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From:   Song Shuai <suagrfillet@gmail.com>
To:     paul.walmsley@sifive.com, palmer@dabbelt.com,
        aou@eecs.berkeley.edu, akpm@linux-foundation.org,
        guoren@kernel.org, alexghiti@rivosinc.com,
        sergey.matyukevich@syntacore.com, david@redhat.com,
        wangkefeng.wang@huawei.com, panqinglin2020@iscas.ac.cn,
        woodrow.shen@sifive.com
Cc:     linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org,
        Song Shuai <suagrfillet@gmail.com>
Subject: [PATCH] riscv: Correct the MODULES_VADDR
Date:   Tue,  1 Aug 2023 19:10:14 +0800
Message-Id: <20230801111014.1432679-1-suagrfillet@gmail.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

As Documentation/riscv/vm-layout.rst describes, the 2G-sized "modules, BPF"
area should lie right before the "kernel" area. But the current definition
of MODULES_VADDR isn't consistent with that, so correct it.

Before this patch, the size of "modules" from print_vm_layout() is not 2G.

[    0.000000]      modules : 0xffffffff2ff2f000 - 0xffffffffae600000 (2022 MB)
[    0.000000]       lowmem : 0xff60000000000000 - 0xff60000040000000 (1024 MB)
[    0.000000]       kernel : 0xffffffffae600000 - 0xffffffffffffffff (1305 MB)

After this patch, the size is 2G.

[    0.000000]      modules : 0xffffffff3a000000 - 0xffffffffba000000 (2048 MB)
[    0.000000]       lowmem : 0xff60000000000000 - 0xff60000040000000 (1024 MB)
[    0.000000]       kernel : 0xffffffffba000000 - 0xffffffffffffffff (1119 MB)

Signed-off-by: Song Shuai <suagrfillet@gmail.com>
---
 arch/riscv/include/asm/pgtable.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h
index 75970ee2bda2..7c57e17fc758 100644
--- a/arch/riscv/include/asm/pgtable.h
+++ b/arch/riscv/include/asm/pgtable.h
@@ -53,8 +53,8 @@
 #ifdef CONFIG_64BIT
 /* This is used to define the end of the KASAN shadow region */
 #define MODULES_LOWEST_VADDR	(KERNEL_LINK_ADDR - SZ_2G)
-#define MODULES_VADDR		(PFN_ALIGN((unsigned long)&_end) - SZ_2G)
 #define MODULES_END		(PFN_ALIGN((unsigned long)&_start))
+#define MODULES_VADDR		(MODULES_END - SZ_2G)
 #endif
 
 /*
-- 
2.20.1