From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AG47ELvWE7mb6bH57w3/s8q3TCafZL/RQmj0LBOTf41nyRztBBGCaBuFkIixWH2joxeChOejBZo2 ARC-Seal: i=1; a=rsa-sha256; t=1520245572; cv=none; d=google.com; s=arc-20160816; b=qXPVIOhv2MpGXRaBpkveeFgH/Pf8B1cYNr3WP6ZTDBC8Pcjwl0MTzcswnQxslHHSIh 6UyTH8M1Yn73DGu/Qy70HoeN1AboThqTo26TW+DUf5N/7tED0Zc5bPdeiq8IUvukQ6gp YpI7IqdZMFUOatbaNMQ+ga9iEQVvXR38QZBZOiCPVpiiTGeOe09KlsuBVmBIR9frDTkx ME+CF7pPR4ozRGNOnX9L1lE+MQvWmKnhZxV/5rec5etfo+JjiS/qQvfTnG4k+55nmYNk l6NNFW6pYNZk2KAP6XatxnAKCv9T+8rk3+x9UMNDoFoOCrzLfNo7QU0HnYlT+6z6pmTd uxMA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=references:in-reply-to:message-id:date:subject:cc:to:from :dkim-signature:arc-authentication-results; bh=c+a2sINmdTrcI8vkYK/XU7EvC9UjG9GZQWNCAcJ90XU=; b=CzGM9GhJW7qyOGUaobrPo3sRsVFuhUAIiOqYdtKhinc+KyrGkPFTHg2d2w7+BhYWLw yzBGueFKfp+fn1qPmq8Ye3RhyHK8+8fvOkvKsKg4HyNuMeO2fIwvzkel+iyj+kdlB20E j4tvO4F3K4qm1ycWBZ6emCk6MaGOPgixUm64JLe0i3kVU20aBkd22XXlpNtbWtf8clzA vhei+XyMNpQ377EtwNVU+aOa4L//rrYWTZHbi/hLHmQOdpo7TXKbb1eS9n/FVD9oJaz1 7n/d07T68Qc85l/e5ouDHY3GIiOJ+KkMFD9Z89txaY+zOnjrPXWqWyQVj2HcDQ7Mwor/ wPZA== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass (test mode) header.i=@8bytes.org header.s=mail-1 header.b=dEU5p3qF; spf=pass (google.com: domain of joro@8bytes.org designates 2a01:238:4383:600:38bc:a715:4b6d:a889 as permitted sender) smtp.mailfrom=joro@8bytes.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=8bytes.org Authentication-Results: mx.google.com; dkim=pass (test mode) header.i=@8bytes.org header.s=mail-1 header.b=dEU5p3qF; spf=pass (google.com: domain of joro@8bytes.org designates 2a01:238:4383:600:38bc:a715:4b6d:a889 as permitted sender) smtp.mailfrom=joro@8bytes.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=8bytes.org From: Joerg Roedel To: Thomas Gleixner , Ingo Molnar , "H . Peter Anvin" Cc: x86@kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Linus Torvalds , Andy Lutomirski , Dave Hansen , Josh Poimboeuf , Juergen Gross , Peter Zijlstra , Borislav Petkov , Jiri Kosina , Boris Ostrovsky , Brian Gerst , David Laight , Denys Vlasenko , Eduardo Valentin , Greg KH , Will Deacon , aliguori@amazon.com, daniel.gruss@iaik.tugraz.at, hughd@google.com, keescook@google.com, Andrea Arcangeli , Waiman Long , Pavel Machek , jroedel@suse.de, joro@8bytes.org Subject: [PATCH 06/34] x86/entry/32: Split off return-to-kernel path Date: Mon, 5 Mar 2018 11:25:35 +0100 Message-Id: <1520245563-8444-7-git-send-email-joro@8bytes.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1520245563-8444-1-git-send-email-joro@8bytes.org> References: <1520245563-8444-1-git-send-email-joro@8bytes.org> X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: =?utf-8?q?1594093020633025871?= X-GMAIL-MSGID: =?utf-8?q?1594093020633025871?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: From: Joerg Roedel Use a separate return path when we know we are returning to the kernel. This allows us to put the PTI cr3-switch and the switch to the entry-stack into the return-to-user path without further checking. Signed-off-by: Joerg Roedel --- arch/x86/entry/entry_32.S | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) diff --git a/arch/x86/entry/entry_32.S b/arch/x86/entry/entry_32.S index 00ae759..9bd7718 100644 --- a/arch/x86/entry/entry_32.S +++ b/arch/x86/entry/entry_32.S @@ -65,7 +65,7 @@ # define preempt_stop(clobbers) DISABLE_INTERRUPTS(clobbers); TRACE_IRQS_OFF #else # define preempt_stop(clobbers) -# define resume_kernel restore_all +# define resume_kernel restore_all_kernel #endif .macro TRACE_IRQS_IRET @@ -400,9 +400,9 @@ ENTRY(resume_kernel) DISABLE_INTERRUPTS(CLBR_ANY) .Lneed_resched: cmpl $0, PER_CPU_VAR(__preempt_count) - jnz restore_all + jnz restore_all_kernel testl $X86_EFLAGS_IF, PT_EFLAGS(%esp) # interrupts off (exception path) ? - jz restore_all + jz restore_all_kernel call preempt_schedule_irq jmp .Lneed_resched END(resume_kernel) @@ -602,6 +602,11 @@ restore_all: .Lirq_return: INTERRUPT_RETURN +restore_all_kernel: + TRACE_IRQS_IRET + RESTORE_REGS 4 + jmp .Lirq_return + .section .fixup, "ax" ENTRY(iret_exc ) pushl $0 # no error code -- 2.7.4