret = -EIO;
|
|
break;
|
|
}
|
|
set_stopped_child_used_math(child);
|
|
set_fpregs(child, (struct user_i387_struct __user *)data);
|
|
ret = 0;
|
|
break;
|
|
}
|
|
|
|
case PTRACE_GETFPXREGS: { /* Get the child extended FPU state. */
|
|
if (!access_ok(VERIFY_WRITE, datap,
|
|
sizeof(struct user_fxsr_struct))) {
|
|
ret = -EIO;
|
|
break;
|
|
}
|
|
if (!tsk_used_math(child))
|
|
init_fpu(child);
|
|
ret = get_fpxregs((struct user_fxsr_struct __user *)data, child);
|
|
break;
|
|
}
|
|
|
|
case PTRACE_SETFPXREGS: { /* Set the child extended FPU state. */
|
|
if (!access_ok(VERIFY_READ, datap,
|
|
sizeof(struct user_fxsr_struct))) {
|
|
ret = -EIO;
|
|
break;
|
|
}
|
|
set_stopped_child_used_math(child);
|
|
ret = set_fpxregs(child, (struct user_fxsr_struct __user *)data);
|
|
break;
|
|
}
|
|
|
|
case PTRACE_GET_THREAD_AREA:
|
|
if (addr < 0)
|
|
return -EIO;
|
|
ret = do_get_thread_area(child, addr,
|
|
(struct user_desc __user *) data);
|
|
break;
|
|
|
|
case PTRACE_SET_THREAD_AREA:
|
|
if (addr < 0)
|
|
return -EIO;
|
|
ret = do_set_thread_area(child, addr,
|
|
(struct user_desc __user *) data, 0);
|
|
break;
|
|
|
|
default:
|
|
ret = ptrace_request(child, request, addr, data);
|
|
break;
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
void send_sigtrap(struct task_struct *tsk, struct pt_regs *regs, int error_code)
|
|
{
|
|
struct siginfo info;
|
|
|
|
tsk->thread.trap_no = 1;
|
|
tsk->thread.error_code = error_code;
|
|
|
|
memset(&info, 0, sizeof(info));
|
|
info.si_signo = SIGTRAP;
|
|
info.si_code = TRAP_BRKPT;
|
|
|
|
/* User-mode ip? */
|
|
info.si_addr = user_mode_vm(regs) ? (void __user *) regs->ip : NULL;
|
|
|
|
/* Send us the fake SIGTRAP */
|
|
force_sig_info(SIGTRAP, &info, tsk);
|
|
}
|
|
|
|
/* notification of system call entry/exit
|
|
* - triggered by current->work.syscall_trace
|
|
*/
|
|
__attribute__((regparm(3)))
|
|
int do_syscall_trace(struct pt_regs *regs, int entryexit)
|
|
{
|
|
int is_sysemu = test_thread_flag(TIF_SYSCALL_EMU);
|
|
/*
|
|
* With TIF_SYSCALL_EMU set we want to ignore TIF_SINGLESTEP for syscall
|
|
* interception
|
|
*/
|
|
int is_singlestep = !is_sysemu && test_thread_flag(TIF_SINGLESTEP);
|
|
int ret = 0;
|
|
|
|
/* do the secure computing check first */
|
|
if (!entryexit)
|
|
secure_computing(regs->orig_ax);
|
|
|
|
if (unlikely(current->audit_context)) {
|
|
if (entryexit)
|
|
audit_syscall_exit(AUDITSC_RESULT(regs->ax),
|
|
regs->ax);
|
|
/* Debug traps, when using PTRACE_SINGLESTEP, must be sent only
|
|
* on the syscall exit path. Normally, when TIF_SYSCALL_AUDIT is
|
|
* not used, entry.S will call us only on syscall exit, not
|
|
* entry; so when TIF_SYSCALL_AUDIT is used we must avoid
|
|
* calling send_sigtrap() on syscall entry.
|
|
*
|
|
* Note that when PTRACE_SYSEMU_SINGLESTEP is used,
|
|
* is_singlestep is false, despite his name, so we will still do
|
|
* the correct thing.
|
|
*/
|
|
else if (is_singlestep)
|
|
goto out;
|
|
}
|
|
|
|
if (!(current->ptrace & PT_PTRACED))
|
|
goto out;
|
|
|
|
/* If a process stops on the 1st tracepoint with SYSCALL_TRACE
|
|
* and then is resumed with SYSEMU_SINGLESTEP, it will come in
|
|
* here. We have to check this and return */
|
|
if (is_sysemu && entryexit)
|
|
return 0;
|
|
|
|
/* Fake a debug trap */
|
|
if (is_singlestep)
|
|
send_sigtrap(current, regs, 0);
|
|
|
|
if (!test_thread_flag(TIF_SYSCALL_TRACE) && !is_sysemu)
|
|
goto out;
|
|
|
|
/* the 0x80 provides a way for the tracing parent to distinguish
|
|
between a syscall stop and SIGTRAP delivery */
|
|
/* Note that the debugger could change the result of test_thread_flag!*/
|
|
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;
|
|
}
|
|
ret = is_sysemu;
|
|
out:
|
|
if (unlikely(current->audit_context) && !entryexit)
|
|
audit_syscall_entry(AUDIT_ARCH_I386, regs->orig_ax,
|
|
regs->bx, regs->cx, regs->dx, regs->si);
|
|
if (ret == 0)
|
|
return 0;
|
|
|
|
regs->orig_ax = -1; /* force skip of syscall restarting */
|
|
if (unlikely(current->audit_context))
|
|
audit_syscall_exit(AUDITSC_RESULT(regs->ax), regs->ax);
|
|
return 1;
|
|
}
|