From f7c036c15b5388749bc8de208fb7b19d69c4f6fa Mon Sep 17 00:00:00 2001 From: Johan Almbladh Date: Tue, 5 Oct 2021 18:54:03 +0200 Subject: [PATCH] mips, uasm: Add workaround for Loongson-2F nop CPU errata This patch implements a workaround for the Loongson-2F nop in generated, code, if the existing option CONFIG_CPU_NOP_WORKAROUND is set. Before, the binutils option -mfix-loongson2f-nop was enabled, but no workaround was done when emitting MIPS code. Now, the nop pseudo instruction is emitted as "or ax,ax,zero" instead of the default "sll zero,zero,0". This is consistent with the workaround implemented by binutils. Signed-off-by: Johan Almbladh Signed-off-by: Daniel Borkmann Signed-off-by: Andrii Nakryiko Reviewed-by: Jiaxun Yang Link: https://sourceware.org/legacy-ml/binutils/2009-11/msg00387.html Link: https://lore.kernel.org/bpf/20211005165408.2305108-3-johan.almbladh@anyfinetworks.com --- arch/mips/include/asm/uasm.h | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/arch/mips/include/asm/uasm.h b/arch/mips/include/asm/uasm.h index 5efa4e2..296bcf3 100644 --- a/arch/mips/include/asm/uasm.h +++ b/arch/mips/include/asm/uasm.h @@ -249,7 +249,11 @@ static inline void uasm_l##lb(struct uasm_label **lab, u32 *addr) \ #define uasm_i_bnezl(buf, rs, off) uasm_i_bnel(buf, rs, 0, off) #define uasm_i_ehb(buf) uasm_i_sll(buf, 0, 0, 3) #define uasm_i_move(buf, a, b) UASM_i_ADDU(buf, a, 0, b) +#ifdef CONFIG_CPU_NOP_WORKAROUNDS +#define uasm_i_nop(buf) uasm_i_or(buf, 1, 1, 0) +#else #define uasm_i_nop(buf) uasm_i_sll(buf, 0, 0, 0) +#endif #define uasm_i_ssnop(buf) uasm_i_sll(buf, 0, 0, 1) static inline void uasm_i_drotr_safe(u32 **p, unsigned int a1, -- 2.7.4