Commit 8858ac8e authored by Sven Schnelle's avatar Sven Schnelle Committed by Helge Deller

parisc: Implement kprobes

Implement kprobes support for PA-RISC.
Signed-off-by: default avatarSven Schnelle <svens@stackframe.org>
Signed-off-by: default avatarHelge Deller <deller@gmx.de>
parent ea1afe33
...@@ -55,6 +55,7 @@ config PARISC ...@@ -55,6 +55,7 @@ config PARISC
select NEED_DMA_MAP_STATE select NEED_DMA_MAP_STATE
select NEED_SG_DMA_LENGTH select NEED_SG_DMA_LENGTH
select HAVE_ARCH_KGDB select HAVE_ARCH_KGDB
select HAVE_KPROBES
help help
The PA-RISC microprocessor is designed by Hewlett-Packard and used The PA-RISC microprocessor is designed by Hewlett-Packard and used
......
/* SPDX-License-Identifier: GPL-2.0 */
/*
* arch/parisc/include/asm/kprobes.h
*
* PA-RISC kprobes implementation
*
* Copyright (c) 2019 Sven Schnelle <svens@stackframe.org>
*/
#ifndef _PARISC_KPROBES_H
#define _PARISC_KPROBES_H
#ifdef CONFIG_KPROBES
#include <asm-generic/kprobes.h>
#include <linux/types.h>
#include <linux/ptrace.h>
#include <linux/notifier.h>
#define PARISC_KPROBES_BREAK_INSN 0x3ff801f
#define __ARCH_WANT_KPROBES_INSN_SLOT
#define MAX_INSN_SIZE 1
typedef u32 kprobe_opcode_t;
struct kprobe;
void arch_remove_kprobe(struct kprobe *p);
#define flush_insn_slot(p) \
flush_icache_range((unsigned long)&(p)->ainsn.insn[0], \
(unsigned long)&(p)->ainsn.insn[0] + \
sizeof(kprobe_opcode_t))
#define kretprobe_blacklist_size 0
struct arch_specific_insn {
kprobe_opcode_t *insn;
};
struct prev_kprobe {
struct kprobe *kp;
unsigned long status;
};
struct kprobe_ctlblk {
unsigned int kprobe_status;
struct prev_kprobe prev_kprobe;
unsigned long iaoq[2];
};
int __kprobes parisc_kprobe_break_handler(struct pt_regs *regs);
int __kprobes parisc_kprobe_ss_handler(struct pt_regs *regs);
#endif /* CONFIG_KPROBES */
#endif /* _PARISC_KPROBES_H */
...@@ -34,3 +34,4 @@ obj-$(CONFIG_PARISC_CPU_TOPOLOGY) += topology.o ...@@ -34,3 +34,4 @@ obj-$(CONFIG_PARISC_CPU_TOPOLOGY) += topology.o
obj-$(CONFIG_FUNCTION_TRACER) += ftrace.o obj-$(CONFIG_FUNCTION_TRACER) += ftrace.o
obj-$(CONFIG_FUNCTION_GRAPH_TRACER) += ftrace.o obj-$(CONFIG_FUNCTION_GRAPH_TRACER) += ftrace.o
obj-$(CONFIG_KGDB) += kgdb.o obj-$(CONFIG_KGDB) += kgdb.o
obj-$(CONFIG_KPROBES) += kprobes.o
// SPDX-License-Identifier: GPL-2.0
/*
* arch/parisc/kernel/kprobes.c
*
* PA-RISC kprobes implementation
*
* Copyright (c) 2019 Sven Schnelle <svens@stackframe.org>
*/
#include <linux/types.h>
#include <linux/kprobes.h>
#include <linux/slab.h>
#include <asm/cacheflush.h>
#include <asm/patch.h>
DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;
DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
int __kprobes arch_prepare_kprobe(struct kprobe *p)
{
if ((unsigned long)p->addr & 3UL)
return -EINVAL;
p->ainsn.insn = get_insn_slot();
if (!p->ainsn.insn)
return -ENOMEM;
memcpy(p->ainsn.insn, p->addr,
MAX_INSN_SIZE * sizeof(kprobe_opcode_t));
p->opcode = *p->addr;
flush_insn_slot(p);
return 0;
}
void __kprobes arch_remove_kprobe(struct kprobe *p)
{
if (!p->ainsn.insn)
return;
free_insn_slot(p->ainsn.insn, 0);
p->ainsn.insn = NULL;
}
void __kprobes arch_arm_kprobe(struct kprobe *p)
{
patch_text(p->addr, PARISC_KPROBES_BREAK_INSN);
}
void __kprobes arch_disarm_kprobe(struct kprobe *p)
{
patch_text(p->addr, p->opcode);
}
static void __kprobes save_previous_kprobe(struct kprobe_ctlblk *kcb)
{
kcb->prev_kprobe.kp = kprobe_running();
kcb->prev_kprobe.status = kcb->kprobe_status;
}
static void __kprobes restore_previous_kprobe(struct kprobe_ctlblk *kcb)
{
__this_cpu_write(current_kprobe, kcb->prev_kprobe.kp);
kcb->kprobe_status = kcb->prev_kprobe.status;
}
static inline void __kprobes set_current_kprobe(struct kprobe *p)
{
__this_cpu_write(current_kprobe, p);
}
static void __kprobes setup_singlestep(struct kprobe *p,
struct kprobe_ctlblk *kcb, struct pt_regs *regs)
{
kcb->iaoq[0] = regs->iaoq[0];
kcb->iaoq[1] = regs->iaoq[1];
regs->iaoq[0] = (unsigned long)p->ainsn.insn;
mtctl(0, 0);
regs->gr[0] |= PSW_R;
}
int __kprobes parisc_kprobe_break_handler(struct pt_regs *regs)
{
struct kprobe *p;
struct kprobe_ctlblk *kcb;
preempt_disable();
kcb = get_kprobe_ctlblk();
p = get_kprobe((unsigned long *)regs->iaoq[0]);
if (!p) {
preempt_enable_no_resched();
return 0;
}
if (kprobe_running()) {
/*
* We have reentered the kprobe_handler, since another kprobe
* was hit while within the handler, we save the original
* kprobes and single step on the instruction of the new probe
* without calling any user handlers to avoid recursive
* kprobes.
*/
save_previous_kprobe(kcb);
set_current_kprobe(p);
kprobes_inc_nmissed_count(p);
setup_singlestep(p, kcb, regs);
kcb->kprobe_status = KPROBE_REENTER;
return 1;
}
set_current_kprobe(p);
kcb->kprobe_status = KPROBE_HIT_ACTIVE;
/* If we have no pre-handler or it returned 0, we continue with
* normal processing. If we have a pre-handler and it returned
* non-zero - which means user handler setup registers to exit
* to another instruction, we must skip the single stepping.
*/
if (!p->pre_handler || !p->pre_handler(p, regs)) {
setup_singlestep(p, kcb, regs);
kcb->kprobe_status = KPROBE_HIT_SS;
} else {
reset_current_kprobe();
preempt_enable_no_resched();
}
return 1;
}
int __kprobes parisc_kprobe_ss_handler(struct pt_regs *regs)
{
struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
struct kprobe *p = kprobe_running();
if (regs->iaoq[0] != (unsigned long)p->ainsn.insn+4)
return 0;
/* restore back original saved kprobe variables and continue */
if (kcb->kprobe_status == KPROBE_REENTER) {
restore_previous_kprobe(kcb);
return 1;
}
/* for absolute branch instructions we can copy iaoq_b. for relative
* branch instructions we need to calculate the new address based on the
* difference between iaoq_f and iaoq_b. We cannot use iaoq_b without
* modificationt because it's based on our ainsn.insn address.
*/
if (p->post_handler)
p->post_handler(p, regs, 0);
switch (regs->iir >> 26) {
case 0x38: /* BE */
case 0x39: /* BE,L */
case 0x3a: /* BV */
case 0x3b: /* BVE */
/* for absolute branches, regs->iaoq[1] has already the right
* address
*/
regs->iaoq[0] = kcb->iaoq[1];
break;
default:
regs->iaoq[1] = kcb->iaoq[0];
regs->iaoq[1] += (regs->iaoq[1] - regs->iaoq[0]) + 4;
regs->iaoq[0] = kcb->iaoq[1];
break;
}
kcb->kprobe_status = KPROBE_HIT_SSDONE;
reset_current_kprobe();
return 1;
}
bool arch_kprobe_on_func_entry(unsigned long offset)
{
return !offset;
}
int __init arch_init_kprobes(void)
{
return 0;
}
...@@ -43,6 +43,7 @@ ...@@ -43,6 +43,7 @@
#include <asm/tlbflush.h> #include <asm/tlbflush.h>
#include <asm/cacheflush.h> #include <asm/cacheflush.h>
#include <linux/kgdb.h> #include <linux/kgdb.h>
#include <linux/kprobes.h>
#include "../math-emu/math-emu.h" /* for handle_fpe() */ #include "../math-emu/math-emu.h" /* for handle_fpe() */
...@@ -294,6 +295,14 @@ static void handle_break(struct pt_regs *regs) ...@@ -294,6 +295,14 @@ static void handle_break(struct pt_regs *regs)
(tt == BUG_TRAP_TYPE_NONE) ? 9 : 0); (tt == BUG_TRAP_TYPE_NONE) ? 9 : 0);
} }
#ifdef CONFIG_KPROBES
if (unlikely(iir == PARISC_KPROBES_BREAK_INSN)) {
parisc_kprobe_break_handler(regs);
return;
}
#endif
#ifdef CONFIG_KGDB #ifdef CONFIG_KGDB
if (unlikely(iir == PARISC_KGDB_COMPILED_BREAK_INSN || if (unlikely(iir == PARISC_KGDB_COMPILED_BREAK_INSN ||
iir == PARISC_KGDB_BREAK_INSN)) { iir == PARISC_KGDB_BREAK_INSN)) {
...@@ -528,6 +537,11 @@ void notrace handle_interruption(int code, struct pt_regs *regs) ...@@ -528,6 +537,11 @@ void notrace handle_interruption(int code, struct pt_regs *regs)
/* Recovery counter trap */ /* Recovery counter trap */
regs->gr[0] &= ~PSW_R; regs->gr[0] &= ~PSW_R;
#ifdef CONFIG_KPROBES
if (parisc_kprobe_ss_handler(regs))
return;
#endif
#ifdef CONFIG_KGDB #ifdef CONFIG_KGDB
if (kgdb_single_step) { if (kgdb_single_step) {
kgdb_handle_exception(0, SIGTRAP, 0, regs); kgdb_handle_exception(0, SIGTRAP, 0, regs);
......
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