linux-kernel - [PATCH 1/6] MIPS: Loongson64: Do not write the read only field LPA of CP0

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Date:   Thu, 29 Oct 2020 16:02:56 +0800
From:   Tiezhu Yang <yangtiezhu@...ngson.cn>
To:     Thomas Bogendoerfer <tsbogend@...ha.franken.de>,
        Huacai Chen <chenhc@...ote.com>,
        Jiaxun Yang <jiaxun.yang@...goat.com>
Cc:     linux-mips@...r.kernel.org, linux-kernel@...r.kernel.org,
        Xuefeng Li <lixuefeng@...ngson.cn>
Subject: [PATCH 1/6] MIPS: Loongson64: Do not write the read only field LPA of CP0_CONFIG3

The field LPA of CP0_CONFIG3 register is read only for Loongson64, so the
write operations are meaningless, remove them.

Signed-off-by: Tiezhu Yang <yangtiezhu@...ngson.cn>
---
 arch/mips/include/asm/mach-loongson64/kernel-entry-init.h | 8 --------
 arch/mips/loongson64/numa.c                               | 3 ---
 2 files changed, 11 deletions(-)

diff --git a/arch/mips/include/asm/mach-loongson64/kernel-entry-init.h b/arch/mips/include/asm/mach-loongson64/kernel-entry-init.h
index 87a5bfb..e4d77f4 100644
--- a/arch/mips/include/asm/mach-loongson64/kernel-entry-init.h
+++ b/arch/mips/include/asm/mach-loongson64/kernel-entry-init.h
@@ -19,10 +19,6 @@
 	.macro	kernel_entry_setup
 	.set	push
 	.set	mips64
-	/* Set LPA on LOONGSON3 config3 */
-	mfc0	t0, CP0_CONFIG3
-	or	t0, (0x1 << 7)
-	mtc0	t0, CP0_CONFIG3
 	/* Set ELPA on LOONGSON3 pagegrain */
 	mfc0	t0, CP0_PAGEGRAIN
 	or	t0, (0x1 << 29)
@@ -54,10 +50,6 @@
 	.macro	smp_slave_setup
 	.set	push
 	.set	mips64
-	/* Set LPA on LOONGSON3 config3 */
-	mfc0	t0, CP0_CONFIG3
-	or	t0, (0x1 << 7)
-	mtc0	t0, CP0_CONFIG3
 	/* Set ELPA on LOONGSON3 pagegrain */
 	mfc0	t0, CP0_PAGEGRAIN
 	or	t0, (0x1 << 29)
diff --git a/arch/mips/loongson64/numa.c b/arch/mips/loongson64/numa.c
index cf9459f..c7e3cced 100644
--- a/arch/mips/loongson64/numa.c
+++ b/arch/mips/loongson64/numa.c
@@ -40,9 +40,6 @@ static void enable_lpa(void)
 	unsigned long value;
 
 	value = __read_32bit_c0_register($16, 3);
-	value |= 0x00000080;
-	__write_32bit_c0_register($16, 3, value);
-	value = __read_32bit_c0_register($16, 3);
 	pr_info("CP0_Config3: CP0 16.3 (0x%lx)\n", value);
 
 	value = __read_32bit_c0_register($5, 1);
-- 
2.1.0