linux-kernel - [RFC patch 13/15] arm64/entry: Move FPU restore out of exit_to

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: <20190919150809.754111224@linutronix.de>
Date:   Thu, 19 Sep 2019 17:03:27 +0200
From:   Thomas Gleixner <tglx@...utronix.de>
To:     LKML <linux-kernel@...r.kernel.org>
Cc:     x86@...nel.org, Peter Zijlstra <peterz@...radead.org>,
        Andy Lutomirski <luto@...nel.org>,
        Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Marc Zyngier <maz@...nel.org>,
        Paolo Bonzini <pbonzini@...hat.com>, kvm@...r.kernel.org,
        linux-arch@...r.kernel.org
Subject: [RFC patch 13/15] arm64/entry: Move FPU restore out of
 exit_to_usermode() loop

Restoring the FPU is not required to be insided the loop. The final point
to do that is before returning to user space. Move it there.

Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
---
 arch/arm64/include/asm/entry-common.h |    9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

--- a/arch/arm64/include/asm/entry-common.h
+++ b/arch/arm64/include/asm/entry-common.h
@@ -7,8 +7,6 @@
 
 #include <asm/daifflags.h>
 
-#define ARCH_EXIT_TO_USERMODE_WORK	(_TIF_FOREIGN_FPSTATE)
-
 static inline void local_irq_enable_exit_to_user(unsigned long ti_work)
 {
 	if (ti_work & _TIF_NEED_RESCHED)
@@ -24,15 +22,14 @@ static inline void local_irq_disable_exi
 }
 #define local_irq_disable_exit_to_user local_irq_disable_exit_to_user
 
-static inline void arch_exit_to_usermode_work(struct pt_regs *regs,
-					      unsigned long ti_work)
+static inline void arch_exit_to_usermode(struct pt_regs *regs,
+					 unsigned long ti_work)
 {
-	/* Must this be inside the work loop ? */
 	if (ti_work & _TIF_FOREIGN_FPSTATE)
 		fpsimd_restore_current_state();
 
 }
-#define arch_exit_to_usermode_work arch_exit_to_usermode_work
+#define arch_exit_to_usermode arch_exit_to_usermode
 
 enum ptrace_syscall_dir {
 	PTRACE_SYSCALL_ENTER = 0,