[PATCH] target/ppc/translate: Add dummy implementation for dcblc instruction

From: Bernhard Beschow <shentey@gmail.com>
To: qemu-devel@nongnu.org
Cc: "Cédric Le Goater" <clg@kaod.org>,
	qemu-ppc@nongnu.org,
	"Daniel Henrique Barboza" <danielhb413@gmail.com>,
	"Greg Kurz" <groug@kaod.org>,
	"David Gibson" <david@gibson.dropbear.id.au>,
	"Bernhard Beschow" <shentey@gmail.com>
Subject: [PATCH] target/ppc/translate: Add dummy implementation for dcblc instruction
Date: Mon, 30 Jan 2023 19:49:50 +0100	[thread overview]
Message-ID: <20230130184950.5241-1-shentey@gmail.com> (raw)

The dcblc instruction is used by u-boot in mpc85xx/start.S. Without it,
an illegal istruction exception is generated very early in the boot
process where the processor is not yet able to handle exceptions. See:

https://github.com/u-boot/u-boot/blob/v2023.01/arch/powerpc/cpu/mpc85xx/start.S#L1840

Signed-off-by: Bernhard Beschow <shentey@gmail.com>
---
 target/ppc/translate.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/target/ppc/translate.c b/target/ppc/translate.c
index edb3daa9b5..8c32e697d9 100644
--- a/target/ppc/translate.c
+++ b/target/ppc/translate.c
@@ -5261,6 +5261,14 @@ static void gen_dcbtls(DisasContext *ctx)
     tcg_temp_free(t0);
 }
 
+/* dcblc */
+static void gen_dcblc(DisasContext *ctx)
+{
+    /*
+     * interpreted as no-op
+     */
+}
+
 /* dcbz */
 static void gen_dcbz(DisasContext *ctx)
 {
@@ -6832,6 +6840,7 @@ GEN_HANDLER_E(dcbtep, 0x1F, 0x1F, 0x09, 0x00000001, PPC_NONE, PPC2_BOOKE206),
 GEN_HANDLER(dcbtst, 0x1F, 0x16, 0x07, 0x00000001, PPC_CACHE),
 GEN_HANDLER_E(dcbtstep, 0x1F, 0x1F, 0x07, 0x00000001, PPC_NONE, PPC2_BOOKE206),
 GEN_HANDLER_E(dcbtls, 0x1F, 0x06, 0x05, 0x02000001, PPC_BOOKE, PPC2_BOOKE206),
+GEN_HANDLER_E(dcblc, 0x1F, 0x06, 0x0c, 0x02000001, PPC_BOOKE, PPC2_BOOKE206),
 GEN_HANDLER(dcbz, 0x1F, 0x16, 0x1F, 0x03C00001, PPC_CACHE_DCBZ),
 GEN_HANDLER_E(dcbzep, 0x1F, 0x1F, 0x1F, 0x03C00001, PPC_NONE, PPC2_BOOKE206),
 GEN_HANDLER(dst, 0x1F, 0x16, 0x0A, 0x01800001, PPC_ALTIVEC),
-- 
2.39.1


