linux-kernel - [PATCH v8 5/6] arm: arm64: introduce pfn_valid

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <1523431317-30612-6-git-send-email-hejianet@gmail.com>
Date:   Wed, 11 Apr 2018 00:21:56 -0700
From:   Jia He <hejianet@...il.com>
To:     Russell King <linux@...linux.org.uk>,
        Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will.deacon@....com>,
        Mark Rutland <mark.rutland@....com>,
        Ard Biesheuvel <ard.biesheuvel@...aro.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Michal Hocko <mhocko@...e.com>
Cc:     Wei Yang <richard.weiyang@...il.com>,
        Kees Cook <keescook@...omium.org>,
        Laura Abbott <labbott@...hat.com>,
        Vladimir Murzin <vladimir.murzin@....com>,
        Philip Derrin <philip@....systems>,
        AKASHI Takahiro <takahiro.akashi@...aro.org>,
        James Morse <james.morse@....com>,
        Steve Capper <steve.capper@....com>,
        Pavel Tatashin <pasha.tatashin@...cle.com>,
        Gioh Kim <gi-oh.kim@...fitbricks.com>,
        Vlastimil Babka <vbabka@...e.cz>, Mel Gorman <mgorman@...e.de>,
        Johannes Weiner <hannes@...xchg.org>,
        Kemi Wang <kemi.wang@...el.com>,
        Petr Tesarik <ptesarik@...e.com>,
        YASUAKI ISHIMATSU <yasu.isimatu@...il.com>,
        Andrey Ryabinin <aryabinin@...tuozzo.com>,
        Nikolay Borisov <nborisov@...e.com>,
        Daniel Jordan <daniel.m.jordan@...cle.com>,
        Daniel Vacek <neelx@...hat.com>,
        Eugeniu Rosca <erosca@...adit-jv.com>,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        linux-mm@...ck.org, Jia He <hejianet@...il.com>,
        Jia He <jia.he@...-semitech.com>
Subject: [PATCH v8 5/6] arm: arm64: introduce pfn_valid_region()

Commit b92df1de5d28 ("mm: page_alloc: skip over regions of invalid pfns
where possible") optimized the loop in memmap_init_zone(). But there is
still some room for improvement. E.g. in early_pfn_valid(), we can record
the last returned memblock region. If current pfn and last pfn are in the
same memory region, we needn't do the unnecessary binary searches because
memblock_is_nomap is the same result for whole memory region.

Signed-off-by: Jia He <jia.he@...-semitech.com>
---
 include/linux/early_pfn.h | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/include/linux/early_pfn.h b/include/linux/early_pfn.h
index f9e40c3..9609391 100644
--- a/include/linux/early_pfn.h
+++ b/include/linux/early_pfn.h
@@ -51,5 +51,29 @@ ulong __init_memblock memblock_next_valid_pfn(ulong pfn)
 	return PHYS_PFN(regions[early_region_idx].base);
 }
 EXPORT_SYMBOL(memblock_next_valid_pfn);
+
+int pfn_valid_region(ulong pfn)
+{
+	ulong start_pfn, end_pfn;
+	struct memblock_type *type = &memblock.memory;
+	struct memblock_region *regions = type->regions;
+
+	if (early_region_idx != -1) {
+		start_pfn = PFN_DOWN(regions[early_region_idx].base);
+		end_pfn = PFN_DOWN(regions[early_region_idx].base +
+					regions[early_region_idx].size);
+
+		if (pfn >= start_pfn && pfn < end_pfn)
+			return !memblock_is_nomap(
+					&regions[early_region_idx]);
+	}
+
+	early_region_idx = memblock_search_pfn_regions(pfn);
+	if (early_region_idx == -1)
+		return false;
+
+	return !memblock_is_nomap(&regions[early_region_idx]);
+}
+EXPORT_SYMBOL(pfn_valid_region);
 #endif /*CONFIG_HAVE_MEMBLOCK_PFN_VALID*/
 #endif /*__EARLY_PFN_H*/
-- 
2.7.4