path: root/arch/ia64/kernel/kprobes.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *  Kernel Probes (KProbes)
 *  arch/ia64/kernel/kprobes.c
 *
 * Copyright (C) IBM Corporation, 2002, 2004
 * Copyright (C) Intel Corporation, 2005
 *
 * 2005-Apr     Rusty Lynch <rusty.lynch@intel.com> and Anil S Keshavamurthy
 *              <anil.s.keshavamurthy@intel.com> adapted from i386
 */

#include <linux/kprobes.h>
#include <linux/ptrace.h>
#include <linux/string.h>
#include <linux/slab.h>
#include <linux/preempt.h>
#include <linux/extable.h>
#include <linux/kdebug.h>
#include <linux/pgtable.h>

#include <asm/sections.h>
#include <asm/exception.h>

DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;
DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);

struct kretprobe_blackpoint kretprobe_blacklist[] = {{NULL, NULL}};

enum instruction_type {A, I, M, F, B, L, X, u};
static enum instruction_type bundle_encoding[32][3] = {
	[0x00] = { M, I, I },
	[0x01] = { M, I, I },
	[0x02] = { M, I, I },
	[0x03] = { M, I, I },
	[0x04] = { M, L, X },
	[0x05] = { M, L, X },
	[0x06] = { u, u, u },
	[0x07] = { u, u, u },
	[0x08] = { M, M, I },
	[0x09] = { M, M, I },
	[0x0A] = { M, M, I },
	[0x0B] = { M, M, I },
	[0x0C] = { M, F, I },
	[0x0D] = { M, F, I },
	[0x0E] = { M, M, F },
	[0x0F] = { M, M, F },
	[0x10] = { M, I, B },
	[0x11] = { M, I, B },
	[0x12] = { M, B, B },
	[0x13] = { M, B, B },
	[0x14] = { u, u, u },
	[0x15] = { u, u, u },
	[0x16] = { B, B, B },
	[0x17] = { B, B, B },
	[0x18] = { M, M, B },
	[0x19] = { M, M, B },
	[0x1A] = { u, u, u },
	[0x1B] = { u, u, u },
	[0x1C] = { M, F, B },
	[0x1D] = { M, F, B },
	[0x1E] = { u, u, u },
	[0x1F] = { u, u, u },
};

/* Insert a long branch code */
static void __kprobes set_brl_inst(void *from, void *to)
{
	s64 rel = ((s64) to - (s64) from) >> 4;
	bundle_t *brl;
	brl = (bundle_t *) ((u64) from & ~0xf);
	brl->quad0.template = 0x05;	/* [MLX](stop) */
	brl->quad0.slot0 = NOP_M_INST;	/* nop.m 0x0 */
	brl->quad0.slot1_p0 = ((rel >> 20) & 0x7fffffffff) << 2;
	brl->quad1.slot1_p1 = (((rel >> 20) & 0x7fffffffff) << 2) >> (64 - 46);
	/* brl.cond.sptk.many.clr rel<<4 (qp=0) */
	brl->quad1.slot2 = BRL_INST(rel >> 59, rel & 0xfffff);
}

/*
 * In this function we check to see if the instruction
 * is IP relative instruction and update the kprobe
 * inst flag accordingly
 */
static void __kprobes update_kprobe_inst_flag(uint template, uint  slot,
					      uint major_opcode,
					      unsigned long kprobe_inst,
					      struct kprobe *p)
{
	p->ainsn.inst_flag = 0;
	p->ainsn.target_br_reg = 0;
	p->ainsn.slot = slot;

	/* Check for Break instruction
	 * Bits 37:40 Major opcode to be zero
	 * Bits 27:32 X6 to be zero
	 * Bits 32:35 X3 to be zero
	 */
	if ((!major_opcode) && (!((kprobe_inst >> 27) & 0x1FF)) ) {
		/* is a break instruction */
	 	p->ainsn.inst_flag |= INST_FLAG_BREAK_INST;
		return;
	}

	if (bundle_encoding[template][slot] == B) {
		switch (major_opcode) {
		  case INDIRECT_CALL_OPCODE:
	 		p->ainsn.inst_flag |= INST_FLAG_FIX_BRANCH_REG;
			p->ainsn.target_br_reg = ((kprobe_inst >> 6) & 0x7);
			break;
		  case IP_RELATIVE_PREDICT_OPCODE:
		  case IP_RELATIVE_BRANCH_OPCODE:
			p->ainsn.inst_flag |= INST_FLAG_FIX_RELATIVE_IP_ADDR;
			break;
		  case IP_RELATIVE_CALL_OPCODE:
			p->ainsn.inst_flag |= INST_FLAG_FIX_RELATIVE_IP_ADDR;
			p->ainsn.inst_flag |= INST_FLAG_FIX_BRANCH_REG;
			p->ainsn.target_br_reg = ((kprobe_inst >> 6) & 0x7);
			break;
		}
	} else if (bundle_encoding[template][slot] == X) {
		switch (major_opcode) {
		  case LONG_CALL_OPCODE:
			p->ainsn.inst_flag |= INST_FLAG_FIX_BRANCH_REG;
			p->ainsn.target_br_reg = ((kprobe_inst >> 6) & 0x7);
		  break;
		}
	}
	return;
}

/*
 * In this function we check to see if the instruction
 * (qp) cmpx.crel.ctype p1,p2=r2,r3
 * on which we are inserting kprobe is cmp instruction
 * with ctype as unc.
 */
static uint __kprobes is_cmp_ctype_unc_inst(uint template, uint slot,
					    uint major_opcode,
					    unsigned long kprobe_inst)
{
	cmp_inst_t cmp_inst;
	uint ctype_unc = 0;

	if (!((bundle_encoding[template][slot] == I) ||
		(bundle_encoding[template][slot] == M)))
		goto out;

	if (!((major_opcode == 0xC) || (major_opcode == 0xD) ||
		(major_opcode == 0xE)))
		goto out;

	cmp_inst.l = kprobe_inst;
	if ((cmp_inst.f.x2 == 0) || (cmp_inst.f.