From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AIpwx49sWGNLXc7mBtAxoDWw2UPy0Ic6flxCqHQLsVPYp66Sa06g1Bl+OL7XVIACQzpcsSxAvLO7 ARC-Seal: i=1; a=rsa-sha256; t=1523892343; cv=none; d=google.com; s=arc-20160816; b=cwBgKlEV3qVFPzL+cFvgybjvHgofoK4DvXF0skAH8Pa+Y8UlAW4dLDMTcJzDuJCVza U8UNHdbVC3nCXeqDnS38723HBDNo1wVrnQ6DNgJIvs3W4A0UBKhXw5UqWlICPlm2H7tU NJU27FTIFY8ecQ2OS3/iubNpCim0AdrR3vBxn04cMVezvBzYVhyqcmbNJCohwnLODiUX +C/BiSQFKD4cC6pEUpZ4UOG+JneC95JSIKsHE8YWdd2Pgv3tNjOvUndp+LHo3aelkPTb QPe6JylQfckcdy7Hy6EqSc8uwBMfgDvcRHyrkejgzLlAYwam2zW13V90LS+K03URYYz2 iShQ== 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=As1QK1SfZFoKkepHCdFdNR8IF6nzgbilli2hGnAj1fI=; b=XG7xcerTYW38NOdKqz17JIbi0GK1qpEd7I1RCLlJhOl9PXmCW9uy1cLjefnrZ2WvaO QWrQcF9gOnHeelM5LQBFI3yjovRz1tVo4kYinrioXMSbi0brd9dVDT2RaqFeNNSZbxSc rQvKbax2+cjBqEMPSfqi4+4CBYBfuCaoOKE//+OUyP/KOK2f18csFQLy+vEWHSvCJWWW srlmD9o1eNwQer0pfrNyrKYMXBLeYlcMhHaUFeGhkR7MtC67CM9oLLh31dOQ7VsTlolO qeeIRMsdK3jYkKvd80yAjVbwZnzfX4tObtSDrw10FmrnVzfRKYwlxVNnhk2/XzXeMEso N2iQ== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass (test mode) header.i=@8bytes.org header.s=mail-1 header.b=QsEneInO; 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=QsEneInO; 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 , "David H . Gutteridge" , jroedel@suse.de, joro@8bytes.org Subject: [PATCH 06/35] x86/entry/32: Split off return-to-kernel path Date: Mon, 16 Apr 2018 17:24:54 +0200 Message-Id: <1523892323-14741-7-git-send-email-joro@8bytes.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1523892323-14741-1-git-send-email-joro@8bytes.org> References: <1523892323-14741-1-git-send-email-joro@8bytes.org> X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: =?utf-8?q?1597916937714331009?= X-GMAIL-MSGID: =?utf-8?q?1597916937714331009?= 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 3a319fd..2f04d6e 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 @@ -399,9 +399,9 @@ 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) @@ -606,6 +606,11 @@ restore_all: */ 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