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SubjectRe: [PATCH v4 2/8] riscv/kprobe: Allocate detour buffer from module area
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在 2022/11/17 9:25, Steven Rostedt 写道:
> On Sun, 6 Nov 2022 18:03:10 +0800
> Chen Guokai <chenguokai17@mails.ucas.ac.cn> wrote:
>
>> @@ -84,6 +85,30 @@ int __kprobes arch_prepare_kprobe(struct kprobe *p)
>> }
>>
>> #ifdef CONFIG_MMU
>> +#if defined(CONFIG_OPTPROBES) && defined(CONFIG_64BIT)
>> +void *alloc_optinsn_page(void)
>> +{
>> + void *page;
>> +
>> + page = __vmalloc_node_range(PAGE_SIZE, 1, MODULES_VADDR,
>> + MODULES_END, GFP_KERNEL,
>> + PAGE_KERNEL, 0, NUMA_NO_NODE,
>> + __builtin_return_address(0));
>> + if (!page)
>> + return NULL;
>> +
>> + set_vm_flush_reset_perms(page);
>> + /*
>> + * First make the page read-only, and only then make it executable to
>> + * prevent it from being W+X in between.
>> + */
>> + set_memory_ro((unsigned long)page, 1);
>> + set_memory_x((unsigned long)page, 1);
>
> FYI, the above combination is going to be going away:
>
> https://lore.kernel.org/all/Y10OyLCLAAS6rsZv@hirez.programming.kicks-ass.net/

Thanks for reminding, i will use this API in next revision.
> -- Steve
>
>
>> +
>> + return page;
>> +}
>> +#endif
>> +
>

--
BR,
Liao, Chang

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