[PATCH 4.19 07/13] riscv,entry: fix misaligned base for excp_vect_table - Greg Kroah-Hartman

From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	stable@vger.kernel.org, Zihao Yu <yuzihao@ict.ac.cn>,
	Anup Patel <anup@brainfault.org>,
	Palmer Dabbelt <palmerdabbelt@google.com>,
	Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.19 07/13] riscv,entry: fix misaligned base for excp_vect_table
Date: Thu, 15 Apr 2021 16:47:56 +0200	[thread overview]
Message-ID: <20210415144411.843251257@linuxfoundation.org> (raw)
In-Reply-To: <20210415144411.596695196@linuxfoundation.org>

From: Zihao Yu <yuzihao@ict.ac.cn>

[ Upstream commit ac8d0b901f0033b783156ab2dc1a0e73ec42409b ]

In RV64, the size of each entry in excp_vect_table is 8 bytes. If the
base of the table is not 8-byte aligned, loading an entry in the table
will raise a misaligned exception. Although such exception will be
handled by opensbi/bbl, this still causes performance degradation.

Signed-off-by: Zihao Yu <yuzihao@ict.ac.cn>
Reviewed-by: Anup Patel <anup@brainfault.org>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/riscv/kernel/entry.S | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/riscv/kernel/entry.S b/arch/riscv/kernel/entry.S
index a03821b2656a..d9de22686e27 100644
--- a/arch/riscv/kernel/entry.S
+++ b/arch/riscv/kernel/entry.S
@@ -449,6 +449,7 @@ ENDPROC(__fstate_restore)
 
 
 	.section ".rodata"
+	.align LGREG
 	/* Exception vector table */
 ENTRY(excp_vect_table)
 	RISCV_PTR do_trap_insn_misaligned
-- 
2.30.2



