cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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ftrace.c (3059B)

      1// SPDX-License-Identifier: GPL-2.0
      2#include <linux/spinlock.h>
      3#include <linux/hardirq.h>
      4#include <linux/ftrace.h>
      5#include <linux/percpu.h>
      6#include <linux/init.h>
      7#include <linux/list.h>
      8#include <trace/syscall.h>
      9
     10#include <asm/ftrace.h>
     11
     12#ifdef CONFIG_DYNAMIC_FTRACE
     13static const u32 ftrace_nop = 0x01000000;
     14
     15static u32 ftrace_call_replace(unsigned long ip, unsigned long addr)
     16{
     17	u32 call;
     18	s32 off;
     19
     20	off = ((s32)addr - (s32)ip);
     21	call = 0x40000000 | ((u32)off >> 2);
     22
     23	return call;
     24}
     25
     26static int ftrace_modify_code(unsigned long ip, u32 old, u32 new)
     27{
     28	u32 replaced;
     29	int faulted;
     30
     31	__asm__ __volatile__(
     32	"1:	cas	[%[ip]], %[old], %[new]\n"
     33	"	flush	%[ip]\n"
     34	"	mov	0, %[faulted]\n"
     35	"2:\n"
     36	"	.section .fixup,#alloc,#execinstr\n"
     37	"	.align	4\n"
     38	"3:	sethi	%%hi(2b), %[faulted]\n"
     39	"	jmpl	%[faulted] + %%lo(2b), %%g0\n"
     40	"	 mov	1, %[faulted]\n"
     41	"	.previous\n"
     42	"	.section __ex_table,\"a\"\n"
     43	"	.align	4\n"
     44	"	.word	1b, 3b\n"
     45	"	.previous\n"
     46	: "=r" (replaced), [faulted] "=r" (faulted)
     47	: [new] "0" (new), [old] "r" (old), [ip] "r" (ip)
     48	: "memory");
     49
     50	if (replaced != old && replaced != new)
     51		faulted = 2;
     52
     53	return faulted;
     54}
     55
     56int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec, unsigned long addr)
     57{
     58	unsigned long ip = rec->ip;
     59	u32 old, new;
     60
     61	old = ftrace_call_replace(ip, addr);
     62	new = ftrace_nop;
     63	return ftrace_modify_code(ip, old, new);
     64}
     65
     66int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
     67{
     68	unsigned long ip = rec->ip;
     69	u32 old, new;
     70
     71	old = ftrace_nop;
     72	new = ftrace_call_replace(ip, addr);
     73	return ftrace_modify_code(ip, old, new);
     74}
     75
     76int ftrace_update_ftrace_func(ftrace_func_t func)
     77{
     78	unsigned long ip = (unsigned long)(&ftrace_call);
     79	u32 old, new;
     80
     81	old = *(u32 *) &ftrace_call;
     82	new = ftrace_call_replace(ip, (unsigned long)func);
     83	return ftrace_modify_code(ip, old, new);
     84}
     85#endif
     86
     87#ifdef CONFIG_FUNCTION_GRAPH_TRACER
     88
     89#ifdef CONFIG_DYNAMIC_FTRACE
     90extern void ftrace_graph_call(void);
     91
     92int ftrace_enable_ftrace_graph_caller(void)
     93{
     94	unsigned long ip = (unsigned long)(&ftrace_graph_call);
     95	u32 old, new;
     96
     97	old = *(u32 *) &ftrace_graph_call;
     98	new = ftrace_call_replace(ip, (unsigned long) &ftrace_graph_caller);
     99	return ftrace_modify_code(ip, old, new);
    100}
    101
    102int ftrace_disable_ftrace_graph_caller(void)
    103{
    104	unsigned long ip = (unsigned long)(&ftrace_graph_call);
    105	u32 old, new;
    106
    107	old = *(u32 *) &ftrace_graph_call;
    108	new = ftrace_call_replace(ip, (unsigned long) &ftrace_stub);
    109
    110	return ftrace_modify_code(ip, old, new);
    111}
    112
    113#endif /* !CONFIG_DYNAMIC_FTRACE */
    114
    115/*
    116 * Hook the return address and push it in the stack of return addrs
    117 * in current thread info.
    118 */
    119unsigned long prepare_ftrace_return(unsigned long parent,
    120				    unsigned long self_addr,
    121				    unsigned long frame_pointer)
    122{
    123	unsigned long return_hooker = (unsigned long) &return_to_handler;
    124
    125	if (unlikely(atomic_read(&current->tracing_graph_pause)))
    126		return parent + 8UL;
    127
    128	if (function_graph_enter(parent, self_addr, frame_pointer, NULL))
    129		return parent + 8UL;
    130
    131	return return_hooker;
    132}
    133#endif /* CONFIG_FUNCTION_GRAPH_TRACER */