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-direct.c (1866B)

      1// SPDX-License-Identifier: GPL-2.0-only
      2#include <linux/module.h>
      3
      4#include <linux/sched.h> /* for wake_up_process() */
      5#include <linux/ftrace.h>
      6#include <asm/asm-offsets.h>
      7
      8extern void my_direct_func(struct task_struct *p);
      9
     10void my_direct_func(struct task_struct *p)
     11{
     12	trace_printk("waking up %s-%d\n", p->comm, p->pid);
     13}
     14
     15extern void my_tramp(void *);
     16
     17#ifdef CONFIG_X86_64
     18
     19#include <asm/ibt.h>
     20
     21asm (
     22"	.pushsection    .text, \"ax\", @progbits\n"
     23"	.type		my_tramp, @function\n"
     24"	.globl		my_tramp\n"
     25"   my_tramp:"
     26	ASM_ENDBR
     27"	pushq %rbp\n"
     28"	movq %rsp, %rbp\n"
     29"	pushq %rdi\n"
     30"	call my_direct_func\n"
     31"	popq %rdi\n"
     32"	leave\n"
     33	ASM_RET
     34"	.size		my_tramp, .-my_tramp\n"
     35"	.popsection\n"
     36);
     37
     38#endif /* CONFIG_X86_64 */
     39
     40#ifdef CONFIG_S390
     41
     42asm (
     43"	.pushsection	.text, \"ax\", @progbits\n"
     44"	.type		my_tramp, @function\n"
     45"	.globl		my_tramp\n"
     46"   my_tramp:"
     47"	lgr		%r1,%r15\n"
     48"	stmg		%r0,%r5,"__stringify(__SF_GPRS)"(%r15)\n"
     49"	stg		%r14,"__stringify(__SF_GPRS+8*8)"(%r15)\n"
     50"	aghi		%r15,"__stringify(-STACK_FRAME_OVERHEAD)"\n"
     51"	stg		%r1,"__stringify(__SF_BACKCHAIN)"(%r15)\n"
     52"	brasl		%r14,my_direct_func\n"
     53"	aghi		%r15,"__stringify(STACK_FRAME_OVERHEAD)"\n"
     54"	lmg		%r0,%r5,"__stringify(__SF_GPRS)"(%r15)\n"
     55"	lg		%r14,"__stringify(__SF_GPRS+8*8)"(%r15)\n"
     56"	lgr		%r1,%r0\n"
     57"	br		%r1\n"
     58"	.size		my_tramp, .-my_tramp\n"
     59"	.popsection\n"
     60);
     61
     62#endif /* CONFIG_S390 */
     63
     64static int __init ftrace_direct_init(void)
     65{
     66	return register_ftrace_direct((unsigned long)wake_up_process,
     67				     (unsigned long)my_tramp);
     68}
     69
     70static void __exit ftrace_direct_exit(void)
     71{
     72	unregister_ftrace_direct((unsigned long)wake_up_process,
     73				 (unsigned long)my_tramp);
     74}
     75
     76module_init(ftrace_direct_init);
     77module_exit(ftrace_direct_exit);
     78
     79MODULE_AUTHOR("Steven Rostedt");
     80MODULE_DESCRIPTION("Example use case of using register_ftrace_direct()");
     81MODULE_LICENSE("GPL");