From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id BD9EAC04A68 for ; Wed, 27 Jul 2022 17:18:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231206AbiG0RSa (ORCPT ); Wed, 27 Jul 2022 13:18:30 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33524 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234942AbiG0RR7 (ORCPT ); Wed, 27 Jul 2022 13:17:59 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2268B7969C; Wed, 27 Jul 2022 09:43:38 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id A87E1601C0; Wed, 27 Jul 2022 16:43:37 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id B5324C433B5; Wed, 27 Jul 2022 16:43:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1658940217; bh=Wb98pt5vbxzdyRZeVuY7M2SeMywrValO8GqXhGqdCnQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=RzXDZLB20+/82n6gHRx3h6RvIGZ/wCJtDu3guT8/jqbXNyatPmJhFSAgmI5vDh2S1 JAxdyg/AH3n7rv/50koem9rKEtj57ENUh5daGJBdwV+BqAVv880gLrh6FgKaabpxcw /L+pZR0ZJ3G60OOX0NVKCgI/ou7onjCKGzHtpEds= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, "Peter Zijlstra (Intel)" , Josh Poimboeuf , Sasha Levin Subject: [PATCH 5.15 147/201] x86/entry_32: Remove .fixup usage Date: Wed, 27 Jul 2022 18:10:51 +0200 Message-Id: <20220727161033.918279310@linuxfoundation.org> X-Mailer: git-send-email 2.37.1 In-Reply-To: <20220727161026.977588183@linuxfoundation.org> References: <20220727161026.977588183@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Peter Zijlstra [ Upstream commit aa93e2ad7464ffb90155a5ffdde963816f86d5dc ] Where possible, push the .fixup into code, at the tail of functions. This is hard for macros since they're used in multiple functions, therefore introduce a new extable handler to pop zeros. Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Josh Poimboeuf Link: https://lore.kernel.org/r/20211110101325.245184699@infradead.org Signed-off-by: Sasha Levin --- arch/x86/entry/entry_32.S | 28 +++++++--------------- arch/x86/include/asm/extable_fixup_types.h | 2 ++ arch/x86/mm/extable.c | 14 +++++++++++ 3 files changed, 24 insertions(+), 20 deletions(-) diff --git a/arch/x86/entry/entry_32.S b/arch/x86/entry/entry_32.S index 5bd3baf36d87..2cba70f9753b 100644 --- a/arch/x86/entry/entry_32.S +++ b/arch/x86/entry/entry_32.S @@ -270,17 +270,9 @@ 3: popl %fs addl $(4 + \pop), %esp /* pop the unused "gs" slot */ IRET_FRAME -.pushsection .fixup, "ax" -4: movl $0, (%esp) - jmp 1b -5: movl $0, (%esp) - jmp 2b -6: movl $0, (%esp) - jmp 3b -.popsection - _ASM_EXTABLE(1b, 4b) - _ASM_EXTABLE(2b, 5b) - _ASM_EXTABLE(3b, 6b) + _ASM_EXTABLE_TYPE(1b, 1b, EX_TYPE_POP_ZERO) + _ASM_EXTABLE_TYPE(2b, 2b, EX_TYPE_POP_ZERO) + _ASM_EXTABLE_TYPE(3b, 3b, EX_TYPE_POP_ZERO) .endm .macro RESTORE_ALL_NMI cr3_reg:req pop=0 @@ -923,10 +915,8 @@ SYM_FUNC_START(entry_SYSENTER_32) sti sysexit -.pushsection .fixup, "ax" -2: movl $0, PT_FS(%esp) - jmp 1b -.popsection +2: movl $0, PT_FS(%esp) + jmp 1b _ASM_EXTABLE(1b, 2b) .Lsysenter_fix_flags: @@ -994,8 +984,7 @@ restore_all_switch_stack: */ iret -.section .fixup, "ax" -SYM_CODE_START(asm_iret_error) +.Lasm_iret_error: pushl $0 # no error code pushl $iret_error @@ -1012,9 +1001,8 @@ SYM_CODE_START(asm_iret_error) #endif jmp handle_exception -SYM_CODE_END(asm_iret_error) -.previous - _ASM_EXTABLE(.Lirq_return, asm_iret_error) + + _ASM_EXTABLE(.Lirq_return, .Lasm_iret_error) SYM_FUNC_END(entry_INT80_32) .macro FIXUP_ESPFIX_STACK diff --git a/arch/x86/include/asm/extable_fixup_types.h b/arch/x86/include/asm/extable_fixup_types.h index 409524d5d2eb..4d709a2768bb 100644 --- a/arch/x86/include/asm/extable_fixup_types.h +++ b/arch/x86/include/asm/extable_fixup_types.h @@ -19,4 +19,6 @@ #define EX_TYPE_DEFAULT_MCE_SAFE 12 #define EX_TYPE_FAULT_MCE_SAFE 13 +#define EX_TYPE_POP_ZERO 14 + #endif diff --git a/arch/x86/mm/extable.c b/arch/x86/mm/extable.c index f37e290e6d0a..f59a4d017070 100644 --- a/arch/x86/mm/extable.c +++ b/arch/x86/mm/extable.c @@ -99,6 +99,18 @@ static bool ex_handler_clear_fs(const struct exception_table_entry *fixup, return ex_handler_default(fixup, regs); } +static bool ex_handler_pop_zero(const struct exception_table_entry *fixup, + struct pt_regs *regs) +{ + /* + * Typically used for when "pop %seg" traps, in which case we'll clear + * the stack slot and re-try the instruction, which will then succeed + * to pop zero. + */ + *((unsigned long *)regs->sp) = 0; + return ex_handler_default(fixup, regs); +} + int ex_get_fixup_type(unsigned long ip) { const struct exception_table_entry *e = search_exception_tables(ip); @@ -156,6 +168,8 @@ int fixup_exception(struct pt_regs *regs, int trapnr, unsigned long error_code, case EX_TYPE_WRMSR_IN_MCE: ex_handler_msr_mce(regs, true); break; + case EX_TYPE_POP_ZERO: + return ex_handler_pop_zero(e, regs); } BUG(); } -- 2.35.1