Commit 6376ed8f authored by Christophe Leroy's avatar Christophe Leroy Committed by Michael Ellerman
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powerpc/bpf/32: No need to zeroise r4 when not doing tail call 



r4 is cleared at function entry and used as tail call count.

But when the function does not perform tail call, r4 is
ignored, so no need to clear it.

Replace it by a NOP in that case.

Signed-off-by: default avatarChristophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/9c5440b2b6d90a78600257433ac499b5c5101fbb.1675245773.git.christophe.leroy@csgroup.eu
parent d9ab6da6

arch/powerpc/net/bpf_jit_comp32.c

+4 −1
Original line number Diff line number Diff line
@@ -114,7 +114,10 @@ void bpf_jit_build_prologue(u32 *image, struct codegen_context *ctx) 
	int i;



	/* Initialize tail_call_cnt, to be skipped if we do tail calls. */

	if (ctx->seen & SEEN_TAILCALL)

		EMIT(PPC_RAW_LI(_R4, 0));

	else

		EMIT(PPC_RAW_NOP());



#define BPF_TAILCALL_PROLOGUE_SIZE	4