linux-stable/arch/xtensa/kernel/ptrace.c
Eric W. Biederman f71dd7dc2d signal/ptrace: Add force_sig_ptrace_errno_trap and use it where needed
There are so many places that build struct siginfo by hand that at
least one of them is bound to get it wrong.  A handful of cases in the
kernel arguably did just that when using the errno field of siginfo to
pass no errno values to userspace.  The usage is limited to a single
si_code so at least does not mess up anything else.

Encapsulate this questionable pattern in a helper function so
that the userspace ABI is preserved.

Update all of the places that use this pattern to use the new helper
function.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2018-01-22 19:07:11 -06:00

483 lines
11 KiB
C

/*
* 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/errno.h>
#include <linux/hw_breakpoint.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/perf_event.h>
#include <linux/ptrace.h>
#include <linux/sched.h>
#include <linux/sched/task_stack.h>
#include <linux/security.h>
#include <linux/signal.h>
#include <linux/smp.h>
#include <linux/tracehook.h>
#include <linux/uaccess.h>
#include <asm/coprocessor.h>
#include <asm/elf.h>
#include <asm/page.h>
#include <asm/pgtable.h>
#include <asm/ptrace.h>
void user_enable_single_step(struct task_struct *child)
{
child->ptrace |= PT_SINGLESTEP;
}
void user_disable_single_step(struct task_struct *child)
{
child->ptrace &= ~PT_SINGLESTEP;
}
/*
* Called by kernel/ptrace.c when detaching to disable single stepping.
*/
void ptrace_disable(struct task_struct *child)
{
/* Nothing to do.. */
}
static 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 wb = regs->windowbase;
int 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);
__put_user(regs->threadptr, &gregset->threadptr);
for (i = 0; i < XCHAL_NUM_AREGS; i++)
__put_user(regs->areg[i],
gregset->a + ((wb * 4 + i) % XCHAL_NUM_AREGS));
return 0;
}
static 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, ws;
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(ws, &gregset->windowstart);
__get_user(wb, &gregset->windowbase);
__get_user(regs->threadptr, &gregset->threadptr);
regs->ps = (regs->ps & ~ps_mask) | (ps & ps_mask) | (1 << PS_EXCM_BIT);
if (wb >= XCHAL_NUM_AREGS / 4)
return -EFAULT;
if (wb != regs->windowbase || ws != regs->windowstart) {
unsigned long rotws, wmask;
rotws = (((ws | (ws << WSBITS)) >> wb) &
((1 << WSBITS) - 1)) & ~1;
wmask = ((rotws ? WSBITS + 1 - ffs(rotws) : 0) << 4) |
(rotws & 0xF) | 1;
regs->windowbase = wb;
regs->windowstart = ws;
regs->wmask = wmask;
}
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;
}
static 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;
}
static 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 (!access_ok(VERIFY_READ, uregs, sizeof(elf_xtregs_t)))
return -EFAULT;
#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;
}
static 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);
}
static 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;
}
#ifdef CONFIG_HAVE_HW_BREAKPOINT
static void ptrace_hbptriggered(struct perf_event *bp,
struct perf_sample_data *data,
struct pt_regs *regs)
{
int i;
struct arch_hw_breakpoint *bkpt = counter_arch_bp(bp);
if (bp->attr.bp_type & HW_BREAKPOINT_X) {
for (i = 0; i < XCHAL_NUM_IBREAK; ++i)
if (current->thread.ptrace_bp[i] == bp)
break;
i <<= 1;
} else {
for (i = 0; i < XCHAL_NUM_DBREAK; ++i)
if (current->thread.ptrace_wp[i] == bp)
break;
i = (i << 1) | 1;
}
force_sig_ptrace_errno_trap(i, (void __user *)bkpt->address);
}
static struct perf_event *ptrace_hbp_create(struct task_struct *tsk, int type)
{
struct perf_event_attr attr;
ptrace_breakpoint_init(&attr);
/* Initialise fields to sane defaults. */
attr.bp_addr = 0;
attr.bp_len = 1;
attr.bp_type = type;
attr.disabled = 1;
return register_user_hw_breakpoint(&attr, ptrace_hbptriggered, NULL,
tsk);
}
/*
* Address bit 0 choose instruction (0) or data (1) break register, bits
* 31..1 are the register number.
* Both PTRACE_GETHBPREGS and PTRACE_SETHBPREGS transfer two 32-bit words:
* address (0) and control (1).
* Instruction breakpoint contorl word is 0 to clear breakpoint, 1 to set.
* Data breakpoint control word bit 31 is 'trigger on store', bit 30 is
* 'trigger on load, bits 29..0 are length. Length 0 is used to clear a
* breakpoint. To set a breakpoint length must be a power of 2 in the range
* 1..64 and the address must be length-aligned.
*/
static long ptrace_gethbpregs(struct task_struct *child, long addr,
long __user *datap)
{
struct perf_event *bp;
u32 user_data[2] = {0};
bool dbreak = addr & 1;
unsigned idx = addr >> 1;
if ((!dbreak && idx >= XCHAL_NUM_IBREAK) ||
(dbreak && idx >= XCHAL_NUM_DBREAK))
return -EINVAL;
if (dbreak)
bp = child->thread.ptrace_wp[idx];
else
bp = child->thread.ptrace_bp[idx];
if (bp) {
user_data[0] = bp->attr.bp_addr;
user_data[1] = bp->attr.disabled ? 0 : bp->attr.bp_len;
if (dbreak) {
if (bp->attr.bp_type & HW_BREAKPOINT_R)
user_data[1] |= DBREAKC_LOAD_MASK;
if (bp->attr.bp_type & HW_BREAKPOINT_W)
user_data[1] |= DBREAKC_STOR_MASK;
}
}
if (copy_to_user(datap, user_data, sizeof(user_data)))
return -EFAULT;
return 0;
}
static long ptrace_sethbpregs(struct task_struct *child, long addr,
long __user *datap)
{
struct perf_event *bp;
struct perf_event_attr attr;
u32 user_data[2];
bool dbreak = addr & 1;
unsigned idx = addr >> 1;
int bp_type = 0;
if ((!dbreak && idx >= XCHAL_NUM_IBREAK) ||
(dbreak && idx >= XCHAL_NUM_DBREAK))
return -EINVAL;
if (copy_from_user(user_data, datap, sizeof(user_data)))
return -EFAULT;
if (dbreak) {
bp = child->thread.ptrace_wp[idx];
if (user_data[1] & DBREAKC_LOAD_MASK)
bp_type |= HW_BREAKPOINT_R;
if (user_data[1] & DBREAKC_STOR_MASK)
bp_type |= HW_BREAKPOINT_W;
} else {
bp = child->thread.ptrace_bp[idx];
bp_type = HW_BREAKPOINT_X;
}
if (!bp) {
bp = ptrace_hbp_create(child,
bp_type ? bp_type : HW_BREAKPOINT_RW);
if (IS_ERR(bp))
return PTR_ERR(bp);
if (dbreak)
child->thread.ptrace_wp[idx] = bp;
else
child->thread.ptrace_bp[idx] = bp;
}
attr = bp->attr;
attr.bp_addr = user_data[0];
attr.bp_len = user_data[1] & ~(DBREAKC_LOAD_MASK | DBREAKC_STOR_MASK);
attr.bp_type = bp_type;
attr.disabled = !attr.bp_len;
return modify_user_hw_breakpoint(bp, &attr);
}
#endif
long arch_ptrace(struct task_struct *child, long request,
unsigned long addr, unsigned long data)
{
int ret = -EPERM;
void __user *datap = (void __user *) data;
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, datap);
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;
case PTRACE_GETREGS:
ret = ptrace_getregs(child, datap);
break;
case PTRACE_SETREGS:
ret = ptrace_setregs(child, datap);
break;
case PTRACE_GETXTREGS:
ret = ptrace_getxregs(child, datap);
break;
case PTRACE_SETXTREGS:
ret = ptrace_setxregs(child, datap);
break;
#ifdef CONFIG_HAVE_HW_BREAKPOINT
case PTRACE_GETHBPREGS:
ret = ptrace_gethbpregs(child, addr, datap);
break;
case PTRACE_SETHBPREGS:
ret = ptrace_sethbpregs(child, addr, datap);
break;
#endif
default:
ret = ptrace_request(child, request, addr, data);
break;
}
return ret;
}
unsigned long do_syscall_trace_enter(struct pt_regs *regs)
{
if (test_thread_flag(TIF_SYSCALL_TRACE) &&
tracehook_report_syscall_entry(regs))
return -1;
return regs->areg[2];
}
void do_syscall_trace_leave(struct pt_regs *regs)
{
int step;
step = test_thread_flag(TIF_SINGLESTEP);
if (step || test_thread_flag(TIF_SYSCALL_TRACE))
tracehook_report_syscall_exit(regs, step);
}