[PATCH] riscv: mm: Remove setup_zero_page()

[PATCH] riscv: mm: Remove setup_zero_page()

[Jisheng Zhang]

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@kernel.org>
Reviewed-by: Anup Patel <anup@brainfault.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

Re: [PATCH] riscv: mm: Remove setup_zero_page()

[Palmer Dabbelt]

On Fri, 07 May 2021 07:19:59 PDT (-0700), jszhang3@mail.ustc.edu.cn wrote:
> 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@kernel.org>
> Reviewed-by: Anup Patel <anup@brainfault.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)

Sorry, I missed this one.  It's on for-next now.