linux-kernel - [PATCH 5/6] x86/fpu: Remove check

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,  5 Apr 2016 08:29:54 +0200
From:	Borislav Petkov <bp@...en8.de>
To:	X86 ML <x86@...nel.org>
Cc:	LKML <linux-kernel@...r.kernel.org>
Subject: [PATCH 5/6] x86/fpu: Remove check_fpu() indirection

From: Borislav Petkov <bp@...e.de>

Rename it to fpu__init_check_bugs() and do the CPU feature check at
entry, thus getting rid of the old fpu__init_check_bugs() wrapper.

Signed-off-by: Borislav Petkov <bp@...e.de>
---
 arch/x86/kernel/fpu/bugs.c | 16 +++++-----------
 1 file changed, 5 insertions(+), 11 deletions(-)

diff --git a/arch/x86/kernel/fpu/bugs.c b/arch/x86/kernel/fpu/bugs.c
index 224b5ec52195..aad34aafc0e0 100644
--- a/arch/x86/kernel/fpu/bugs.c
+++ b/arch/x86/kernel/fpu/bugs.c
@@ -21,11 +21,15 @@ static double __initdata y = 3145727.0;
  * We should really only care about bugs here
  * anyway. Not features.
  */
-static void __init check_fpu(void)
+void __init fpu__init_check_bugs(void)
 {
 	u32 cr0_saved;
 	s32 fdiv_bug;
 
+	/* kernel_fpu_begin/end() relies on patched alternative instructions. */
+	if (!boot_cpu_has(X86_FEATURE_FPU))
+		return;
+
 	/* We might have CR0::TS set already, clear it: */
 	cr0_saved = read_cr0();
 	write_cr0(cr0_saved & ~X86_CR0_TS);
@@ -59,13 +63,3 @@ static void __init check_fpu(void)
 		pr_warn("Hmm, FPU with FDIV bug\n");
 	}
 }
-
-void __init fpu__init_check_bugs(void)
-{
-	/*
-	 * kernel_fpu_begin/end() in check_fpu() relies on the patched
-	 * alternative instructions.
-	 */
-	if (boot_cpu_has(X86_FEATURE_FPU))
-		check_fpu();
-}
-- 
2.7.3