From: David Miller <davem@davemloft.net> To: ynorov@caviumnetworks.com Cc: arnd@arndb.de, catalin.marinas@arm.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-arch@vger.kernel.org, linux-s390@vger.kernel.org, libc-alpha@sourceware.org, schwidefsky@de.ibm.com, heiko.carstens@de.ibm.com, pinskia@gmail.com, broonie@kernel.org, joseph@codesourcery.com, christoph.muellner@theobroma-systems.com, bamvor.zhangjian@huawei.com, szabolcs.nagy@arm.com, klimov.linux@gmail.com, Nathan_Lynch@mentor.com, agraf@suse.de, Prasun.Kapoor@caviumnetworks.com, kilobyte@angband.pl, geert@linux-m68k.org, philipp.tomsich@theobroma-systems.com Subject: Re: [PATCH 01/23] all: syscall wrappers: add documentation Date: Wed, 25 May 2016 13:21:45 -0700 (PDT) [thread overview] Message-ID: <20160525.132145.1271448744307448631.davem@davemloft.net> (raw) In-Reply-To: <20160525200327.GA22395@yury-N73SV> From: Yury Norov <ynorov@caviumnetworks.com> Date: Wed, 25 May 2016 23:03:27 +0300 > On Wed, May 25, 2016 at 12:30:17PM -0700, David Miller wrote: >> From: Yury Norov <ynorov@caviumnetworks.com> >> Date: Tue, 24 May 2016 03:04:30 +0300 >> >> > +To clear that top halves, automatic wrappers are introduced. They clear all >> > +required registers before passing control to regular syscall handler. >> >> Why have one of these for every single compat system call, rather than >> simply clearing the top half of all of these registers unconditionally >> in the 32-bit system call trap before the system call is invoked? >> >> That's what we do on sparc64. >> >> And with that, you only need wrappers for the case where there needs >> to be proper sign extention of a 32-bit signed argument. > > It was discussed as one of possible solutions. The downside of it is > that we cannot pass 64-bit types (like off_t) in single register. Wrappers can be added for the cases where you'd like to do that. > The other downside is that we clear top halves for every single > syscall, and it looks excessive. So, from spark64 and s390 approaches > we choosed second. It's like 4 cpu cycles even on crappy sparc64 cpus which only dual issue. :) And that's a pretty low cost for the benefits if you ask me.
WARNING: multiple messages have this Message-ID (diff)
From: davem@davemloft.net (David Miller) To: linux-arm-kernel@lists.infradead.org Subject: [PATCH 01/23] all: syscall wrappers: add documentation Date: Wed, 25 May 2016 13:21:45 -0700 (PDT) [thread overview] Message-ID: <20160525.132145.1271448744307448631.davem@davemloft.net> (raw) In-Reply-To: <20160525200327.GA22395@yury-N73SV> From: Yury Norov <ynorov@caviumnetworks.com> Date: Wed, 25 May 2016 23:03:27 +0300 > On Wed, May 25, 2016 at 12:30:17PM -0700, David Miller wrote: >> From: Yury Norov <ynorov@caviumnetworks.com> >> Date: Tue, 24 May 2016 03:04:30 +0300 >> >> > +To clear that top halves, automatic wrappers are introduced. They clear all >> > +required registers before passing control to regular syscall handler. >> >> Why have one of these for every single compat system call, rather than >> simply clearing the top half of all of these registers unconditionally >> in the 32-bit system call trap before the system call is invoked? >> >> That's what we do on sparc64. >> >> And with that, you only need wrappers for the case where there needs >> to be proper sign extention of a 32-bit signed argument. > > It was discussed as one of possible solutions. The downside of it is > that we cannot pass 64-bit types (like off_t) in single register. Wrappers can be added for the cases where you'd like to do that. > The other downside is that we clear top halves for every single > syscall, and it looks excessive. So, from spark64 and s390 approaches > we choosed second. It's like 4 cpu cycles even on crappy sparc64 cpus which only dual issue. :) And that's a pretty low cost for the benefits if you ask me.
next prev parent reply other threads:[~2016-05-25 20:21 UTC|newest] Thread overview: 207+ messages / expand[flat|nested] mbox.gz Atom feed top 2016-05-24 0:04 [PATCH v6 00/21] ILP32 for ARM64 Yury Norov 2016-05-24 0:04 ` Yury Norov 2016-05-24 0:04 ` Yury Norov 2016-05-24 0:04 ` [PATCH 01/23] all: syscall wrappers: add documentation Yury Norov 2016-05-24 0:04 ` Yury Norov 2016-05-24 0:04 ` Yury Norov 2016-05-25 19:30 ` David Miller 2016-05-25 19:30 ` David Miller 2016-05-25 20:03 ` Yury Norov 2016-05-25 20:03 ` Yury Norov 2016-05-25 20:03 ` Yury Norov 2016-05-25 20:21 ` David Miller [this message] 2016-05-25 20:21 ` David Miller 2016-05-25 20:47 ` Arnd Bergmann 2016-05-25 20:47 ` Arnd Bergmann 2016-05-25 20:50 ` David Miller 2016-05-25 20:50 ` David Miller 2016-05-25 21:01 ` Arnd Bergmann 2016-05-25 21:01 ` Arnd Bergmann 2016-05-25 21:28 ` David Miller 2016-05-25 21:28 ` David Miller 2016-05-26 14:20 ` Catalin Marinas 2016-05-26 14:20 ` Catalin Marinas 2016-05-26 14:50 ` Szabolcs Nagy 2016-05-26 14:50 ` Szabolcs Nagy 2016-05-26 14:50 ` Szabolcs Nagy 2016-05-26 15:19 ` Catalin Marinas 2016-05-26 15:19 ` Catalin Marinas 2016-05-26 19:43 ` David Miller 2016-05-26 19:43 ` David Miller 2016-05-27 10:10 ` Catalin Marinas 2016-05-27 10:10 ` Catalin Marinas 2016-05-26 20:48 ` Yury Norov 2016-05-26 20:48 ` Yury Norov 2016-05-26 20:48 ` Yury Norov 2016-05-26 22:29 ` Catalin Marinas 2016-05-26 22:29 ` Catalin Marinas 2016-05-27 0:37 ` Yury Norov 2016-05-27 0:37 ` Yury Norov 2016-05-27 0:37 ` Yury Norov 2016-05-27 6:03 ` Heiko Carstens 2016-05-27 6:03 ` Heiko Carstens 2016-05-27 8:42 ` Arnd Bergmann 2016-05-27 8:42 ` Arnd Bergmann 2016-05-27 9:30 ` Catalin Marinas 2016-05-27 9:30 ` Catalin Marinas 2016-05-27 10:49 ` Arnd Bergmann 2016-05-27 10:49 ` Arnd Bergmann 2016-05-27 13:04 ` Catalin Marinas 2016-05-27 13:04 ` Catalin Marinas 2016-05-27 16:58 ` Yury Norov 2016-05-27 16:58 ` Yury Norov 2016-05-27 16:58 ` Yury Norov 2016-05-27 17:36 ` Catalin Marinas 2016-05-27 17:36 ` Catalin Marinas 2016-05-27 9:01 ` Catalin Marinas 2016-05-27 9:01 ` Catalin Marinas 2016-06-14 23:08 ` Yury Norov 2016-06-14 23:08 ` Yury Norov 2016-06-14 23:08 ` Yury Norov 2016-05-27 5:52 ` Heiko Carstens 2016-05-27 5:52 ` Heiko Carstens 2016-05-24 0:04 ` [PATCH 02/23] all: introduce COMPAT_WRAPPER option and enable it for s390 Yury Norov 2016-05-24 0:04 ` Yury Norov 2016-05-24 0:04 ` Yury Norov 2016-05-24 0:04 ` Yury Norov 2016-05-24 0:04 ` [PATCH 03/23] all: s390: move wrapper infrastructure to generic headers Yury Norov 2016-05-24 0:04 ` Yury Norov 2016-05-24 0:04 ` Yury Norov 2016-05-24 0:04 ` [PATCH 04/23] all: s390: move compat_wrappers.c from arch/s390/kernel to kernel/ Yury Norov 2016-05-24 0:04 ` Yury Norov 2016-05-24 0:04 ` Yury Norov 2016-05-24 0:04 ` Yury Norov 2016-05-24 0:04 ` [PATCH 05/23] all: wrap needed syscalls in generic unistd Yury Norov 2016-05-24 0:04 ` Yury Norov 2016-05-24 0:04 ` Yury Norov 2016-05-24 0:04 ` Yury Norov 2016-05-24 0:04 ` [PATCH 06/23] compat ABI: use non-compat openat and open_by_handle_at variants Yury Norov 2016-05-24 0:04 ` Yury Norov 2016-05-24 0:04 ` Yury Norov 2016-05-24 0:04 ` [PATCH 07/23] 32-bit ABI: introduce ARCH_32BIT_OFF_T config option Yury Norov 2016-05-24 0:04 ` Yury Norov 2016-05-24 0:04 ` Yury Norov 2016-05-24 0:04 ` Yury Norov 2016-05-24 0:04 ` [PATCH 08/23] arm64: ilp32: add documentation on the ILP32 ABI for ARM64 Yury Norov 2016-05-24 0:04 ` Yury Norov 2016-05-24 0:04 ` Yury Norov 2016-05-24 0:04 ` [PATCH 09/23] arm64: ensure the kernel is compiled for LP64 Yury Norov 2016-05-24 0:04 ` Yury Norov 2016-05-24 0:04 ` Yury Norov 2016-05-24 0:04 ` [PATCH 10/23] arm64: rename COMPAT to AARCH32_EL0 in Kconfig Yury Norov 2016-05-24 0:04 ` Yury Norov 2016-05-24 0:04 ` Yury Norov 2016-05-24 0:04 ` Yury Norov 2016-05-24 0:04 ` [PATCH 11/23] arm64:uapi: set __BITS_PER_LONG correctly for ILP32 and LP64 Yury Norov 2016-05-24 0:04 ` Yury Norov 2016-05-24 0:04 ` Yury Norov 2016-05-24 0:04 ` [PATCH 12/23] thread: move thread bits accessors to separated file Yury Norov 2016-05-24 0:04 ` Yury Norov 2016-05-24 0:04 ` Yury Norov 2016-05-24 0:04 ` [PATCH 13/23] arm64: introduce is_a32_task and is_a32_thread (for AArch32 compat) Yury Norov 2016-05-24 0:04 ` Yury Norov 2016-05-24 0:04 ` Yury Norov 2016-05-24 0:04 ` Yury Norov 2016-06-12 12:21 ` Zhangjian (Bamvor) 2016-06-12 12:21 ` Zhangjian (Bamvor) 2016-06-12 12:21 ` Zhangjian (Bamvor) 2016-06-12 13:08 ` Zhangjian (Bamvor) 2016-06-12 13:08 ` Zhangjian (Bamvor) 2016-06-12 13:08 ` Zhangjian (Bamvor) 2016-06-12 17:56 ` Yury Norov 2016-06-12 17:56 ` Yury Norov 2016-06-12 17:56 ` Yury Norov 2016-05-24 0:04 ` [PATCH 14/23] arm64: ilp32: add is_ilp32_compat_{task,thread} and TIF_32BIT_AARCH64 Yury Norov 2016-05-24 0:04 ` [PATCH 14/23] arm64: ilp32: add is_ilp32_compat_{task, thread} " Yury Norov 2016-05-24 0:04 ` [PATCH 14/23] arm64: ilp32: add is_ilp32_compat_{task,thread} " Yury Norov 2016-05-24 0:04 ` [PATCH 15/23] arm64: introduce binfmt_elf32.c Yury Norov 2016-05-24 0:04 ` Yury Norov 2016-05-24 0:04 ` Yury Norov 2016-05-24 0:04 ` Yury Norov 2016-05-24 0:04 ` [PATCH 16/23] arm64: ilp32: introduce binfmt_ilp32.c Yury Norov 2016-05-24 0:04 ` Yury Norov 2016-05-24 0:04 ` Yury Norov 2016-05-26 13:49 ` Zhangjian (Bamvor) 2016-05-26 13:49 ` Zhangjian (Bamvor) 2016-05-26 13:49 ` Zhangjian (Bamvor) 2016-05-26 21:08 ` Yury Norov 2016-05-26 21:08 ` Yury Norov 2016-05-26 21:08 ` Yury Norov 2016-06-15 0:40 ` Yury Norov 2016-06-15 0:40 ` Yury Norov 2016-06-15 0:40 ` Yury Norov 2016-06-13 3:05 ` Zhangjian (Bamvor) 2016-06-13 3:05 ` Zhangjian (Bamvor) 2016-06-13 3:05 ` Zhangjian (Bamvor) 2016-06-13 13:22 ` Zhangjian (Bamvor) 2016-06-13 13:22 ` Zhangjian (Bamvor) 2016-06-13 13:22 ` Zhangjian (Bamvor) 2016-05-24 0:04 ` [PATCH 17/23] arm64: ptrace: handle ptrace_request differently for aarch32 and ilp32 Yury Norov 2016-05-24 0:04 ` Yury Norov 2016-05-24 0:04 ` Yury Norov 2016-05-24 0:04 ` Yury Norov 2016-06-08 1:34 ` zhouchengming 2016-06-08 1:34 ` zhouchengming 2016-06-08 1:34 ` zhouchengming 2016-06-08 17:00 ` Yury Norov 2016-06-08 17:00 ` Yury Norov 2016-06-08 17:00 ` Yury Norov 2016-06-25 9:36 ` zhouchengming 2016-06-25 9:36 ` zhouchengming 2016-06-25 9:36 ` zhouchengming 2016-06-25 14:15 ` Bamvor Zhang 2016-06-25 14:15 ` Bamvor Zhang 2016-06-27 2:09 ` zhouchengming 2016-06-27 2:09 ` zhouchengming 2016-06-27 2:09 ` zhouchengming 2016-05-24 0:04 ` [PATCH 18/23] arm64: ilp32: add sys_ilp32.c and a separate table (in entry.S) to use it Yury Norov 2016-05-24 0:04 ` Yury Norov 2016-05-24 0:04 ` Yury Norov 2016-05-25 20:26 ` Arnd Bergmann 2016-05-25 20:26 ` Arnd Bergmann 2016-05-24 0:04 ` [PATCH 19/23] arm64: signal: share lp64 signal routines to ilp32 Yury Norov 2016-05-24 0:04 ` Yury Norov 2016-05-24 0:04 ` Yury Norov 2016-05-24 0:04 ` [PATCH 20/23] arm64: signal32: move ilp32 and aarch32 common code to separated file Yury Norov 2016-05-24 0:04 ` Yury Norov 2016-05-24 0:04 ` Yury Norov 2016-05-24 0:04 ` [PATCH 21/23] arm64: ilp32: introduce ilp32-specific handlers for sigframe and ucontext Yury Norov 2016-05-24 0:04 ` Yury Norov 2016-05-24 0:04 ` Yury Norov 2016-06-04 11:34 ` Zhangjian (Bamvor) 2016-06-04 11:34 ` Zhangjian (Bamvor) 2016-06-04 11:34 ` Zhangjian (Bamvor) 2016-06-12 12:34 ` Zhangjian (Bamvor) 2016-06-12 12:34 ` Zhangjian (Bamvor) 2016-06-12 12:34 ` Zhangjian (Bamvor) 2016-06-12 13:12 ` Zhangjian (Bamvor) 2016-06-12 13:12 ` Zhangjian (Bamvor) 2016-06-12 13:12 ` Zhangjian (Bamvor) 2016-06-12 17:44 ` Yury Norov 2016-06-12 17:44 ` Yury Norov 2016-06-12 17:44 ` Yury Norov 2016-06-16 11:21 ` Zhangjian (Bamvor) 2016-06-16 11:21 ` Zhangjian (Bamvor) 2016-06-16 11:21 ` Zhangjian (Bamvor) 2016-06-12 12:39 ` Zhangjian (Bamvor) 2016-06-12 12:39 ` Zhangjian (Bamvor) 2016-06-12 12:39 ` Zhangjian (Bamvor) 2016-05-24 0:04 ` [PATCH 22/23] arm64:ilp32: add vdso-ilp32 and use for signal return Yury Norov 2016-05-24 0:04 ` Yury Norov 2016-05-24 0:04 ` Yury Norov 2016-05-24 0:04 ` [PATCH 23/23] arm64:ilp32: add ARM64_ILP32 to Kconfig Yury Norov 2016-05-24 0:04 ` Yury Norov 2016-05-24 0:04 ` Yury Norov 2016-05-25 10:42 ` [PATCH v6 00/21] ILP32 for ARM64 Szabolcs Nagy 2016-05-25 10:42 ` Szabolcs Nagy 2016-05-25 10:42 ` Szabolcs Nagy 2016-05-25 16:41 ` Yury Norov 2016-05-25 16:41 ` Yury Norov 2016-05-25 16:41 ` Yury Norov 2016-06-02 19:03 ` Yury Norov 2016-06-02 19:03 ` Yury Norov 2016-06-02 19:03 ` Yury Norov 2016-06-02 19:03 ` Yury Norov 2016-06-03 11:02 ` Szabolcs Nagy 2016-06-03 11:02 ` Szabolcs Nagy 2016-06-03 11:02 ` Szabolcs Nagy
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