From: David Hildenbrand <david@xxxxxxxxxx> Subject: powerpc/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. Link: http://lkml.kernel.org/r/20190114125903.24845-4-david@xxxxxxxxxx Signed-off-by: David Hildenbrand <david@xxxxxxxxxx> Acked-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx> [powerpc] Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx> Cc: Paul Mackerras <paulus@xxxxxxxxx> Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx> Cc: Christophe Leroy <christophe.leroy@xxxxxx> Cc: Kees Cook <keescook@xxxxxxxxxxxx> Cc: Michal Hocko <mhocko@xxxxxxxxxx> Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- arch/powerpc/kernel/vdso.c | 2 -- 1 file changed, 2 deletions(-) --- a/arch/powerpc/kernel/vdso.c~powerpc-vdso-dont-clear-pg_reserved +++ a/arch/powerpc/kernel/vdso.c @@ -798,7 +798,6 @@ static int __init vdso_init(void) BUG_ON(vdso32_pagelist == NULL); for (i = 0; i < vdso32_pages; i++) { struct page *pg = virt_to_page(vdso32_kbase + i*PAGE_SIZE); - ClearPageReserved(pg); get_page(pg); vdso32_pagelist[i] = pg; } @@ -812,7 +811,6 @@ static int __init vdso_init(void) BUG_ON(vdso64_pagelist == NULL); for (i = 0; i < vdso64_pages; i++) { struct page *pg = virt_to_page(vdso64_kbase + i*PAGE_SIZE); - ClearPageReserved(pg); get_page(pg); vdso64_pagelist[i] = pg; } _
