linux-kernel - [PATCH 6/6] x86, mm: x86, mm: jump to split only 4K range when range doesn't span PMD

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]

Date:   Tue, 12 Feb 2019 10:12:15 +0800
From:   Wei Yang <richardw.yang@...ux.intel.com>
To:     x86@...nel.org, linux-kernel@...r.kernel.org
Cc:     dave.hansen@...ux.intel.com, luto@...nel.org, peterz@...radead.or,
        tglx@...utronix.de, Wei Yang <richardw.yang@...ux.intel.com>
Subject: [PATCH 6/6] x86, mm: x86, mm: jump to split only 4K range when range doesn't span PMD

In case the first attempt to round_up pfn with PMD_SIZE exceed the
limit_pfn, this means we could only have 4K range.

This patch jumps to split only 4K range for this case.

Signed-off-by: Wei Yang <richardw.yang@...ux.intel.com>
---
 arch/x86/mm/init.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c
index cbb105388f24..bf422a637035 100644
--- a/arch/x86/mm/init.c
+++ b/arch/x86/mm/init.c
@@ -383,7 +383,7 @@ static int __meminit split_mem_range(struct map_range *mr,
 	end_pfn = round_up(pfn, PFN_DOWN(PMD_SIZE));
 #endif
 	if (end_pfn > limit_pfn)
-		end_pfn = limit_pfn;
+		goto only_4K_range;
 	if (start_pfn < end_pfn) {
 		nr_range = save_mr(mr, nr_range, start_pfn, end_pfn, 0);
 		pfn = end_pfn;
@@ -435,6 +435,7 @@ static int __meminit split_mem_range(struct map_range *mr,
 	 * Range (E):
 	 * tail is not big page (2M) alignment
 	 */
+only_4K_range:
 	start_pfn = pfn;
 	end_pfn = limit_pfn;
 	nr_range = save_mr(mr, nr_range, start_pfn, end_pfn, 0);
-- 
2.19.1