Commit b73c8ccc authored by Christophe Leroy's avatar Christophe Leroy Committed by Michael Ellerman
Browse files

powerpc/kprobes: Replace ppc_optinsn by common optinsn 



Commit 51c9c084 ("powerpc/kprobes: Implement Optprobes")
implemented a powerpc specific version of optinsn in order
to workaround the 32Mb limitation for direct branches.

Instead of implementing a dedicated powerpc version, use the
common optinsn and override the allocation and freeing functions.

This also indirectly remove the CLANG warning about
is_kprobe_ppc_optinsn_slot() not being use, and the powerpc will
now benefit from commit 5b485629 ("kprobes, extable: Identify
kprobes trampolines as kernel text area")

Suggested-by: default avatarMasami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: default avatarChristophe Leroy <christophe.leroy@csgroup.eu>
Acked-by: default avatarMasami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/ec5e85f9f9abcfecc959a03495f4a7858eb4d203.1620896780.git.christophe.leroy@csgroup.eu
parent 7ee3e97e

arch/powerpc/kernel/optprobes.c

+5 −18
Original line number Diff line number Diff line
@@ -31,11 +31,9 @@ 
#define TMPL_END_IDX		\

	(optprobe_template_end - optprobe_template_entry)



DEFINE_INSN_CACHE_OPS(ppc_optinsn);



static bool insn_page_in_use;



static void *__ppc_alloc_insn_page(void)

void *alloc_optinsn_page(void)

{

	if (insn_page_in_use)

		return NULL;
@@ -43,20 +41,11 @@ static void *__ppc_alloc_insn_page(void) 
	return &optinsn_slot;

}



static void __ppc_free_insn_page(void *page __maybe_unused)

void free_optinsn_page(void *page)

{

	insn_page_in_use = false;

}



struct kprobe_insn_cache kprobe_ppc_optinsn_slots = {

	.mutex = __MUTEX_INITIALIZER(kprobe_ppc_optinsn_slots.mutex),

	.pages = LIST_HEAD_INIT(kprobe_ppc_optinsn_slots.pages),

	/* insn_size initialized later */

	.alloc = __ppc_alloc_insn_page,

	.free = __ppc_free_insn_page,

	.nr_garbage = 0,

};



/*

 * Check if we can optimize this probe. Returns NIP post-emulation if this can

 * be optimized and 0 otherwise.
@@ -136,7 +125,7 @@ NOKPROBE_SYMBOL(optimized_callback); 
void arch_remove_optimized_kprobe(struct optimized_kprobe *op)

{

	if (op->optinsn.insn) {

		free_ppc_optinsn_slot(op->optinsn.insn, 1);

		free_optinsn_slot(op->optinsn.insn, 1);

		op->optinsn.insn = NULL;

	}

}
@@ -203,14 +192,12 @@ int arch_prepare_optimized_kprobe(struct optimized_kprobe *op, struct kprobe *p) 
	unsigned long nip, size;

	int rc, i;



	kprobe_ppc_optinsn_slots.insn_size = MAX_OPTINSN_SIZE;



	nip = can_optimize(p);

	if (!nip)

		return -EILSEQ;



	/* Allocate instruction slot for detour buffer */

	buff = get_ppc_optinsn_slot();

	buff = get_optinsn_slot();

	if (!buff)

		return -ENOMEM;
@@ -297,7 +284,7 @@ int arch_prepare_optimized_kprobe(struct optimized_kprobe *op, struct kprobe *p) 
	return 0;



error:

	free_ppc_optinsn_slot(buff, 0);

	free_optinsn_slot(buff, 0);

	return -ERANGE;



}