From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AH8x227o7VuvSHLjC70YkjvJUSKKI5WTIH5T5L1EU7OZNE80mwTmWOPhtJU2bu61QSW9oNtR8175 ARC-Seal: i=1; a=rsa-sha256; t=1518168356; cv=none; d=google.com; s=arc-20160816; b=SKdDa1R0FrK2lKEfRGIyfKvQlUZ8B/sCmiNNiYvi+/LSVmPNqSj7MZfHrJLxdPDmkG DUGxHFxrkyXd9R4gvYRhjIQQMQyQB3bHepxv4oJx9ULcwsa9BkoaTLKGGnwkaWLpoZE6 gDXW2FBqJGz/g1XexAo2eZmEQ2QMHh1MoxDqHfC4qOe9ClS41MQtkJt57kvtJ6mOtdhU wbTAIsmrFE4nnJp3mVjW7HpImmz/W0ioi67d/WeG/7Xr439G7l7r+skpFw4Mc8OlYUe9 VAgiEVEE5K/LjgN7+o8Jx42dRXi5BQby9EvYLyVKwhsXDOimohACeeMDd1s4QF8VdXH0 C/PA== 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=KtkOAsjyTyoKqzZkfi5gFA7NSyniyvnBjfnVFAE+6eMw/JTbPM5Z7VZHQYssDT9AQo F0gzn17eYcU3DSPKfg8vGCdsabdXXgVz+UcOPkJUqVpenLM74XL5ELcFTVk09lOKqGvd WRF7CKH9F7UkyAt0HEfmONjKZd4tpDC+9va5ZGux/viT6MjgmL1AEg79laJnYmj4R5wO ikjoykdtq2S2ZLlPP7bevqKCGCPA50XuPqsv8g9zPmTXeUG7qiDPI+NImNET7q2cByAx Jx+TGuMfVaS2DaEFXP28BV5MFto8bXU1pDRtNQtuUJdXud5nsAOOqBXg7vfreIW/JGB+ cGzQ== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass (test mode) header.i=@8bytes.org header.s=mail-1 header.b=l0dR+8Nn; spf=pass (google.com: domain of joro@8bytes.org designates 81.169.241.247 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=l0dR+8Nn; spf=pass (google.com: domain of joro@8bytes.org designates 81.169.241.247 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 06/31] x86/entry/32: Split off return-to-kernel path Date: Fri, 9 Feb 2018 10:25:15 +0100 Message-Id: <1518168340-9392-7-git-send-email-joro@8bytes.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1518168340-9392-1-git-send-email-joro@8bytes.org> References: <1518168340-9392-1-git-send-email-joro@8bytes.org> X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: =?utf-8?q?1591914902552804674?= X-GMAIL-MSGID: =?utf-8?q?1591914902552804674?= 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