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-too.c (2077B)

      1// SPDX-License-Identifier: GPL-2.0-only
      2#include <linux/module.h>
      3
      4#include <linux/mm.h> /* for handle_mm_fault() */
      5#include <linux/ftrace.h>
      6#include <asm/asm-offsets.h>
      7
      8extern void my_direct_func(struct vm_area_struct *vma,
      9			   unsigned long address, unsigned int flags);
     10
     11void my_direct_func(struct vm_area_struct *vma,
     12			unsigned long address, unsigned int flags)
     13{
     14	trace_printk("handle mm fault vma=%p address=%lx flags=%x\n",
     15		     vma, address, flags);
     16}
     17
     18extern void my_tramp(void *);
     19
     20#ifdef CONFIG_X86_64
     21
     22#include <asm/ibt.h>
     23
     24asm (
     25"	.pushsection    .text, \"ax\", @progbits\n"
     26"	.type		my_tramp, @function\n"
     27"	.globl		my_tramp\n"
     28"   my_tramp:"
     29	ASM_ENDBR
     30"	pushq %rbp\n"
     31"	movq %rsp, %rbp\n"
     32"	pushq %rdi\n"
     33"	pushq %rsi\n"
     34"	pushq %rdx\n"
     35"	call my_direct_func\n"
     36"	popq %rdx\n"
     37"	popq %rsi\n"
     38"	popq %rdi\n"
     39"	leave\n"
     40	ASM_RET
     41"	.size		my_tramp, .-my_tramp\n"
     42"	.popsection\n"
     43);
     44
     45#endif /* CONFIG_X86_64 */
     46
     47#ifdef CONFIG_S390
     48
     49asm (
     50"	.pushsection	.text, \"ax\", @progbits\n"
     51"	.type		my_tramp, @function\n"
     52"	.globl		my_tramp\n"
     53"   my_tramp:"
     54"	lgr		%r1,%r15\n"
     55"	stmg		%r0,%r5,"__stringify(__SF_GPRS)"(%r15)\n"
     56"	stg		%r14,"__stringify(__SF_GPRS+8*8)"(%r15)\n"
     57"	aghi		%r15,"__stringify(-STACK_FRAME_OVERHEAD)"\n"
     58"	stg		%r1,"__stringify(__SF_BACKCHAIN)"(%r15)\n"
     59"	brasl		%r14,my_direct_func\n"
     60"	aghi		%r15,"__stringify(STACK_FRAME_OVERHEAD)"\n"
     61"	lmg		%r0,%r5,"__stringify(__SF_GPRS)"(%r15)\n"
     62"	lg		%r14,"__stringify(__SF_GPRS+8*8)"(%r15)\n"
     63"	lgr		%r1,%r0\n"
     64"	br		%r1\n"
     65"	.size		my_tramp, .-my_tramp\n"
     66"	.popsection\n"
     67);
     68
     69#endif /* CONFIG_S390 */
     70
     71static int __init ftrace_direct_init(void)
     72{
     73	return register_ftrace_direct((unsigned long)handle_mm_fault,
     74				     (unsigned long)my_tramp);
     75}
     76
     77static void __exit ftrace_direct_exit(void)
     78{
     79	unregister_ftrace_direct((unsigned long)handle_mm_fault,
     80				 (unsigned long)my_tramp);
     81}
     82
     83module_init(ftrace_direct_init);
     84module_exit(ftrace_direct_exit);
     85
     86MODULE_AUTHOR("Steven Rostedt");
     87MODULE_DESCRIPTION("Another example use case of using register_ftrace_direct()");
     88MODULE_LICENSE("GPL");