Commit 36de1e42 authored by Mike Rapoport (Microsoft)'s avatar Mike Rapoport (Microsoft) Committed by Andrew Morton
Browse files

x86/kprobes: enable EXECMEM_ROX_CACHE for kprobes allocations 

x86::alloc_insn_page() always allocates ROX memory.

Instead of overriding this method, add EXECMEM_KPROBES entry in
execmem_info with pgprot set to PAGE_KERNEL_ROX and use ROX cache when
configuration and CPU features allow it.

Link: https://lkml.kernel.org/r/20250713071730.4117334-8-rppt@kernel.org


Signed-off-by: default avatarMike Rapoport (Microsoft) <rppt@kernel.org>
Acked-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: default avatarMasami Hiramatsu (Google) <mhiramat@kernel.org>
Cc: Daniel Gomez <da.gomez@samsung.com>
Cc: Petr Pavlu <petr.pavlu@suse.com>
Cc: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent ab674b68

arch/x86/kernel/kprobes/core.c

+0 −18
Original line number Diff line number Diff line
@@ -481,24 +481,6 @@ static int prepare_singlestep(kprobe_opcode_t *buf, struct kprobe *p, 
	return len;

}



/* Make page to RO mode when allocate it */

void *alloc_insn_page(void)

{

	void *page;



	page = execmem_alloc(EXECMEM_KPROBES, PAGE_SIZE);

	if (!page)

		return NULL;



	/*

	 * TODO: Once additional kernel code protection mechanisms are set, ensure

	 * that the page was not maliciously altered and it is still zeroed.

	 */

	set_memory_rox((unsigned long)page, 1);



	return page;

}



/* Kprobe x86 instruction emulation - only regs->ip or IF flag modifiers */



static void kprobe_emulate_ifmodifiers(struct kprobe *p, struct pt_regs *regs)

arch/x86/mm/init.c

+8 −1
Original line number Diff line number Diff line
@@ -1098,7 +1098,14 @@ struct execmem_info __init *execmem_arch_setup(void) 
				.pgprot	= pgprot,

				.alignment = MODULE_ALIGN,

			},

			[EXECMEM_KPROBES ... EXECMEM_BPF] = {

			[EXECMEM_KPROBES] = {

				.flags	= flags,

				.start	= start,

				.end	= MODULES_END,

				.pgprot	= PAGE_KERNEL_ROX,

				.alignment = MODULE_ALIGN,

			},

			[EXECMEM_FTRACE ... EXECMEM_BPF] = {

				.flags	= EXECMEM_KASAN_SHADOW,

				.start	= start,

				.end	= MODULES_END,