Hello Linus,
On 02/03/2021 09:29, Linus Walleij wrote:
>>>> FTRACE's function tracer currently doesn't always work on ARM with
>>>> MODULE_PLT option enabled. If the module is loaded too far, FTRACE's
First of all:
config ARM_MODULE_PLTS
bool "Use PLTs to allow module memory to spill over into vmalloc area"
[...]
> Any suggestions on a quick use case that illustrates how the problem
> manifest and how to test it is gone? The errors in patch 2, what do
> I need to configure in to get them? Does it manifest at modprobe?
And then I use this module to test for the problem:
/**********************************************************************
* Author: Alexander Sverdlin <alexander.sverd...@nokia.com>
*
* Copyright (c) 2018 Nokia
*
* SPDX-License-Identifier: GPL-2.0
*
* This module is intended to test ARM MODULE_PLT functionality
**********************************************************************/
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/module.h>
static int fatmod_init(void)
{
asm volatile (".rept (6 * 1024 * 1024 / 2)\n\t"
"nop\n\t"
".endr");
return 0;
}
module_init(fatmod_init);
static void __exit fatmod_exit(void)
{
}
module_exit(fatmod_exit);
MODULE_AUTHOR("Alexander Sverdlin <alexander.sverd...@nokia.com>");
MODULE_DESCRIPTION("ARM MODULE_PLT test module");
MODULE_LICENSE("GPL");
--
Best regards,
Alexander Sverdlin.
