linux-kernel - [PATCH] riscv: mm: Remove setup_zero

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Date:   Fri, 7 May 2021 22:19:59 +0800
From:   Jisheng Zhang <jszhang3@...l.ustc.edu.cn>
To:     Paul Walmsley <paul.walmsley@...ive.com>,
        Palmer Dabbelt <palmer@...belt.com>,
        Albert Ou <aou@...s.berkeley.edu>
Cc:     linux-riscv@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: [PATCH] riscv: mm: Remove setup_zero_page()

The empty_zero_page sits at .bss..page_aligned section, so will be
cleared to zero during clearing bss, we don't need to clear it again.

Signed-off-by: Jisheng Zhang <jszhang@...nel.org>
Reviewed-by: Anup Patel <anup@...infault.org>
---

Hi Palmer,

This patch was one of v3 series of "riscv: improve self-protection"
and acked by Anup. I checked Linus tree this tonight, it seems the v2 or
v1 was merged, this patch is missing, so I rebased and sent out this patch.
If it's late for linux-5.13, then I can rebase again once linux-5.13-rc1
is released.

Thanks in advance

 arch/riscv/mm/init.c | 6 ------
 1 file changed, 6 deletions(-)

diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
index dfb5e4f7a670..4a68b029e3d2 100644
--- a/arch/riscv/mm/init.c
+++ b/arch/riscv/mm/init.c
@@ -67,11 +67,6 @@ static void __init zone_sizes_init(void)
 	free_area_init(max_zone_pfns);
 }
 
-static void __init setup_zero_page(void)
-{
-	memset((void *)empty_zero_page, 0, PAGE_SIZE);
-}
-
 #if defined(CONFIG_MMU) && defined(CONFIG_DEBUG_VM)
 static inline void print_mlk(char *name, unsigned long b, unsigned long t)
 {
@@ -862,7 +857,6 @@ RESERVEDMEM_OF_DECLARE(elfcorehdr, "linux,elfcorehdr", elfcore_hdr_setup);
 void __init paging_init(void)
 {
 	setup_vm_final();
-	setup_zero_page();
 }
 
 void __init misc_mem_init(void)
-- 
2.31.0