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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id BB44BC433FE for ; Wed, 20 Apr 2022 02:45:44 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 514816B0078; Tue, 19 Apr 2022 22:45:43 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 44F406B007B; Tue, 19 Apr 2022 22:45:43 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 29FFE6B007D; Tue, 19 Apr 2022 22:45:43 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0193.hostedemail.com [216.40.44.193]) by kanga.kvack.org (Postfix) with ESMTP id 191B26B0078 for ; Tue, 19 Apr 2022 22:45:43 -0400 (EDT) Received: from smtpin30.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id AF8C2182EDF32 for ; Wed, 20 Apr 2022 02:45:42 +0000 (UTC) X-FDA: 79375716924.30.FD2C114 Received: from szxga08-in.huawei.com (szxga08-in.huawei.com [45.249.212.255]) by imf12.hostedemail.com (Postfix) with ESMTP id CE4664000A for ; Wed, 20 Apr 2022 02:45:39 +0000 (UTC) Received: from kwepemi500010.china.huawei.com (unknown [172.30.72.55]) by szxga08-in.huawei.com (SkyGuard) with ESMTP id 4KjlPy48wYz1J9nm; Wed, 20 Apr 2022 10:44:54 +0800 (CST) Received: from kwepemm600017.china.huawei.com (7.193.23.234) by kwepemi500010.china.huawei.com (7.221.188.191) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Wed, 20 Apr 2022 10:45:38 +0800 Received: from localhost.localdomain (10.175.112.125) by kwepemm600017.china.huawei.com (7.193.23.234) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Wed, 20 Apr 2022 10:45:37 +0800 From: Tong Tiangen To: Mark Rutland , James Morse , Andrew Morton , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Robin Murphy , Dave Hansen , Catalin Marinas , Will Deacon , Alexander Viro , Michael Ellerman , Benjamin Herrenschmidt , Paul Mackerras , , "H . Peter Anvin" CC: , , , , Kefeng Wang , Xie XiuQi , Guohanjun , Tong Tiangen Subject: [PATCH -next v4 4/7] arm64: add copy_{to, from}_user to machine check safe Date: Wed, 20 Apr 2022 03:04:15 +0000 Message-ID: <20220420030418.3189040-5-tongtiangen@huawei.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20220420030418.3189040-1-tongtiangen@huawei.com> References: <20220420030418.3189040-1-tongtiangen@huawei.com> MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.175.112.125] X-ClientProxiedBy: dggems706-chm.china.huawei.com (10.3.19.183) To kwepemm600017.china.huawei.com (7.193.23.234) X-CFilter-Loop: Reflected X-Stat-Signature: dc6hafcedfyye9y9t5exyge1tyfwai1a X-Rspam-User: Authentication-Results: imf12.hostedemail.com; dkim=none; dmarc=pass (policy=quarantine) header.from=huawei.com; spf=pass (imf12.hostedemail.com: domain of tongtiangen@huawei.com designates 45.249.212.255 as permitted sender) smtp.mailfrom=tongtiangen@huawei.com X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: CE4664000A X-HE-Tag: 1650422739-406143 Content-Transfer-Encoding: quoted-printable X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Add copy_{to, from}_user() to machine check safe. If copy fail due to hardware memory error, only the relevant processes ar= e affected, so killing the user process and isolate the user page with hardware memory errors is a more reasonable choice than kernel panic. Add new extable type EX_TYPE_UACCESS_MC which can be used for uaccess tha= t can be recovered from hardware memory errors. The x16 register is used to save the fixup type in copy_xxx_user which used extable type EX_TYPE_UACCESS_MC. Signed-off-by: Tong Tiangen --- arch/arm64/include/asm/asm-extable.h | 14 ++++++++++++++ arch/arm64/include/asm/asm-uaccess.h | 15 ++++++++++----- arch/arm64/lib/copy_from_user.S | 18 +++++++++++------- arch/arm64/lib/copy_to_user.S | 18 +++++++++++------- arch/arm64/mm/extable.c | 18 ++++++++++++++---- 5 files changed, 60 insertions(+), 23 deletions(-) diff --git a/arch/arm64/include/asm/asm-extable.h b/arch/arm64/include/as= m/asm-extable.h index c39f2437e08e..75b2c00e9523 100644 --- a/arch/arm64/include/asm/asm-extable.h +++ b/arch/arm64/include/asm/asm-extable.h @@ -2,12 +2,18 @@ #ifndef __ASM_ASM_EXTABLE_H #define __ASM_ASM_EXTABLE_H =20 +#define FIXUP_TYPE_NORMAL 0 +#define FIXUP_TYPE_MC 1 + #define EX_TYPE_NONE 0 #define EX_TYPE_FIXUP 1 #define EX_TYPE_BPF 2 #define EX_TYPE_UACCESS_ERR_ZERO 3 #define EX_TYPE_LOAD_UNALIGNED_ZEROPAD 4 =20 +/* _MC indicates that can fixup from machine check errors */ +#define EX_TYPE_UACCESS_MC 5 + #ifdef __ASSEMBLY__ =20 #define __ASM_EXTABLE_RAW(insn, fixup, type, data) \ @@ -27,6 +33,14 @@ __ASM_EXTABLE_RAW(\insn, \fixup, EX_TYPE_FIXUP, 0) .endm =20 +/* + * Create an exception table entry for `insn`, which will branch to `fix= up` + * when an unhandled fault(include sea fault) is taken. + */ + .macro _asm_extable_uaccess_mc, insn, fixup + __ASM_EXTABLE_RAW(\insn, \fixup, EX_TYPE_UACCESS_MC, 0) + .endm + /* * Create an exception table entry for `insn` if `fixup` is provided. Ot= herwise * do nothing. diff --git a/arch/arm64/include/asm/asm-uaccess.h b/arch/arm64/include/as= m/asm-uaccess.h index 0557af834e03..6c23c138e1fc 100644 --- a/arch/arm64/include/asm/asm-uaccess.h +++ b/arch/arm64/include/asm/asm-uaccess.h @@ -63,6 +63,11 @@ alternative_else_nop_endif 9999: x; \ _asm_extable 9999b, l =20 + +#define USER_MC(l, x...) \ +9999: x; \ + _asm_extable_uaccess_mc 9999b, l + /* * Generate the assembly for LDTR/STTR with exception table entries. * This is complicated as there is no post-increment or pair versions of= the @@ -73,8 +78,8 @@ alternative_else_nop_endif 8889: ldtr \reg2, [\addr, #8]; add \addr, \addr, \post_inc; =20 - _asm_extable 8888b,\l; - _asm_extable 8889b,\l; + _asm_extable_uaccess_mc 8888b, \l; + _asm_extable_uaccess_mc 8889b, \l; .endm =20 .macro user_stp l, reg1, reg2, addr, post_inc @@ -82,14 +87,14 @@ alternative_else_nop_endif 8889: sttr \reg2, [\addr, #8]; add \addr, \addr, \post_inc; =20 - _asm_extable 8888b,\l; - _asm_extable 8889b,\l; + _asm_extable_uaccess_mc 8888b,\l; + _asm_extable_uaccess_mc 8889b,\l; .endm =20 .macro user_ldst l, inst, reg, addr, post_inc 8888: \inst \reg, [\addr]; add \addr, \addr, \post_inc; =20 - _asm_extable 8888b,\l; + _asm_extable_uaccess_mc 8888b, \l; .endm #endif diff --git a/arch/arm64/lib/copy_from_user.S b/arch/arm64/lib/copy_from_u= ser.S index 34e317907524..480cc5ac0a8d 100644 --- a/arch/arm64/lib/copy_from_user.S +++ b/arch/arm64/lib/copy_from_user.S @@ -25,7 +25,7 @@ .endm =20 .macro strb1 reg, ptr, val - strb \reg, [\ptr], \val + USER_MC(9998f, strb \reg, [\ptr], \val) .endm =20 .macro ldrh1 reg, ptr, val @@ -33,7 +33,7 @@ .endm =20 .macro strh1 reg, ptr, val - strh \reg, [\ptr], \val + USER_MC(9998f, strh \reg, [\ptr], \val) .endm =20 .macro ldr1 reg, ptr, val @@ -41,7 +41,7 @@ .endm =20 .macro str1 reg, ptr, val - str \reg, [\ptr], \val + USER_MC(9998f, str \reg, [\ptr], \val) .endm =20 .macro ldp1 reg1, reg2, ptr, val @@ -49,11 +49,12 @@ .endm =20 .macro stp1 reg1, reg2, ptr, val - stp \reg1, \reg2, [\ptr], \val + USER_MC(9998f, stp \reg1, \reg2, [\ptr], \val) .endm =20 -end .req x5 -srcin .req x15 +end .req x5 +srcin .req x15 +fixup_type .req x16 SYM_FUNC_START(__arch_copy_from_user) add end, x0, x2 mov srcin, x1 @@ -62,7 +63,10 @@ SYM_FUNC_START(__arch_copy_from_user) ret =20 // Exception fixups -9997: cmp dst, dstin + // x16: fixup type written by ex_handler_uaccess_mc +9997: cmp fixup_type, #FIXUP_TYPE_MC + b.eq 9998f + cmp dst, dstin b.ne 9998f // Before being absolutely sure we couldn't copy anything, try harder USER(9998f, ldtrb tmp1w, [srcin]) diff --git a/arch/arm64/lib/copy_to_user.S b/arch/arm64/lib/copy_to_user.= S index 802231772608..021a7d27b3a4 100644 --- a/arch/arm64/lib/copy_to_user.S +++ b/arch/arm64/lib/copy_to_user.S @@ -20,7 +20,7 @@ * x0 - bytes not copied */ .macro ldrb1 reg, ptr, val - ldrb \reg, [\ptr], \val + USER_MC(9998f, ldrb \reg, [\ptr], \val) .endm =20 .macro strb1 reg, ptr, val @@ -28,7 +28,7 @@ .endm =20 .macro ldrh1 reg, ptr, val - ldrh \reg, [\ptr], \val + USER_MC(9998f, ldrh \reg, [\ptr], \val) .endm =20 .macro strh1 reg, ptr, val @@ -36,7 +36,7 @@ .endm =20 .macro ldr1 reg, ptr, val - ldr \reg, [\ptr], \val + USER_MC(9998f, ldr \reg, [\ptr], \val) .endm =20 .macro str1 reg, ptr, val @@ -44,15 +44,16 @@ .endm =20 .macro ldp1 reg1, reg2, ptr, val - ldp \reg1, \reg2, [\ptr], \val + USER_MC(9998f, ldp \reg1, \reg2, [\ptr], \val) .endm =20 .macro stp1 reg1, reg2, ptr, val user_stp 9997f, \reg1, \reg2, \ptr, \val .endm =20 -end .req x5 -srcin .req x15 +end .req x5 +srcin .req x15 +fixup_type .req x16 SYM_FUNC_START(__arch_copy_to_user) add end, x0, x2 mov srcin, x1 @@ -61,7 +62,10 @@ SYM_FUNC_START(__arch_copy_to_user) ret =20 // Exception fixups -9997: cmp dst, dstin + // x16: fixup type written by ex_handler_uaccess_mc +9997: cmp fixup_type, #FIXUP_TYPE_MC + b.eq 9998f + cmp dst, dstin b.ne 9998f // Before being absolutely sure we couldn't copy anything, try harder ldrb tmp1w, [srcin] diff --git a/arch/arm64/mm/extable.c b/arch/arm64/mm/extable.c index 4f0083a550d4..525876c3ebf4 100644 --- a/arch/arm64/mm/extable.c +++ b/arch/arm64/mm/extable.c @@ -24,6 +24,14 @@ static bool ex_handler_fixup(const struct exception_ta= ble_entry *ex, return true; } =20 +static bool ex_handler_uaccess_type(const struct exception_table_entry *= ex, + struct pt_regs *regs, + unsigned long fixup_type) +{ + regs->regs[16] =3D fixup_type; + return ex_handler_fixup(ex, regs); +} + static bool ex_handler_uaccess_err_zero(const struct exception_table_ent= ry *ex, struct pt_regs *regs) { @@ -75,6 +83,8 @@ bool fixup_exception(struct pt_regs *regs) switch (ex->type) { case EX_TYPE_FIXUP: return ex_handler_fixup(ex, regs); + case EX_TYPE_UACCESS_MC: + return ex_handler_uaccess_type(ex, regs, FIXUP_TYPE_NORMAL); case EX_TYPE_BPF: return ex_handler_bpf(ex, regs); case EX_TYPE_UACCESS_ERR_ZERO: @@ -94,10 +104,10 @@ bool fixup_exception_mc(struct pt_regs *regs) if (!ex) return false; =20 - /* - * This is not complete, More Machine check safe extable type can - * be processed here. - */ + switch (ex->type) { + case EX_TYPE_UACCESS_MC: + return ex_handler_uaccess_type(ex, regs, FIXUP_TYPE_MC); + } =20 return false; } --=20 2.25.1