From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753482AbdIFVhI (ORCPT ); Wed, 6 Sep 2017 17:37:08 -0400 Received: from mail.kernel.org ([198.145.29.99]:50122 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753338AbdIFVhG (ORCPT ); Wed, 6 Sep 2017 17:37:06 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E8FF821BF5 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=luto@kernel.org From: Andy Lutomirski To: x86@kernel.org Cc: linux-kernel@vger.kernel.org, Borislav Petkov , Brian Gerst , Andrew Cooper , Juergen Gross , Boris Ostrovsky , Kees Cook , Andy Lutomirski Subject: [RFC 02/17] x86/asm/64: Split the iret-to-user and iret-to-kernel paths Date: Wed, 6 Sep 2017 14:36:47 -0700 Message-Id: <7dfe73f228cc904460715552fa2ab5707f4b49fd.1504733277.git.luto@kernel.org> X-Mailer: git-send-email 2.13.5 In-Reply-To: References: In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org These code paths will diverge soon. Signed-off-by: Andy Lutomirski --- arch/x86/entry/entry_64.S | 20 +++++++++++--------- arch/x86/entry/entry_64_compat.S | 2 +- arch/x86/kernel/head_64.S | 2 +- 3 files changed, 13 insertions(+), 11 deletions(-) diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S index a0ebeeb9d12f..34156d50c3d6 100644 --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -315,7 +315,7 @@ syscall_return_via_sysret: opportunistic_sysret_failed: SWAPGS - jmp restore_regs_and_iret + jmp restore_regs_and_return_to_usermode END(entry_SYSCALL_64) ENTRY(stub_ptregs_64) @@ -412,7 +412,7 @@ ENTRY(ret_from_fork) call syscall_return_slowpath /* returns with IRQs disabled */ TRACE_IRQS_ON /* user mode is traced as IRQS on */ SWAPGS - jmp restore_regs_and_iret + jmp restore_regs_and_return_to_usermode 1: /* kernel thread */ @@ -524,7 +524,13 @@ GLOBAL(retint_user) call prepare_exit_to_usermode TRACE_IRQS_IRETQ SWAPGS - jmp restore_regs_and_iret + +GLOBAL(restore_regs_and_return_to_usermode) + RESTORE_EXTRA_REGS + RESTORE_C_REGS + REMOVE_PT_GPREGS_FROM_STACK 8 + INTERRUPT_RETURN + /* Returning to kernel space */ retint_kernel: @@ -544,11 +550,7 @@ retint_kernel: */ TRACE_IRQS_IRETQ -/* - * At this label, code paths which return to kernel and to user, - * which come from interrupts/exception and from syscalls, merge. - */ -GLOBAL(restore_regs_and_iret) +GLOBAL(restore_regs_and_return_to_kernel) RESTORE_EXTRA_REGS RESTORE_C_REGS REMOVE_PT_GPREGS_FROM_STACK 8 @@ -1264,7 +1266,7 @@ ENTRY(nmi) * work, because we don't want to enable interrupts. */ SWAPGS - jmp restore_regs_and_iret + jmp restore_regs_and_return_to_usermode .Lnmi_from_kernel: /* diff --git a/arch/x86/entry/entry_64_compat.S b/arch/x86/entry/entry_64_compat.S index 5314d7b8e5ad..e4ab8ffa94b1 100644 --- a/arch/x86/entry/entry_64_compat.S +++ b/arch/x86/entry/entry_64_compat.S @@ -338,7 +338,7 @@ ENTRY(entry_INT80_compat) /* Go back to user mode. */ TRACE_IRQS_ON SWAPGS - jmp restore_regs_and_iret + jmp restore_regs_and_return_to_usermode END(entry_INT80_compat) ALIGN diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S index 6225550883df..63fa56ead56e 100644 --- a/arch/x86/kernel/head_64.S +++ b/arch/x86/kernel/head_64.S @@ -310,7 +310,7 @@ early_idt_handler_common: 20: decl early_recursion_flag(%rip) - jmp restore_regs_and_iret + jmp restore_regs_and_return_to_kernel ENDPROC(early_idt_handler_common) __INITDATA -- 2.13.5