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// SPDX-License-Identifier: GPL-2.0
/*
* Code for tracing calls in Linux kernel.
* Copyright (C) 2009-2016 Helge Deller <deller@gmx.de>
*
* based on code for x86 which is:
* Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
*
* future possible enhancements:
* - add CONFIG_STACK_TRACER
*/
#include <linux/init.h>
#include <linux/ftrace.h>
#include <linux/uaccess.h>
#include <linux/kprobes.h>
#include <linux/ptrace.h>
#include <asm/assembly.h>
#include <asm/sections.h>
#include <asm/ftrace.h>
#include <asm/patch.h>
#define __hot __section(".text.hot")
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
/*
* Hook the return address and push it in the stack of return addrs
* in current thread info.
*/
static void __hot prepare_ftrace_return(unsigned long *parent,
unsigned long self_addr)
{
unsigned long old;
extern int parisc_return_to_handler;
if (unlikely(ftrace_graph_is_dead()))
return;
if (unlikely(atomic_read(¤t->tracing_graph_pause)))
return;
old = *parent;
if (!function_graph_enter(old, self_addr, 0, NULL))
/* activate parisc_return_to_handler() as return point */
*parent = (unsigned long) &parisc_return_to_handler;
}
#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
void notrace __hot ftrace_function_trampoline(unsigned long parent,
unsigned long self_addr,
unsigned long org_sp_gr3,
struct pt_regs *regs)
{
#ifndef CONFIG_DYNAMIC_FTRACE
extern ftrace_func_t ftrace_trace_function;
#endif
extern struct ftrace_ops *function_trace_op;
if (function_trace_op->flags & FTRACE_OPS_FL_ENABLED &&
ftrace_trace_function != ftrace_stub)
ftrace_trace_function(self_addr, parent,
function_trace_op, regs);
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
if (dereference_function_descriptor(ftrace_graph_return) !=
dereference_function_descriptor(ftrace_stub) ||
ftrace_graph_entry != ftrace_graph_entry_stub) {
unsigned long *parent_rp;
/* calculate pointer to %rp in stack */
parent_rp = (unsigned long *) (org_sp_gr3 - RP_OFFSET);
/* sanity check: parent_rp should hold parent */
if (*parent_rp != parent)
return;
prepare_ftrace_return(parent_rp, self_addr);
return;
}
#endif
}
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
int ftrace_enable_ftrace_graph_caller(void)
{
return 0;
}
int ftrace_disable_ftrace_graph_caller(void)
{
return 0;
}
#endif
#ifdef CONFIG_DYNAMIC_FTRACE
int __init ftrace_dyn_arch_init(void)
{
return 0;
}
int ftrace_update_ftrace_func(ftrace_func_t func)
{
return 0;
}
int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
unsigned long addr)
{
return 0;
}
unsigned long ftrace_call_adjust(unsigned long addr)
{
return addr+(FTRACE_PATCHABLE_FUNCTION_SIZE-1)*4;
}
int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
{
u32 insn[FTRACE_PATCHABLE_FUNCTION_SIZE];
u32 *tramp;
int size, ret, i;
void *ip;
#ifdef CONFIG_64BIT
unsigned long addr2 =
(unsigned long)dereference_function_descriptor((void *)addr);
u32 ftrace_trampoline[] = {
0x73c10208, /* std,ma r1,100(sp) */
0x0c2110c1, /* ldd -10(r1),r1 */
0xe820d002, /* bve,n (r1) */
addr2 >> 32,
addr2 & 0xffffffff,
0xe83f1fd7, /* b,l,n .-14,r1 */
};
u32 ftrace_trampoline_unaligned[] = {
addr2 >> 32,
addr2 & 0xffffffff,
0x37de0200, /* ldo 100(sp),sp */
0x73c13e01, /* std r1,-100(sp) */
0x34213ff9, /* ldo -4(r1),r1 */
0x50213fc1, /* ldd -20(r1),r1 */
0xe820d002, /* bve,n (r1) */
0xe83f1fcf, /* b,l,n .-20,r1 */
};
BUILD_BUG_ON(ARRAY_SIZE(ftrace_trampoline_unaligned) >
FTRACE_PATCHABLE_FUNCTION_SIZE);
#else
u32 ftrace_trampoline[] = {
(u32)addr,
0x6fc10080, /* stw,ma r1,40(sp) */
0x48213fd1, /* ldw -18(r1),r1 */
0xe820c002, /* bv,n r0(r1) */
0xe83f1fdf, /* b,l,n .-c,r1 */
};
#endif
BUILD_BUG_ON(ARRAY_SIZE(ftrace_trampoline) >
FTRACE_PATCHABLE_FUNCTION_SIZE);
size = sizeof(ftrace_trampoline);
tramp = ftrace_trampoline;
#ifdef CONFIG_64BIT
if (rec->ip & 0x4) {
size = sizeof(ftrace_trampoline_unaligned);
tramp = ftrace_trampoline_unaligned;
}
#endif
ip = (void *)(rec->ip + 4 - size);
ret = copy_from_kernel_nofault(insn, ip, size);
if (ret)
return ret;
for (i = 0; i < size / 4; i++) {
if (insn[i] != INSN_NOP)
return -EINVAL;
}
__patch_text_multiple(ip, tramp, size);
return 0;
}
int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec,
unsigned long addr)
{
u32 insn[FTRACE_PATCHABLE_FUNCTION_SIZE];
int i;
for (i = 0; i < ARRAY_SIZE(insn); i++)
insn[i] = INSN_NOP;
__patch_text((void *)rec->ip, INSN_NOP);
__patch_text_multiple((void *)rec->ip + 4 - sizeof(insn),
insn, sizeof(insn)-4);
return 0;
}
#endif
#ifdef CONFIG_KPROBES_ON_FTRACE
void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip,
struct ftrace_ops *ops, struct pt_regs *regs)
{
struct kprobe_ctlblk *kcb;
struct kprobe *p = get_kprobe((kprobe_opcode_t *)ip);
if (unlikely(!p) || kprobe_disabled(p))
return;
if (kprobe_running()) {
kprobes_inc_nmissed_count(p);
return;
}
__this_cpu_write(current_kprobe, p);
kcb = get_kprobe_ctlblk();
kcb->kprobe_status = KPROBE_HIT_ACTIVE;
regs->iaoq[0] = ip;
regs->iaoq[1] = ip + 4;
if (!p->pre_handler || !p->pre_handler(p, regs)) {
regs->iaoq[0] = ip + 4;
regs->iaoq[1] = ip + 8;
if (unlikely(p->post_handler)) {
kcb->kprobe_status = KPROBE_HIT_SSDONE;
p->post_handler(p, regs, 0);
}
}
__this_cpu_write(current_kprobe, NULL);
}
NOKPROBE_SYMBOL(kprobe_ftrace_handler);
int arch_prepare_kprobe_ftrace(struct kprobe *p)
{
p->ainsn.insn = NULL;
return 0;
}
#endif
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