On Thu, 18 Jun 2020 08:43:06 +0200 Christoph Hellwig <hch@xxxxxx> wrote:
> Use PAGE_KERNEL_ROX directly instead of allocating RWX and setting the
> page read-only just after the allocation.
>
> --- a/arch/arm64/kernel/probes/kprobes.c
> +++ b/arch/arm64/kernel/probes/kprobes.c
> @@ -120,15 +120,9 @@ int __kprobes arch_prepare_kprobe(struct kprobe *p)
>
> void *alloc_insn_page(void)
> {
> - void *page;
> -
> - page = vmalloc_exec(PAGE_SIZE);
> - if (page) {
> - set_memory_ro((unsigned long)page, 1);
> - set_vm_flush_reset_perms(page);
> - }
> -
> - return page;
> + return __vmalloc_node_range(PAGE_SIZE, 1, VMALLOC_START, VMALLOC_END,
> + GFP_KERNEL, PAGE_KERNEL_ROX, VM_FLUSH_RESET_PERMS,
> + NUMA_NO_NODE, __func__);
> }
>
> /* arm kprobe: install breakpoint in text */
But why. I think this is just a cleanup, doesn't address any runtime issue?
