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 X-Spam-Level: X-Spam-Status: No, score=-10.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3BAD2C433F5 for ; Thu, 9 Sep 2021 02:05:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0E29761100 for ; Thu, 9 Sep 2021 02:05:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1349651AbhIICGI (ORCPT ); Wed, 8 Sep 2021 22:06:08 -0400 Received: from mout.gmx.net ([212.227.17.22]:37021 "EHLO mout.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236229AbhIICGH (ORCPT ); Wed, 8 Sep 2021 22:06:07 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gmx.net; s=badeba3b8450; t=1631153084; bh=POceC1FTQmESqnUrjAaTs015lLoQrENM3QfVM5zUiEY=; h=X-UI-Sender-Class:Date:From:To:Cc:Subject:References:In-Reply-To; b=M17jXpSJbd9tzXyajx/mBRpMIZ185GgGKYsfdzIUaWC4gYkbv0+1ZV488RH3zXEJ+ F5q3lk4TC/an6KHITQ3vm+ctJgF0PcrqqPxQTj6wGxFAIU1CBMoXbHJ2STX3Yu6HQv P2Go81Jw8Cr/AQCUaji3X6H/bgz54EPj1cDB7dt0= X-UI-Sender-Class: 01bb95c1-4bf8-414a-932a-4f6e2808ef9c Received: from ls3530 ([80.187.121.129]) by mail.gmx.net (mrgmx104 [212.227.17.168]) with ESMTPSA (Nemesis) id 1Mg6Zq-1msXxa1iKU-00hccE; Thu, 09 Sep 2021 04:04:44 +0200 Date: Thu, 9 Sep 2021 04:03:06 +0200 From: Helge Deller To: Arnd Bergmann Cc: Helge Deller , Parisc List , James Bottomley , John David Anglin , Christoph Hellwig Subject: Re: [PATCH 1/4] parisc: Drop strnlen_user() in favour of generic version Message-ID: References: <20210908204405.127665-1-deller@gmx.de> <97d4c69c-59ff-8e28-0cfe-50908b999729@gmx.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Provags-ID: V03:K1:6HO/VeMvWaAP+To7gHUfXhFaYV4KrZsF9V6IrkQH0eov+8Mf+v1 FY0CYG4/6MFrgHKZU7gUBfSGViiFQqArcczS4KnmcQNCRKfkxUDX3QvR4elFcCbsN4ac6sS o7Cs+CPp+2B0whhIC6w43mQUBHdKiFN/+JvhfyRDNFOoT8tRd+o6PPVyNiFuVv3t1/NgxSL TXKEXnEscFDOpTOy2mFVw== X-UI-Out-Filterresults: notjunk:1;V03:K0:7rrvBUejlJk=:nZ6p5hJTBSi9MKUpUHOUBS XsWhPMO0E8ZoY5h1Lj1ZvdGBtNlTMxq5YHqPBWpGKdgbC2xFt3m8zSBH/oO3UP6kmjr/QGaXQ CMmsQEWceepdO7CQFphu4B0CbQsMi2RbYsHOQjffffmnKMjthmIlYagxooI2dv5sU4b194Zax yZU5PU7saQAV1Euw4A1GJamIZDtdE+gKH2KFNOqcuQUtbhrNYPwhvPqXf4ZPe7nancEidB8mW KBuc0L1bDLlTUOplt5uYQdBlCLn+s1mOQeKQktZ1xIyhtQqm7rbfDlMkymf+KC4LxsWdgF1cQ fCTV0/4S/kKbuLuV/bTg9bDEmF/bbNp8acwXN66e/Ca3SzesIwI9KKJYfBWwb/0H2lKnsuMHh ZCWXIcGvhEdnAhAZ2w7kj46BOsurPkF0fDi3S7/yODYmpstK53MZGAq3yshDEBG/D7IPNpRBr saLiH0htFdTEmPJhlNYS7WFoJxb8t2UcD9LzjfbyvFJukryBq7qr3vefumwuX2o8ueVi9mb7T VnQgQ731SNzyZ+hCqSIPSiNY9Uktq0Uk1V4meeOH8zMz9de7QoNWocmE3T3oQh3qthiWOzaSp 5PER2T3Xsc8OYIprmuc6aAcBUE5zvqHhSBl13KCRdQTzRmE9qp/wn68Yc8NH+BtZLVSoTLpEX W8kNzvK8yvV4JkEc8X+tuG/JILk+u0zd+aa/Cwg91cGKM/J7jj22BFDJHO2lHBatpmJcpmEaH PyfCzYh04YzWvDty3sYtC4WHAGrMV0HXUnZjpO/37Z0UwVeBTBUwnxIEPzH26rmRkfX1nP6FX bvf6fb9a8HWnC2RffVN32l2QtPYlinVbsT11h2YI3KhQrT/TFUkDTMBFlDnXqWuAzWb9Uan+r vgk7nfagb5G3RghNZ5GqpM0PxE9dBjnsXo8xIQvGfYNQkGTL6M4tKt5sRUn3brWtRviPGTVlp denXMUBLKu1+RfmzL7SDHRDO30OuGK5B6YAN59lSvjWZOUrfbmEbPmofaTXKu/p8VdYioghy/ xgtu19EomczraNincp4DpPTmy3OYq77I6FP5vEeEsYJyWgqxKgF6qs/NhCyGljw+zJpxcfwd9 Fotx8R3nB2DAI0= Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-parisc@vger.kernel.org * Arnd Bergmann : > On Wed, Sep 8, 2021 at 11:40 PM Helge Deller wrote: > > On 9/8/21 11:26 PM, Arnd Bergmann wrote: > > >> /* > > >> * Complex access routines -- macros > > >> */ > > >> -#define user_addr_max() (~0UL) > > >> +#define user_addr_max() (uaccess_kernel() ? ~0UL : TASK_SIZE) > > > > I noticed that our user_addr_max() was actually wrong. > > It's used in the generic strnlen_user() so fixing it seemed appropriat= e. > > The user_addr_max() definition should match what you do in access_ok() > for USER_DS though, which is a nop on architectures that have split user > address space, so I think the ~0UL was correct here. > > No matter what the arguments are, there is no danger of spilling over > into kernel space, which is what the user_addr_max() check is trying > to prevent on other architectures. > > > > We are getting very close to completely removing set_fs()/get_fs(), > > > uaccess_kernel() and some related bits from the kernel, so I think > > > it would be better to the other way here and finish off removing > > > CONFIG_SET_FS from parisc. > > > > > > I think this will also simplify your asm/uaccess.h a lot, in particu= lar > > > since it has separate address spaces for __get_user() and > > > __get_kernel_nofault(), and without set_fs() you can leave out > > > the runtime conditional to switch between them. > > > > That's a good idea and should probably be done. > > Do you have some pointers where to start, e.g. initial commits from ot= her arches ? > > Russell just merged my series for arch/arm in linux-5.15, you > can look at that but it's probably easier for parisc. > > I think the only part you need to add is __get_kernel_nofault() > and __put_kernel_nofault(). You can see in mm/maccess.c > what the difference between the two versions in there is. > > Once you have those, you define HAVE_GET_KERNEL_NOFAULT > and then remove CONFIG_SET_FS, set_fs(), get_fs(), load_sr2(), > thread_info->addr_limit, KERNEL_DS, and USER_DS. Thanks for those hints! The attached initial patch below seems to work, it boots into systemd. It needs further cleanups though. I wonder if you should add a workaround for 32-bit kernels to not copy 64bit-wise, see my patch below in copy_from_kernel_nofault(): - copy_from_kernel_nofault_loop(dst, src, size, u64, Efault); + /* avoid 64-bit accesses on 32-bit platforms */ + if (sizeof(unsigned long) > 4) + copy_from_kernel_nofault_loop(dst, src, size, u64, Efault)= ; Helge =2D-- [PATCH] parisc: Implement __get/put_kernel_nofault() Add __get_kernel_nofault() and __put_kernel_nofault(), define HAVE_GET_KERNEL_NOFAULT and remove CONFIG_SET_FS, set_fs(), get_fs(), load_sr2(), thread_info->addr_limit, KERNEL_DS, and USER_DS. Signed-off-by: Helge Deller Suggested-by: Arnd Bergmann diff --git a/arch/parisc/Kconfig b/arch/parisc/Kconfig index 3ae71994399c..b5bc346d464a 100644 =2D-- a/arch/parisc/Kconfig +++ b/arch/parisc/Kconfig @@ -64,7 +64,6 @@ config PARISC select HAVE_KPROBES_ON_FTRACE select HAVE_DYNAMIC_FTRACE_WITH_REGS select HAVE_SOFTIRQ_ON_OWN_STACK if IRQSTACKS - select SET_FS help The PA-RISC microprocessor is designed by Hewlett-Packard and used diff --git a/arch/parisc/include/asm/processor.h b/arch/parisc/include/asm= /processor.h index b5fbcd2c1780..eeb7da064289 100644 =2D-- a/arch/parisc/include/asm/processor.h +++ b/arch/parisc/include/asm/processor.h @@ -101,10 +101,6 @@ DECLARE_PER_CPU(struct cpuinfo_parisc, cpu_data); #define CPU_HVERSION ((boot_cpu_data.hversion >> 4) & 0x0FFF) -typedef struct { - int seg; -} mm_segment_t; - #define ARCH_MIN_TASKALIGN 8 struct thread_struct { diff --git a/arch/parisc/include/asm/thread_info.h b/arch/parisc/include/a= sm/thread_info.h index 0bd38a972cea..00ad50fef769 100644 =2D-- a/arch/parisc/include/asm/thread_info.h +++ b/arch/parisc/include/asm/thread_info.h @@ -11,7 +11,6 @@ struct thread_info { struct task_struct *task; /* main task structure */ unsigned long flags; /* thread_info flags (see TIF_*) */ - mm_segment_t addr_limit; /* user-level address space limit */ __u32 cpu; /* current CPU */ int preempt_count; /* 0=3Dpremptable, <0=3DBUG; will also serve as bh-c= ounter */ }; @@ -21,7 +20,6 @@ struct thread_info { .task =3D &tsk, \ .flags =3D 0, \ .cpu =3D 0, \ - .addr_limit =3D KERNEL_DS, \ .preempt_count =3D INIT_PREEMPT_COUNT, \ } diff --git a/arch/parisc/include/asm/uaccess.h b/arch/parisc/include/asm/u= access.h index a4368731f2b4..6e0ca7756ceb 100644 =2D-- a/arch/parisc/include/asm/uaccess.h +++ b/arch/parisc/include/asm/uaccess.h @@ -11,14 +11,6 @@ #include #include -#define KERNEL_DS ((mm_segment_t){0}) -#define USER_DS ((mm_segment_t){1}) - -#define uaccess_kernel() (get_fs().seg =3D=3D KERNEL_DS.seg) - -#define get_fs() (current_thread_info()->addr_limit) -#define set_fs(x) (current_thread_info()->addr_limit =3D (x)) - /* * Note that since kernel addresses are in a separate address space on * parisc, we don't need to do anything for access_ok(). @@ -33,11 +25,11 @@ #define get_user __get_user #if !defined(CONFIG_64BIT) -#define LDD_USER(val, ptr) __get_user_asm64(val, ptr) -#define STD_USER(x, ptr) __put_user_asm64(x, ptr) +#define LDD_USER(sr, val, ptr, err_label) __get_user_asm64(sr, val, ptr, = err_label) +#define STD_USER(sr, x, ptr, err_label) __put_user_asm64(sr, x, ptr, err= _label) #else -#define LDD_USER(val, ptr) __get_user_asm(val, "ldd", ptr) -#define STD_USER(x, ptr) __put_user_asm("std", x, ptr) +#define LDD_USER(sr, val, ptr, err_label) __get_user_asm(sr, val, "ldd", = ptr, err_label) +#define STD_USER(sr, x, ptr, err_label) __put_user_asm(sr, "std", x, ptr= , err_label) #endif /* @@ -67,28 +59,15 @@ struct exception_table_entry { #define ASM_EXCEPTIONTABLE_ENTRY_EFAULT( fault_addr, except_addr )\ ASM_EXCEPTIONTABLE_ENTRY( fault_addr, except_addr + 1) -/* - * load_sr2() preloads the space register %%sr2 - based on the value of - * get_fs() - with either a value of 0 to access kernel space (KERNEL_DS = which - * is 0), or with the current value of %%sr3 to access user space (USER_D= S) - * memory. The following __get_user_asm() and __put_user_asm() functions = have - * %%sr2 hard-coded to access the requested memory. - */ -#define load_sr2() \ - __asm__(" or,=3D %0,%%r0,%%r0\n\t" \ - " mfsp %%sr3,%0\n\t" \ - " mtsp %0,%%sr2\n\t" \ - : : "r"(get_fs()) : ) - -#define __get_user_internal(val, ptr) \ +#define __get_user_internal(sr, val, ptr, err_label) \ ({ \ register long __gu_err __asm__ ("r8") =3D 0; \ \ switch (sizeof(*(ptr))) { \ - case 1: __get_user_asm(val, "ldb", ptr); break; \ - case 2: __get_user_asm(val, "ldh", ptr); break; \ - case 4: __get_user_asm(val, "ldw", ptr); break; \ - case 8: LDD_USER(val, ptr); break; \ + case 1: __get_user_asm(sr, val, "ldb", ptr, err_label); break; \ + case 2: __get_user_asm(sr, val, "ldh", ptr, err_label); break; \ + case 4: __get_user_asm(sr, val, "ldw", ptr, err_label); break; \ + case 8: LDD_USER(sr, val, ptr, err_label); break; \ default: BUILD_BUG(); \ } \ \ @@ -97,26 +76,38 @@ struct exception_table_entry { #define __get_user(val, ptr) \ ({ \ - load_sr2(); \ - __get_user_internal(val, ptr); \ + __get_user_internal("%%sr3,", val, ptr, 9b); \ }) -#define __get_user_asm(val, ldx, ptr) \ +#define __get_user_asm(sr, val, ldx, ptr, err_label) \ { \ register long __gu_val; \ \ - __asm__("1: " ldx " 0(%%sr2,%2),%0\n" \ + __asm__("1: " ldx " 0(" sr "%2),%0\n" \ "9:\n" \ - ASM_EXCEPTIONTABLE_ENTRY_EFAULT(1b, 9b) \ + ASM_EXCEPTIONTABLE_ENTRY_EFAULT(1b, err_label) \ : "=3Dr"(__gu_val), "=3Dr"(__gu_err) \ : "r"(ptr), "1"(__gu_err)); \ \ (val) =3D (__force __typeof__(*(ptr))) __gu_val; \ } +#define HAVE_GET_KERNEL_NOFAULT +#define __get_kernel_nofault(dst, src, type, err_label) \ +{ \ + type __z; \ + long __err; \ + __err =3D __get_user_internal("", __z, (type *)(src), 9b); \ + if (unlikely(__err)) \ + goto err_label; \ + else \ + *(type *)(dst) =3D __z; \ +} + + #if !defined(CONFIG_64BIT) -#define __get_user_asm64(val, ptr) \ +#define __get_user_asm64(sr, val, ptr, err_label) \ { \ union { \ unsigned long long l; \ @@ -124,11 +115,11 @@ struct exception_table_entry { } __gu_tmp; \ \ __asm__(" copy %%r0,%R0\n" \ - "1: ldw 0(%%sr2,%2),%0\n" \ - "2: ldw 4(%%sr2,%2),%R0\n" \ + "1: ldw 0(" sr "%2),%0\n" \ + "2: ldw 4(" sr "%2),%R0\n" \ "9:\n" \ - ASM_EXCEPTIONTABLE_ENTRY_EFAULT(1b, 9b) \ - ASM_EXCEPTIONTABLE_ENTRY_EFAULT(2b, 9b) \ + ASM_EXCEPTIONTABLE_ENTRY_EFAULT(1b, err_label) \ + ASM_EXCEPTIONTABLE_ENTRY_EFAULT(2b, err_label) \ : "=3D&r"(__gu_tmp.l), "=3Dr"(__gu_err) \ : "r"(ptr), "1"(__gu_err)); \ \ @@ -138,16 +129,16 @@ struct exception_table_entry { #endif /* !defined(CONFIG_64BIT) */ -#define __put_user_internal(x, ptr) \ +#define __put_user_internal(sr, x, ptr, err_label) \ ({ \ register long __pu_err __asm__ ("r8") =3D 0; \ __typeof__(*(ptr)) __x =3D (__typeof__(*(ptr)))(x); \ \ switch (sizeof(*(ptr))) { \ - case 1: __put_user_asm("stb", __x, ptr); break; \ - case 2: __put_user_asm("sth", __x, ptr); break; \ - case 4: __put_user_asm("stw", __x, ptr); break; \ - case 8: STD_USER(__x, ptr); break; \ + case 1: __put_user_asm(sr, "stb", __x, ptr, err_label); break; \ + case 2: __put_user_asm(sr, "sth", __x, ptr, err_label); break; \ + case 4: __put_user_asm(sr, "stw", __x, ptr, err_label); break; \ + case 8: STD_USER(sr, __x, ptr, err_label); break; \ default: BUILD_BUG(); \ } \ \ @@ -156,10 +147,20 @@ struct exception_table_entry { #define __put_user(x, ptr) \ ({ \ - load_sr2(); \ - __put_user_internal(x, ptr); \ + __put_user_internal("%%sr3,", x, ptr, 9b); \ }) +#define __put_kernel_nofault(dst, src, type, err_label) \ +{ \ + type __z =3D *(type *)(src); \ + long __err; \ + __err =3D __put_user_internal("", __z, (type *)(dst), 9b);\ + if (unlikely(__err)) \ + goto err_label; \ +} + + + /* * The "__put_user/kernel_asm()" macros tell gcc they read from memory @@ -170,26 +171,26 @@ struct exception_table_entry { * r8 is already listed as err. */ -#define __put_user_asm(stx, x, ptr) \ - __asm__ __volatile__ ( \ - "1: " stx " %2,0(%%sr2,%1)\n" \ - "9:\n" \ - ASM_EXCEPTIONTABLE_ENTRY_EFAULT(1b, 9b) \ - : "=3Dr"(__pu_err) \ +#define __put_user_asm(sr, stx, x, ptr, err_label) \ + __asm__ __volatile__ ( \ + "1: " stx " %2,0(" sr "%1)\n" \ + "9:\n" \ + ASM_EXCEPTIONTABLE_ENTRY_EFAULT(1b, err_label) \ + : "=3Dr"(__pu_err) \ : "r"(ptr), "r"(x), "0"(__pu_err)) #if !defined(CONFIG_64BIT) -#define __put_user_asm64(__val, ptr) do { \ - __asm__ __volatile__ ( \ - "1: stw %2,0(%%sr2,%1)\n" \ - "2: stw %R2,4(%%sr2,%1)\n" \ - "9:\n" \ - ASM_EXCEPTIONTABLE_ENTRY_EFAULT(1b, 9b) \ - ASM_EXCEPTIONTABLE_ENTRY_EFAULT(2b, 9b) \ - : "=3Dr"(__pu_err) \ - : "r"(ptr), "r"(__val), "0"(__pu_err)); \ +#define __put_user_asm64(sr, __val, ptr, err_label) do { \ + __asm__ __volatile__ ( \ + "1: stw %2,0(" sr "%1)\n" \ + "2: stw %R2,4(" sr "%1)\n" \ + "9:\n" \ + ASM_EXCEPTIONTABLE_ENTRY_EFAULT(1b, err_label) \ + ASM_EXCEPTIONTABLE_ENTRY_EFAULT(2b, err_label) \ + : "=3Dr"(__pu_err) \ + : "r"(ptr), "r"(__val), "0"(__pu_err)); \ } while (0) #endif /* !defined(CONFIG_64BIT) */ @@ -205,7 +206,6 @@ extern __must_check long strnlen_user(const char __use= r *src, long n); /* * Complex access routines -- macros */ -#define user_addr_max() (~0UL) #define clear_user lclear_user #define __clear_user lclear_user diff --git a/arch/parisc/kernel/asm-offsets.c b/arch/parisc/kernel/asm-off= sets.c index 33113ba24054..7c83915e4aed 100644 =2D-- a/arch/parisc/kernel/asm-offsets.c +++ b/arch/parisc/kernel/asm-offsets.c @@ -230,7 +230,7 @@ int main(void) DEFINE(TI_TASK, offsetof(struct thread_info, task)); DEFINE(TI_FLAGS, offsetof(struct thread_info, flags)); DEFINE(TI_CPU, offsetof(struct thread_info, cpu)); - DEFINE(TI_SEGMENT, offsetof(struct thread_info, addr_limit)); +// DEFINE(TI_SEGMENT, offsetof(struct thread_info, addr_limit)); DEFINE(TI_PRE_COUNT, offsetof(struct thread_info, preempt_count)); DEFINE(THREAD_SZ, sizeof(struct thread_info)); /* THREAD_SZ_ALGN includes space for a stack frame. */ diff --git a/arch/parisc/lib/lusercopy.S b/arch/parisc/lib/lusercopy.S index 0aad5ce89f4d..29eafd963ac0 100644 =2D-- a/arch/parisc/lib/lusercopy.S +++ b/arch/parisc/lib/lusercopy.S @@ -34,11 +34,11 @@ */ .macro get_sr - mfctl %cr30,%r1 - ldw TI_SEGMENT(%r1),%r22 +// mfctl %cr30,%r1 +// ldw TI_SEGMENT(%r1),%r22 mfsp %sr3,%r1 - or,<> %r22,%r0,%r0 - copy %r0,%r1 +// or,<> %r22,%r0,%r0 +// copy %r0,%r1 mtsp %r1,%sr1 .endm diff --git a/mm/maccess.c b/mm/maccess.c index 3bd70405f2d8..85eb86d6cab4 100644 =2D-- a/mm/maccess.c +++ b/mm/maccess.c @@ -28,7 +28,9 @@ long copy_from_kernel_nofault(void *dst, const void *src= , size_t size) return -ERANGE; pagefault_disable(); - copy_from_kernel_nofault_loop(dst, src, size, u64, Efault); + /* avoid 64-bit accesses on 32-bit platforms */ + if (sizeof(unsigned long) > 4) + copy_from_kernel_nofault_loop(dst, src, size, u64, Efault); copy_from_kernel_nofault_loop(dst, src, size, u32, Efault); copy_from_kernel_nofault_loop(dst, src, size, u16, Efault); copy_from_kernel_nofault_loop(dst, src, size, u8, Efault); @@ -51,7 +53,9 @@ EXPORT_SYMBOL_GPL(copy_from_kernel_nofault); long copy_to_kernel_nofault(void *dst, const void *src, size_t size) { pagefault_disable(); - copy_to_kernel_nofault_loop(dst, src, size, u64, Efault); + /* avoid 64-bit accesses on 32-bit platforms */ + if (sizeof(unsigned long) > 4) + copy_to_kernel_nofault_loop(dst, src, size, u64, Efault); copy_to_kernel_nofault_loop(dst, src, size, u32, Efault); copy_to_kernel_nofault_loop(dst, src, size, u16, Efault); copy_to_kernel_nofault_loop(dst, src, size, u8, Efault);