linux-kernel - [PATCH v4 2/6] x86/mm/KASLR: Open code unnecessary function get

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: <20190314094645.4883-3-bhe@redhat.com>
Date:   Thu, 14 Mar 2019 17:46:41 +0800
From:   Baoquan He <bhe@...hat.com>
To:     linux-kernel@...r.kernel.org
Cc:     mingo@...nel.org, keescook@...omium.org, kirill@...temov.name,
        yamada.masahiro@...ionext.com, tglx@...utronix.de, bp@...en8.de,
        hpa@...or.com, dave.hansen@...ux.intel.com, luto@...nel.org,
        peterz@...radead.org, x86@...nel.org, thgarnie@...gle.com,
        Baoquan He <bhe@...hat.com>
Subject: [PATCH v4 2/6] x86/mm/KASLR: Open code unnecessary function get_padding

It's used only twice and we do bit shifts in the parent function
anyway so it's not like it's hiding some uninteresting detail.

Signed-off-by: Baoquan He <bhe@...hat.com>
Acked-by: Kees Cook <keescook@...omium.org>
---
 arch/x86/mm/kaslr.c | 10 ++--------
 1 file changed, 2 insertions(+), 8 deletions(-)

diff --git a/arch/x86/mm/kaslr.c b/arch/x86/mm/kaslr.c
index 5debf82ab06a..d7ea6b252594 100644
--- a/arch/x86/mm/kaslr.c
+++ b/arch/x86/mm/kaslr.c
@@ -92,12 +92,6 @@ static __initdata struct kaslr_memory_region {
 	{ &vmemmap_base, 1 },
 };
 
-/* Get size in bytes used by the memory region */
-static inline unsigned long get_padding(struct kaslr_memory_region *region)
-{
-	return (region->size_tb << TB_SHIFT);
-}
-
 /*
  * Apply no randomization if KASLR was disabled at boot or if KASAN
  * is enabled. KASAN shadow mappings rely on regions being PGD aligned.
@@ -155,7 +149,7 @@ void __init kernel_randomize_memory(void)
 	/* Calculate entropy available between regions */
 	remain_entropy = vaddr_end - vaddr_start;
 	for (i = 0; i < ARRAY_SIZE(kaslr_regions); i++)
-		remain_entropy -= get_padding(&kaslr_regions[i]);
+		remain_entropy -= kaslr_regions[i].size_tb << TB_SHIFT;
 
 	prandom_seed_state(&rand_state, kaslr_get_random_long("Memory"));
 
@@ -176,7 +170,7 @@ void __init kernel_randomize_memory(void)
 		 * Jump the region and add a minimum padding based on
 		 * randomization alignment.
 		 */
-		vaddr += get_padding(&kaslr_regions[i]);
+		vaddr += kaslr_regions[i].size_tb << TB_SHIFT;
 		vaddr = round_up(vaddr + 1, PUD_SIZE);
 		remain_entropy -= entropy;
 	}
-- 
2.17.2