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Commit a2b53673 authored by Heiko Carstens's avatar Heiko Carstens Committed by Martin Schwidefsky
Browse files

[S390] kprobes: use probe_kernel_write 



Use proble_kernel_write() to patch the kernel.

Signed-off-by: default avatarHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent 88df125f

arch/s390/kernel/kprobes.c

+2 −29
Original line number Diff line number Diff line
@@ -25,9 +25,9 @@ 
#include <linux/preempt.h>

#include <linux/stop_machine.h>

#include <linux/kdebug.h>

#include <linux/uaccess.h>

#include <asm/cacheflush.h>

#include <asm/sections.h>

#include <asm/uaccess.h>

#include <linux/module.h>



DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;
@@ -155,35 +155,8 @@ void __kprobes get_instruction_type(struct arch_specific_insn *ainsn) 
static int __kprobes swap_instruction(void *aref)

{

	struct ins_replace_args *args = aref;

	u32 *addr;

	u32 instr;

	int err = -EFAULT;



	/*

	 * Text segment is read-only, hence we use stura to bypass dynamic

	 * address translation to exchange the instruction. Since stura

	 * always operates on four bytes, but we only want to exchange two

	 * bytes do some calculations to get things right. In addition we

	 * shall not cross any page boundaries (vmalloc area!) when writing

	 * the new instruction.

	 */

	addr = (u32 *)((unsigned long)args->ptr & -4UL);

	if ((unsigned long)args->ptr & 2)

		instr = ((*addr) & 0xffff0000) | args->new;

	else

		instr = ((*addr) & 0x0000ffff) | args->new << 16;



	asm volatile(

		"	lra	%1,0(%1)\n"

		"0:	stura	%2,%1\n"

		"1:	la	%0,0\n"

		"2:\n"

		EX_TABLE(0b,2b)

		: "+d" (err)

		: "a" (addr), "d" (instr)

		: "memory", "cc");



	return err;

	return probe_kernel_write(args->ptr, &args->new, sizeof(args->new));

}



void __kprobes arch_arm_kprobe(struct kprobe *p)