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linux/arch/powerpc/kernel/ptrace/ptrace.c

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/*
* PowerPC version
* Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
*
* Derived from "arch/m68k/kernel/ptrace.c"
* Copyright (C) 1994 by Hamish Macdonald
* Taken from linux/kernel/ptrace.c and modified for M680x0.
* linux/kernel/ptrace.c is by Ross Biro 1/23/92, edited by Linus Torvalds
*
* Modified by Cort Dougan (cort@hq.fsmlabs.com)
* and Paul Mackerras (paulus@samba.org).
*
* This file is subject to the terms and conditions of the GNU General
* Public License. See the file README.legal in the main directory of
* this archive for more details.
*/
#include <linux/regset.h>
#include <linux/tracehook.h>
#include <linux/audit.h>
#include <linux/context_tracking.h>
#include <linux/syscalls.h>
#include <asm/switch_to.h>
#include <asm/asm-prototypes.h>
#include <asm/debug.h>
#define CREATE_TRACE_POINTS
#include <trace/events/syscalls.h>
#include "ptrace-decl.h"
/*
* Called by kernel/ptrace.c when detaching..
*
* Make sure single step bits etc are not set.
*/
void ptrace_disable(struct task_struct *child)
{
/* make sure the single step bit is not set. */
user_disable_single_step(child);
}
long arch_ptrace(struct task_struct *child, long request,
unsigned long addr, unsigned long data)
{
int ret = -EPERM;
void __user *datavp = (void __user *) data;
unsigned long __user *datalp = datavp;
switch (request) {
/* read the word at location addr in the USER area. */
case PTRACE_PEEKUSR: {
unsigned long index, tmp;
ret = -EIO;
/* convert to index and check */
#ifdef CONFIG_PPC32
index = addr >> 2;
if ((addr & 3) || (index > PT_FPSCR)
|| (child->thread.regs == NULL))
#else
index = addr >> 3;
if ((addr & 7) || (index > PT_FPSCR))
#endif
break;
CHECK_FULL_REGS(child->thread.regs);
if (index < PT_FPR0) {
ret = ptrace_get_reg(child, (int) index, &tmp);
if (ret)
break;
} else {
unsigned int fpidx = index - PT_FPR0;
flush_fp_to_thread(child);
if (fpidx < (PT_FPSCR - PT_FPR0))
memcpy(&tmp, &child->thread.TS_FPR(fpidx),
sizeof(long));
else
tmp = child->thread.fp_state.fpscr;
}
ret = put_user(tmp, datalp);
break;
}
/* write the word at location addr in the USER area */
case PTRACE_POKEUSR: {
unsigned long index;
ret = -EIO;
/* convert to index and check */
#ifdef CONFIG_PPC32
index = addr >> 2;
if ((addr & 3) || (index > PT_FPSCR)
|| (child->thread.regs == NULL))
#else
index = addr >> 3;
if ((addr & 7) || (index > PT_FPSCR))
#endif
break;
CHECK_FULL_REGS(child->thread.regs);
if (index < PT_FPR0) {
ret = ptrace_put_reg(child, index, data);
} else {
unsigned int fpidx = index - PT_FPR0;
flush_fp_to_thread(child);
if (fpidx < (PT_FPSCR - PT_FPR0))
memcpy(&child->thread.TS_FPR(fpidx), &data,
sizeof(long));
else
child->thread.fp_state.fpscr = data;
ret = 0;
}
break;
}
case PPC_PTRACE_GETHWDBGINFO: {
struct ppc_debug_info dbginfo;
ppc_gethwdinfo(&dbginfo);
if (copy_to_user(datavp, &dbginfo,
sizeof(struct ppc_debug_info)))
return -EFAULT;
return 0;
}
case PPC_PTRACE_SETHWDEBUG: {
struct ppc_hw_breakpoint bp_info;
if (copy_from_user(&bp_info, datavp,
sizeof(struct ppc_hw_breakpoint)))
return -EFAULT;
return ppc_set_hwdebug(child, &bp_info);
}
case PPC_PTRACE_DELHWDEBUG: {
ret = ppc_del_hwdebug(child, data);
break;
}
case PTRACE_GET_DEBUGREG:
ret = ptrace_get_debugreg(child, addr, datalp);
break;
case PTRACE_SET_DEBUGREG:
ret = ptrace_set_debugreg(child, addr, data);
break;
#ifdef CONFIG_PPC64
case PTRACE_GETREGS64:
#endif
case PTRACE_GETREGS: /* Get all pt_regs from the child. */
return copy_regset_to_user(child, &user_ppc_native_view,
REGSET_GPR,
0, sizeof(struct user_pt_regs),
datavp);
#ifdef CONFIG_PPC64
case PTRACE_SETREGS64:
#endif
case PTRACE_SETREGS: /* Set all gp regs in the child. */
return copy_regset_from_user(child, &user_ppc_native_view,
REGSET_GPR,
0, sizeof(struct user_pt_regs),
datavp);
case PTRACE_GETFPREGS: /* Get the child FPU state (FPR0...31 + FPSCR) */
return copy_regset_to_user(child, &user_ppc_native_view,
REGSET_FPR,
0, sizeof(elf_fpregset_t),
datavp);
case PTRACE_SETFPREGS: /* Set the child FPU state (FPR0...31 + FPSCR) */
return copy_regset_from_user(child, &user_ppc_native_view,
REGSET_FPR,
0, sizeof(elf_fpregset_t),
datavp);
#ifdef CONFIG_ALTIVEC
case PTRACE_GETVRREGS:
return copy_regset_to_user(child, &user_ppc_native_view,
REGSET_VMX,
0, (33 * sizeof(vector128) +
sizeof(u32)),
datavp);
case PTRACE_SETVRREGS:
return copy_regset_from_user(child, &user_ppc_native_view,
REGSET_VMX,
0, (33 * sizeof(vector128) +
sizeof(u32)),
datavp);
#endif
#ifdef CONFIG_VSX
case PTRACE_GETVSRREGS:
return copy_regset_to_user(child, &user_ppc_native_view,
REGSET_VSX,
0, 32 * sizeof(double),
datavp);
case PTRACE_SETVSRREGS:
return copy_regset_from_user(child, &user_ppc_native_view,
REGSET_VSX,
0, 32 * sizeof(double),
datavp);
#endif
#ifdef CONFIG_SPE
case PTRACE_GETEVRREGS:
/* Get the child spe register state. */
return copy_regset_to_user(child, &user_ppc_native_view,
REGSET_SPE, 0, 35 * sizeof(u32),
datavp);
case PTRACE_SETEVRREGS:
/* Set the child spe register state. */
return copy_regset_from_user(child, &user_ppc_native_view,
REGSET_SPE, 0, 35 * sizeof(u32),
datavp);
#endif
default:
ret = ptrace_request(child, request, addr, data);
break;
}
return ret;
}
#ifdef CONFIG_SECCOMP
static int do_seccomp(struct pt_regs *regs)
{
if (!test_thread_flag(TIF_SECCOMP))
return 0;
/*
* The ABI we present to seccomp tracers is that r3 contains
* the syscall return value and orig_gpr3 contains the first
* syscall parameter. This is different to the ptrace ABI where
* both r3 and orig_gpr3 contain the first syscall parameter.
*/
regs->gpr[3] = -ENOSYS;
/*
* We use the __ version here because we have already checked
* TIF_SECCOMP. If this fails, there is nothing left to do, we
* have already loaded -ENOSYS into r3, or seccomp has put
* something else in r3 (via SECCOMP_RET_ERRNO/TRACE).
*/
if (__secure_computing(NULL))
return -1;
/*
* The syscall was allowed by seccomp, restore the register
* state to what audit expects.
* Note that we use orig_gpr3, which means a seccomp tracer can
* modify the first syscall parameter (in orig_gpr3) and also
* allow the syscall to proceed.
*/
regs->gpr[3] = regs->orig_gpr3;
return 0;
}
#else
static inline int do_seccomp(struct pt_regs *regs) { return 0; }
#endif /* CONFIG_SECCOMP */
/**
* do_syscall_trace_enter() - Do syscall tracing on kernel entry.
* @regs: the pt_regs of the task to trace (current)
*
* Performs various types of tracing on syscall entry. This includes seccomp,
* ptrace, syscall tracepoints and audit.
*
* The pt_regs are potentially visible to userspace via ptrace, so their
* contents is ABI.
*
* One or more of the tracers may modify the contents of pt_regs, in particular
* to modify arguments or even the syscall number itself.
*
* It's also possible that a tracer can choose to reject the system call. In
* that case this function will return an illegal syscall number, and will put
* an appropriate return value in regs->r3.
*
* Return: the (possibly changed) syscall number.
*/
long do_syscall_trace_enter(struct pt_regs *regs)
{
u32 flags;
user_exit();
flags = READ_ONCE(current_thread_info()->flags) &
(_TIF_SYSCALL_EMU | _TIF_SYSCALL_TRACE);
if (flags) {
int rc = tracehook_report_syscall_entry(regs);
if (unlikely(flags & _TIF_SYSCALL_EMU)) {
/*
* A nonzero return code from
* tracehook_report_syscall_entry() tells us to prevent
* the syscall execution, but we are not going to
* execute it anyway.
*
* Returning -1 will skip the syscall execution. We want
* to avoid clobbering any registers, so we don't goto
* the skip label below.
*/
return -1;
}
if (rc) {
/*
* The tracer decided to abort the syscall. Note that
* the tracer may also just change regs->gpr[0] to an
* invalid syscall number, that is handled below on the
* exit path.
*/
goto skip;
}
}
/* Run seccomp after ptrace; allow it to set gpr[3]. */
if (do_seccomp(regs))
return -1;
/* Avoid trace and audit when syscall is invalid. */
if (regs->gpr[0] >= NR_syscalls)
goto skip;
if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
trace_sys_enter(regs, regs->gpr[0]);
if (!is_32bit_task())
audit_syscall_entry(regs->gpr[0], regs->gpr[3], regs->gpr[4],
regs->gpr[5], regs->gpr[6]);
else
audit_syscall_entry(regs->gpr[0],
regs->gpr[3] & 0xffffffff,
regs->gpr[4] & 0xffffffff,
regs->gpr[5] & 0xffffffff,
regs->gpr[6] & 0xffffffff);
/* Return the possibly modified but valid syscall number */
return regs->gpr[0];
skip:
/*
* If we are aborting explicitly, or if the syscall number is
* now invalid, set the return value to -ENOSYS.
*/
regs->gpr[3] = -ENOSYS;
return -1;
}
void do_syscall_trace_leave(struct pt_regs *regs)
{
int step;
audit_syscall_exit(regs);
if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
trace_sys_exit(regs, regs->result);
step = test_thread_flag(TIF_SINGLESTEP);
if (step || test_thread_flag(TIF_SYSCALL_TRACE))
tracehook_report_syscall_exit(regs, step);
user_enter();
}
void __init pt_regs_check(void);
/*
* Dummy function, its purpose is to break the build if struct pt_regs and
* struct user_pt_regs don't match.
*/
void __init pt_regs_check(void)
{
BUILD_BUG_ON(offsetof(struct pt_regs, gpr) !=
offsetof(struct user_pt_regs, gpr));
BUILD_BUG_ON(offsetof(struct pt_regs, nip) !=
offsetof(struct user_pt_regs, nip));
BUILD_BUG_ON(offsetof(struct pt_regs, msr) !=
offsetof(struct user_pt_regs, msr));
BUILD_BUG_ON(offsetof(struct pt_regs, msr) !=
offsetof(struct user_pt_regs, msr));
BUILD_BUG_ON(offsetof(struct pt_regs, orig_gpr3) !=
offsetof(struct user_pt_regs, orig_gpr3));
BUILD_BUG_ON(offsetof(struct pt_regs, ctr) !=
offsetof(struct user_pt_regs, ctr));
BUILD_BUG_ON(offsetof(struct pt_regs, link) !=
offsetof(struct user_pt_regs, link));
BUILD_BUG_ON(offsetof(struct pt_regs, xer) !=
offsetof(struct user_pt_regs, xer));
BUILD_BUG_ON(offsetof(struct pt_regs, ccr) !=
offsetof(struct user_pt_regs, ccr));
#ifdef __powerpc64__
BUILD_BUG_ON(offsetof(struct pt_regs, softe) !=
offsetof(struct user_pt_regs, softe));
#else
BUILD_BUG_ON(offsetof(struct pt_regs, mq) !=
offsetof(struct user_pt_regs, mq));
#endif
BUILD_BUG_ON(offsetof(struct pt_regs, trap) !=
offsetof(struct user_pt_regs, trap));
BUILD_BUG_ON(offsetof(struct pt_regs, dar) !=
offsetof(struct user_pt_regs, dar));
BUILD_BUG_ON(offsetof(struct pt_regs, dsisr) !=
offsetof(struct user_pt_regs, dsisr));
BUILD_BUG_ON(offsetof(struct pt_regs, result) !=
offsetof(struct user_pt_regs, result));
BUILD_BUG_ON(sizeof(struct user_pt_regs) > sizeof(struct pt_regs));
// Now check that the pt_regs offsets match the uapi #defines
#define CHECK_REG(_pt, _reg) \
BUILD_BUG_ON(_pt != (offsetof(struct user_pt_regs, _reg) / \
sizeof(unsigned long)));
CHECK_REG(PT_R0, gpr[0]);
CHECK_REG(PT_R1, gpr[1]);
CHECK_REG(PT_R2, gpr[2]);
CHECK_REG(PT_R3, gpr[3]);
CHECK_REG(PT_R4, gpr[4]);
CHECK_REG(PT_R5, gpr[5]);
CHECK_REG(PT_R6, gpr[6]);
CHECK_REG(PT_R7, gpr[7]);
CHECK_REG(PT_R8, gpr[8]);
CHECK_REG(PT_R9, gpr[9]);
CHECK_REG(PT_R10, gpr[10]);
CHECK_REG(PT_R11, gpr[11]);
CHECK_REG(PT_R12, gpr[12]);
CHECK_REG(PT_R13, gpr[13]);
CHECK_REG(PT_R14, gpr[14]);
CHECK_REG(PT_R15, gpr[15]);
CHECK_REG(PT_R16, gpr[16]);
CHECK_REG(PT_R17, gpr[17]);
CHECK_REG(PT_R18, gpr[18]);
CHECK_REG(PT_R19, gpr[19]);
CHECK_REG(PT_R20, gpr[20]);
CHECK_REG(PT_R21, gpr[21]);
CHECK_REG(PT_R22, gpr[22]);
CHECK_REG(PT_R23, gpr[23]);
CHECK_REG(PT_R24, gpr[24]);
CHECK_REG(PT_R25, gpr[25]);
CHECK_REG(PT_R26, gpr[26]);
CHECK_REG(PT_R27, gpr[27]);
CHECK_REG(PT_R28, gpr[28]);
CHECK_REG(PT_R29, gpr[29]);
CHECK_REG(PT_R30, gpr[30]);
CHECK_REG(PT_R31, gpr[31]);
CHECK_REG(PT_NIP, nip);
CHECK_REG(PT_MSR, msr);
CHECK_REG(PT_ORIG_R3, orig_gpr3);
CHECK_REG(PT_CTR, ctr);
CHECK_REG(PT_LNK, link);
CHECK_REG(PT_XER, xer);
CHECK_REG(PT_CCR, ccr);
#ifdef CONFIG_PPC64
CHECK_REG(PT_SOFTE, softe);
#else
CHECK_REG(PT_MQ, mq);
#endif
CHECK_REG(PT_TRAP, trap);
CHECK_REG(PT_DAR, dar);
CHECK_REG(PT_DSISR, dsisr);
CHECK_REG(PT_RESULT, result);
#undef CHECK_REG
BUILD_BUG_ON(PT_REGS_COUNT != sizeof(struct user_pt_regs) / sizeof(unsigned long));
/*
* PT_DSCR isn't a real reg, but it's important that it doesn't overlap the
* real registers.
*/
BUILD_BUG_ON(PT_DSCR < sizeof(struct user_pt_regs) / sizeof(unsigned long));
}
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