linux-kernel - [PATCH RFC 4/7] riscv/vdso: don't clear PG

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Message-Id: <20181205122851.5891-5-david@redhat.com>
Date:   Wed,  5 Dec 2018 13:28:48 +0100
From:   David Hildenbrand <david@...hat.com>
To:     linux-mm@...ck.org
Cc:     linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-m68k@...ts.linux-m68k.org, linuxppc-dev@...ts.ozlabs.org,
        linux-riscv@...ts.infradead.org, linux-s390@...r.kernel.org,
        linux-mediatek@...ts.infradead.org,
        David Hildenbrand <david@...hat.com>,
        Palmer Dabbelt <palmer@...ive.com>,
        Albert Ou <aou@...s.berkeley.edu>,
        Tobias Klauser <tklauser@...tanz.ch>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Michal Hocko <mhocko@...nel.org>,
        Matthew Wilcox <willy@...radead.org>
Subject: [PATCH RFC 4/7] riscv/vdso: don't clear PG_reserved

The VDSO is part of the kernel image and therefore the struct pages are
marked as reserved during boot.

As we install a special mapping, the actual struct pages will never be
exposed to MM via the page tables. We can therefore leave the pages
marked as reserved.

Cc: Palmer Dabbelt <palmer@...ive.com>
Cc: Albert Ou <aou@...s.berkeley.edu>
Cc: Tobias Klauser <tklauser@...tanz.ch>
Cc: Andrew Morton <akpm@...ux-foundation.org>
Cc: Michal Hocko <mhocko@...nel.org>
Cc: Matthew Wilcox <willy@...radead.org>
Signed-off-by: David Hildenbrand <david@...hat.com>
---
 arch/riscv/kernel/vdso.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/arch/riscv/kernel/vdso.c b/arch/riscv/kernel/vdso.c
index 582cb153eb24..0cd044122234 100644
--- a/arch/riscv/kernel/vdso.c
+++ b/arch/riscv/kernel/vdso.c
@@ -54,7 +54,6 @@ static int __init vdso_init(void)
 		struct page *pg;
 
 		pg = virt_to_page(vdso_start + (i << PAGE_SHIFT));
-		ClearPageReserved(pg);
 		vdso_pagelist[i] = pg;
 	}
 	vdso_pagelist[i] = virt_to_page(vdso_data);
-- 
2.17.2