From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752488AbeDFRMk (ORCPT ); Fri, 6 Apr 2018 13:12:40 -0400 Received: from terminus.zytor.com ([198.137.202.136]:35225 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751613AbeDFRMi (ORCPT ); Fri, 6 Apr 2018 13:12:38 -0400 Date: Fri, 6 Apr 2018 10:11:54 -0700 From: tip-bot for Dominik Brodowski Message-ID: Cc: linux-kernel@vger.kernel.org, linux@dominikbrodowski.net, bp@alien8.de, jpoimboe@redhat.com, dvlasenk@redhat.com, tglx@linutronix.de, viro@zeniv.linux.org.uk, mingo@kernel.org, peterz@infradead.org, akpm@linux-foundation.org, hpa@zytor.com, luto@kernel.org, torvalds@linux-foundation.org, brgerst@gmail.com Reply-To: torvalds@linux-foundation.org, luto@kernel.org, brgerst@gmail.com, viro@zeniv.linux.org.uk, tglx@linutronix.de, dvlasenk@redhat.com, jpoimboe@redhat.com, linux-kernel@vger.kernel.org, bp@alien8.de, linux@dominikbrodowski.net, mingo@kernel.org, hpa@zytor.com, akpm@linux-foundation.org, peterz@infradead.org In-Reply-To: <20180405095307.3730-5-linux@dominikbrodowski.net> References: <20180405095307.3730-5-linux@dominikbrodowski.net> To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/asm] syscalls/core: Prepare CONFIG_ARCH_HAS_SYSCALL_WRAPPER=y for compat syscalls Git-Commit-ID: 7303e30ec1d8fb5ca1f07c92d069241c32b2ee1b X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 7303e30ec1d8fb5ca1f07c92d069241c32b2ee1b Gitweb: https://git.kernel.org/tip/7303e30ec1d8fb5ca1f07c92d069241c32b2ee1b Author: Dominik Brodowski AuthorDate: Thu, 5 Apr 2018 11:53:03 +0200 Committer: Ingo Molnar CommitDate: Thu, 5 Apr 2018 16:59:38 +0200 syscalls/core: Prepare CONFIG_ARCH_HAS_SYSCALL_WRAPPER=y for compat syscalls It may be useful for an architecture to override the definitions of the COMPAT_SYSCALL_DEFINE0() and __COMPAT_SYSCALL_DEFINEx() macros in , in particular to use a different calling convention for syscalls. This patch provides a mechanism to do so, based on the previously introduced CONFIG_ARCH_HAS_SYSCALL_WRAPPER. If it is enabled, is included in and may be used to define the macros mentioned above. Moreover, as the syscall calling convention may be different if CONFIG_ARCH_HAS_SYSCALL_WRAPPER is set, the compat syscall function prototypes in are #ifndef'd out in that case. As some of the syscalls and/or compat syscalls may not be present, the COND_SYSCALL() and COND_SYSCALL_COMPAT() macros in kernel/sys_ni.c as well as the SYS_NI() and COMPAT_SYS_NI() macros in kernel/time/posix-stubs.c can be re-defined in iff CONFIG_ARCH_HAS_SYSCALL_WRAPPER is enabled. Signed-off-by: Dominik Brodowski Acked-by: Linus Torvalds Cc: Al Viro Cc: Andrew Morton Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Josh Poimboeuf Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/20180405095307.3730-5-linux@dominikbrodowski.net Signed-off-by: Ingo Molnar --- include/linux/compat.h | 22 ++++++++++++++++++++++ init/Kconfig | 9 ++++++--- kernel/sys_ni.c | 10 ++++++++++ kernel/time/posix-stubs.c | 10 ++++++++++ 4 files changed, 48 insertions(+), 3 deletions(-) diff --git a/include/linux/compat.h b/include/linux/compat.h index 9847c5a013c3..2d85ec5cfda2 100644 --- a/include/linux/compat.h +++ b/include/linux/compat.h @@ -24,6 +24,17 @@ #include #include +#ifdef CONFIG_ARCH_HAS_SYSCALL_WRAPPER +/* + * It may be useful for an architecture to override the definitions of the + * COMPAT_SYSCALL_DEFINE0 and COMPAT_SYSCALL_DEFINEx() macros, in particular + * to use a different calling convention for syscalls. To allow for that, + + the prototypes for the compat_sys_*() functions below will *not* be included + * if CONFIG_ARCH_HAS_SYSCALL_WRAPPER is enabled. + */ +#include +#endif /* CONFIG_ARCH_HAS_SYSCALL_WRAPPER */ + #ifndef COMPAT_USE_64BIT_TIME #define COMPAT_USE_64BIT_TIME 0 #endif @@ -32,10 +43,12 @@ #define __SC_DELOUSE(t,v) ((__force t)(unsigned long)(v)) #endif +#ifndef COMPAT_SYSCALL_DEFINE0 #define COMPAT_SYSCALL_DEFINE0(name) \ asmlinkage long compat_sys_##name(void); \ ALLOW_ERROR_INJECTION(compat_sys_##name, ERRNO); \ asmlinkage long compat_sys_##name(void) +#endif /* COMPAT_SYSCALL_DEFINE0 */ #define COMPAT_SYSCALL_DEFINE1(name, ...) \ COMPAT_SYSCALL_DEFINEx(1, _##name, __VA_ARGS__) @@ -50,6 +63,7 @@ #define COMPAT_SYSCALL_DEFINE6(name, ...) \ COMPAT_SYSCALL_DEFINEx(6, _##name, __VA_ARGS__) +#ifndef COMPAT_SYSCALL_DEFINEx #define COMPAT_SYSCALL_DEFINEx(x, name, ...) \ asmlinkage long compat_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__));\ asmlinkage long compat_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__))\ @@ -62,6 +76,7 @@ return C_SYSC##name(__MAP(x,__SC_DELOUSE,__VA_ARGS__)); \ } \ static inline long C_SYSC##name(__MAP(x,__SC_DECL,__VA_ARGS__)) +#endif /* COMPAT_SYSCALL_DEFINEx */ #ifndef compat_user_stack_pointer #define compat_user_stack_pointer() current_user_stack_pointer() @@ -517,7 +532,12 @@ int __compat_save_altstack(compat_stack_t __user *, unsigned long); * Please note that these prototypes here are only provided for information * purposes, for static analysis, and for linking from the syscall table. * These functions should not be called elsewhere from kernel code. + * + * As the syscall calling convention may be different from the default + * for architectures overriding the syscall calling convention, do not + * include the prototypes if CONFIG_ARCH_HAS_SYSCALL_WRAPPER is enabled. */ +#ifndef CONFIG_ARCH_HAS_SYSCALL_WRAPPER asmlinkage long compat_sys_io_setup(unsigned nr_reqs, u32 __user *ctx32p); asmlinkage long compat_sys_io_submit(compat_aio_context_t ctx_id, int nr, u32 __user *iocb); @@ -955,6 +975,8 @@ asmlinkage long compat_sys_stime(compat_time_t __user *tptr); /* obsolete: net/socket.c */ asmlinkage long compat_sys_socketcall(int call, u32 __user *args); +#endif /* CONFIG_ARCH_HAS_SYSCALL_WRAPPER */ + /* * For most but not all architectures, "am I in a compat syscall?" and diff --git a/init/Kconfig b/init/Kconfig index 068eb6c3bbf7..2dbc88051bde 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -1925,8 +1925,11 @@ config ARCH_HAS_SYNC_CORE_BEFORE_USERMODE bool # It may be useful for an architecture to override the definitions of the -# SYSCALL_DEFINE() and __SYSCALL_DEFINEx() macros in , -# in particular to use a different calling convention for syscalls. +# SYSCALL_DEFINE() and __SYSCALL_DEFINEx() macros in +# and the COMPAT_ variants in , in particular to use a +# different calling convention for syscalls. They can also override the +# macros for not-implemented syscalls in kernel/sys_ni.c and +# kernel/time/posix-stubs.c. All these overrides need to be available in +# . config ARCH_HAS_SYSCALL_WRAPPER def_bool n - depends on !COMPAT diff --git a/kernel/sys_ni.c b/kernel/sys_ni.c index 6cafc008f6db..9791364925dc 100644 --- a/kernel/sys_ni.c +++ b/kernel/sys_ni.c @@ -5,6 +5,11 @@ #include +#ifdef CONFIG_ARCH_HAS_SYSCALL_WRAPPER +/* Architectures may override COND_SYSCALL and COND_SYSCALL_COMPAT */ +#include +#endif /* CONFIG_ARCH_HAS_SYSCALL_WRAPPER */ + /* we can't #include here, but tell gcc to not warn with -Wmissing-prototypes */ asmlinkage long sys_ni_syscall(void); @@ -17,8 +22,13 @@ asmlinkage long sys_ni_syscall(void) return -ENOSYS; } +#ifndef COND_SYSCALL #define COND_SYSCALL(name) cond_syscall(sys_##name) +#endif /* COND_SYSCALL */ + +#ifndef COND_SYSCALL_COMPAT #define COND_SYSCALL_COMPAT(name) cond_syscall(compat_sys_##name) +#endif /* COND_SYSCALL_COMPAT */ /* * This list is kept in the same order as include/uapi/asm-generic/unistd.h. diff --git a/kernel/time/posix-stubs.c b/kernel/time/posix-stubs.c index b258bee13b02..69a937c3cd81 100644 --- a/kernel/time/posix-stubs.c +++ b/kernel/time/posix-stubs.c @@ -19,6 +19,11 @@ #include #include +#ifdef CONFIG_ARCH_HAS_SYSCALL_WRAPPER +/* Architectures may override SYS_NI and COMPAT_SYS_NI */ +#include +#endif + asmlinkage long sys_ni_posix_timers(void) { pr_err_once("process %d (%s) attempted a POSIX timer syscall " @@ -27,8 +32,13 @@ asmlinkage long sys_ni_posix_timers(void) return -ENOSYS; } +#ifndef SYS_NI #define SYS_NI(name) SYSCALL_ALIAS(sys_##name, sys_ni_posix_timers) +#endif + +#ifndef COMPAT_SYS_NI #define COMPAT_SYS_NI(name) SYSCALL_ALIAS(compat_sys_##name, sys_ni_posix_timers) +#endif SYS_NI(timer_create); SYS_NI(timer_gettime);