// SPDX-License-Identifier: GPL-2.0
/* ptrace.c */
/* By Ross Biro 1/23/92 */
/* edited by Linus Torvalds */
/* mangled further by Bob Manson ([email protected]) */
/* more mutilation by David Mosberger ([email protected]) */
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/sched/task_stack.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/signal.h>
#include <linux/audit.h>
#include <linux/uaccess.h>
#include <asm/fpu.h>
#include "proto.h"
#define DEBUG DBG_MEM
#undef DEBUG
#ifdef DEBUG
enum {
DBG_MEM = (1<<0),
DBG_BPT = (1<<1),
DBG_MEM_ALL = (1<<2)
};
#define DBG(fac,args) {if ((fac) & DEBUG) printk args;}
#else
#define DBG(fac,args)
#endif
#define BREAKINST 0x00000080 /* call_pal bpt */
/*
* does not yet catch signals sent when the child dies.
* in exit.c or in signal.c.
*/
/*
* Processes always block with the following stack-layout:
*
* +================================+ <---- task + 2*PAGE_SIZE
* | PALcode saved frame (ps, pc, | ^
* | gp, a0, a1, a2) | |
* +================================+ | struct pt_regs
* | | |
* | frame generated by SAVE_ALL | |
* | | v
* +================================+
* | | ^
* | frame saved by do_switch_stack | | struct switch_stack
* | | v
* +================================+
*/
/*
* The following table maps a register index into the stack offset at
* which the register is saved. Register indices are 0-31 for integer
* regs, 32-63 for fp regs, and 64 for the pc. Notice that sp and
* zero have no stack-slot and need to be treated specially (see
* get_reg/put_reg below).
*/
enum {
REG_R0 = 0, REG_F0 = 32, REG_FPCR = 63, REG_PC = 64
};
#define PT_REG(reg) \
(PAGE_SIZE*2 - sizeof(struct pt_regs) + offsetof(struct pt_regs, reg))
#define SW_REG(reg) \
(PAGE_SIZE*2 - sizeof(struct pt_regs) - sizeof(struct switch_stack) \
+ offsetof(struct switch_stack, reg))
#define FP_REG(reg) (offsetof(struct thread_info, reg))
static int regoff[] = {
PT_REG( r0), PT_REG( r1), PT_REG( r2), PT_REG( r3),
PT_REG( r4), PT_REG( r5), PT_REG( r6), PT_REG( r7),
PT_REG( r8), SW_REG( r9), SW_REG( r10), SW_REG( r11),
SW_REG( r12), SW_REG( r13), SW_REG( r14), SW_REG( r15),
PT_REG( r16), PT_REG( r17), PT_REG( r18), PT_REG( r19),
PT_REG( r20), PT_REG( r21), PT_REG( r22), PT_REG( r23),
PT_REG( r24), PT_REG( r25), PT_REG( r26), PT_REG( r27),
PT_REG( r28), PT_REG( gp), -1, -1,
FP_REG(fp[ 0]), FP_REG(fp[ 1]), FP_REG(fp[ 2]), FP_REG(fp[ 3]),
FP_REG(fp[ 4]), FP_REG(fp[ 5]), FP_REG(fp[ 6]), FP_REG(fp[ 7]),
FP_REG(fp[ 8]), FP_REG(fp[ 9]), FP_REG(fp[10]), FP_REG(fp[11]),
FP_REG(fp[12]), FP_REG(fp[13]), FP_REG(fp[14]), FP_REG(fp[15]),
FP_REG(fp[16]), FP_REG(fp[17]), FP_REG(fp[18]), FP_REG(fp[19]),
FP_REG(fp[20]), FP_REG(fp[21]), FP_REG(fp[22]), FP_REG(fp[23]),
FP_REG(fp[24]), FP_REG(fp[25]), FP_REG(fp[26]), FP_REG(fp[27]),
FP_REG(fp[28]), FP_REG(fp[29]), FP_REG(fp[30]), FP_REG(fp[31]),
PT_REG( pc)
};
static unsigned long zero;
/*
* Get address of register REGNO in task TASK.
*/
static unsigned long *
get_reg_addr(struct task_struct * task, unsigned long regno)
{
unsigned long *addr;
if (regno == 30) {
addr = &task_thread_info(task)->pcb.usp;
} else if (regno == 65) {
addr = &task_thread_info(task)->pcb.unique;
} else if (regno == 31 || regno > 65) {
zero = 0;
addr = &zero;
} else {
addr = task_stack_page(task) + regoff[regno];
}
return addr;
}
/*
* Get contents of register REGNO in task TASK.
*/
static unsigned long
get_reg(struct task_struct * task, unsigned long regno)
{
/* Special hack for fpcr -- combine hardware and software bits. */
if (regno == 63) {
unsigned long fpcr = *get_reg_addr(task, regno);
unsigned long swcr
= task_thread_info(task)->ieee_state & IEEE_SW_MASK;
swcr = swcr_update_status(swcr, fpcr);
return fpcr | swcr;
}
return *get_reg_addr(task, regno);
}
/*
* Write contents of register REGNO in task TASK.
*/
static int
put_reg(struct task_struct *task, unsigned long regno, unsigned long data)
{
if (regno == 63) {
task_thread_info(task)->ieee_state
= ((task_thread_info(task)->ieee_state & ~IEEE_SW_MASK)
| (data & IEEE_SW_MASK));
data = (data & FPCR_DYN_MASK) | ieee_swcr_to_fpcr(data);
}
*get_reg_addr(task, regno) = data;
return 0;
}
static inline int
read_int(struct task_struct *task, unsigned long addr, int * data)
{
int copied = access_process_vm(task, addr, data, sizeof(int),
FOLL_FORCE);
return (copied == sizeof(int)) ? 0 : -EIO;
}
static inline int
write_int(struct task_struct *task, unsigned long addr, int data)
{
int copied = access_process_vm(task, addr, &data, sizeof(int),
FOLL_FORCE | FOLL_WRITE);
return (copied == sizeof(int)) ? 0 : -EIO;
}
/*
* Set breakpoint.
*/
int
ptrace_set_bpt(struct task_struct * child)
{
int displ, i, res, reg_b, nsaved = 0;
unsigned int insn, op_code;
unsigned long pc;
pc = get_reg(child, REG_PC);
res = read_int(child, pc, (int *) &insn);
if (res < 0)
return res;
op_code = insn >> 26;
if (op_code >= 0x30) {
/*
* It's a branch: instead of trying to figure out
* whether the branch will be taken or not, we'll put
* a breakpoint at either location. This is simpler,
* more reliable, and probably not a whole lot slower
* than the alternative approach of emulating the
* branch (emulation can be tricky for fp branches).
*/
displ = ((s32)(insn << 11)) >> 9;
task_thread_info(child)->bpt_addr[nsaved++] = pc + 4;
if (displ) /* guard against unoptimized code */
task_thread_info(child)->bpt_addr[nsaved++]
= pc + 4 + displ;
DBG(DBG_BPT, ("execing branch\n"));
} else if (op_code == 0x1a) {
reg_b = (insn >> 16) & 0x1f;
task_thread_info(child)->bpt_addr[nsaved++] = get_reg(child, reg_b);
DBG(DBG_BPT, ("execing jump\n"));
} else {
task_thread_info(child)->bpt_addr[nsaved++] = pc + 4;
DBG(DBG_BPT, ("execing normal insn\n"));
}
/* install breakpoints: */
for (i = 0; i < nsaved; ++i) {
res = read_int(child, task_thread_info(child)->bpt_addr[i],
(int *) &insn);
if (res < 0)
return res;
task_thread_info(child)->bpt_insn[i] = insn;
DBG(DBG_BPT, (" -> next_pc=%lx\n",
task_thread_info(child)->bpt_addr[i]));
res = write_int(child, task_thread_info(child)->bpt_addr[i],
BREAKINST);
if (res < 0)
return res;
}
task_thread_info(child)->bpt_nsaved = nsaved;
return 0;
}
/*
* Ensure no single-step breakpoint is pending. Returns non-zero
* value if child was being single-stepped.
*/
int
ptrace_cancel_bpt(struct task_struct * child)
{
int i, nsaved = task_thread_info(child)->bpt_nsaved;
task_thread_info(child)->bpt_nsaved = 0;
if (nsaved > 2) {
printk("ptrace_cancel_bpt: bogus nsaved: %d!\n", nsaved);
nsaved = 2;
}
for (i = 0; i < nsaved; ++i) {
write_int(child, task_thread_info(child)->bpt_addr[i],
task_thread_info(child)->bpt_insn[i]);
}
return (nsaved != 0);
}
void user_enable_single_step(struct task_struct *child)
{
/* Mark single stepping. */
task_thread_info(child)->bpt_nsaved = -1;
}
void user_disable_single_step(struct task_struct *child)
{
ptrace_cancel_bpt(child);
}
/*
* 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);
}
long arch_ptrace(struct task_struct *child, long request,
unsigned long addr, unsigned long data)
{
unsigned long tmp;
size_t copied;
long ret;
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:
copied = ptrace_access_vm(child, addr, &tmp, sizeof(tmp),
FOLL_FORCE);
ret = -EIO;
if (copied != sizeof(tmp))
break;
force_successful_syscall_return();
ret = tmp;
break;
/* Read register number ADDR. */
case PTRACE_PEEKUSR:
force_successful_syscall_return();
ret = get_reg(child, addr);
DBG(DBG_MEM, ("peek $%lu->%#lx\n", addr, ret));
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 specified register */
DBG(DBG_MEM, ("poke $%lu<-%#lx\n", addr, data));
ret = put_reg(child, addr, data);
break;
default:
ret = ptrace_request(child, request, addr, data);
break;
}
return ret;
}
asmlinkage unsigned long syscall_trace_enter(void)
{
unsigned long ret = 0;
struct pt_regs *regs = current_pt_regs();
if (test_thread_flag(TIF_SYSCALL_TRACE) &&
ptrace_report_syscall_entry(current_pt_regs()))
ret = -1UL;
audit_syscall_entry(regs->r0, regs->r16, regs->r17, regs->r18, regs->r19);
return ret ?: current_pt_regs()->r0;
}
asmlinkage void
syscall_trace_leave(void)
{
audit_syscall_exit(current_pt_regs());
if (test_thread_flag(TIF_SYSCALL_TRACE))
ptrace_report_syscall_exit(current_pt_regs(), 0);
}
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