From: Yury Norov <ynorov@caviumnetworks.com> To: Arnd Bergmann <arnd@arndb.de> Cc: <catalin.marinas@arm.com>, <linux-arm-kernel@lists.infradead.org>, <linux-kernel@vger.kernel.org>, <pinskia@gmail.com>, <ddaney.cavm@gmail.com>, <jan.dakinevich@gmail.com>, <Prasun.Kapoor@caviumnetworks.com>, <christoph.muellner@theobroma-systems.com>, <philipp.tomsich@theobroma-systems.com>, <broonie@kernel.org>, <andrey.konovalov@linaro.org>, <Nathan_Lynch@mentor.com>, <agraf@suse.de>, <bamvor.zhangjian@huawei.com>, <klimov.linux@gmail.com>, <joseph@codesourcery.com>, <schwab@suse.de> Subject: Re: [PATCH v6 14/19] arm64:ilp32: add sys_ilp32.c and a separate table (in entry.S) to use it Date: Wed, 2 Dec 2015 02:35:03 +0300 [thread overview] Message-ID: <20151201233503.GA23156@yury-N73SV> (raw) In-Reply-To: <12844690.Yr8y3jA010@wuerfel> On Tue, Dec 01, 2015 at 11:39:42PM +0100, Arnd Bergmann wrote: > On Wednesday 02 December 2015 00:29:04 Yury Norov wrote: > > > > +#define compat_sys_shmat sys_shmat > > > > > > What's special about compat_sys_shmat? > > > > > > > It's about definition. > > For aarch32 glibc defines it as (__getpagesize () << 2). > > For ILP32 there's no definition, and so generic one is used: (__getpagesize ()). > > Ok, got it. > > > In kernel, for ARM64, COMPAT_SHMLBA defined just as 0x4000. Both > > compat and non-compat shmat syscalls pass identical arguments to > > do_shmat, except shmlba. Effectively, library expects shmlba to > > be 0x1000, as sys_shmat does. And compat_sys_shmat expects 0x4000. > > > > I think, both kernel and library parts are to be fixed. In library > > we'd use definition identical to ARM. For kernel we'd use compat > > syscall. > > I'm not sure I understand this part. What changes specifically do we need? > For kernel: diff --git a/arch/arm64/include/asm/shmparam.h b/arch/arm64/include/asm/shmparam.h index 4df608a..e368a55 100644 --- a/arch/arm64/include/asm/shmparam.h +++ b/arch/arm64/include/asm/shmparam.h @@ -21,7 +21,7 @@ * alignment value. Since we don't have aliasing D-caches, the rest of * the time we can safely use PAGE_SIZE. */ -#define COMPAT_SHMLBA 0x4000 +#define COMPAT_SHMLBA (4 * PAGE_SIZE) #include <asm-generic/shmparam.h> diff --git a/arch/arm64/kernel/sys_ilp32.c b/arch/arm64/kernel/sys_ilp32.c index c5bc712..877bedf 100644 --- a/arch/arm64/kernel/sys_ilp32.c +++ b/arch/arm64/kernel/sys_ilp32.c @@ -42,15 +42,12 @@ asmlinkage long sys_rt_sigreturn_wrapper(void); #define compat_sys_pwrite64 sys_pwrite64 #define compat_sys_readahead sys_readahead #define compat_sys_rt_sigaction sys_rt_sigaction -#define compat_sys_shmat sys_shmat #define compat_sys_sync_file_range sys_sync_file_range #define compat_sys_truncate64 sys_truncate #define compat_sys_sigaltstack sys_sigaltstack For library - just create a header in ilp32 directory that defines SHMLBA exactly as arm: __getpagesize () << 2 > It sounds like shmat is one of the cases we an override makes sense > and we should use sys_shmat with PAGE_SIZE for aarch64 ilp32 mode. > [...] > We normally assume that the page size on ARM is fixed to 4K, so > there might be user space that just hardcodes 16K SHMLBA It means that we should use compat_sys_shmat because hardcoded userspace may have a chance to work for 4K pages. If we'll use sys_shmat (and so 4K SHMLBA), we'll definitely make hardcoded userspace broken. Non-hardcoded userspace will work anyway. We can describe in documentation that 4k pages are prefferable. Yury
WARNING: multiple messages have this Message-ID (diff)
From: ynorov@caviumnetworks.com (Yury Norov) To: linux-arm-kernel@lists.infradead.org Subject: [PATCH v6 14/19] arm64:ilp32: add sys_ilp32.c and a separate table (in entry.S) to use it Date: Wed, 2 Dec 2015 02:35:03 +0300 [thread overview] Message-ID: <20151201233503.GA23156@yury-N73SV> (raw) In-Reply-To: <12844690.Yr8y3jA010@wuerfel> On Tue, Dec 01, 2015 at 11:39:42PM +0100, Arnd Bergmann wrote: > On Wednesday 02 December 2015 00:29:04 Yury Norov wrote: > > > > +#define compat_sys_shmat sys_shmat > > > > > > What's special about compat_sys_shmat? > > > > > > > It's about definition. > > For aarch32 glibc defines it as (__getpagesize () << 2). > > For ILP32 there's no definition, and so generic one is used: (__getpagesize ()). > > Ok, got it. > > > In kernel, for ARM64, COMPAT_SHMLBA defined just as 0x4000. Both > > compat and non-compat shmat syscalls pass identical arguments to > > do_shmat, except shmlba. Effectively, library expects shmlba to > > be 0x1000, as sys_shmat does. And compat_sys_shmat expects 0x4000. > > > > I think, both kernel and library parts are to be fixed. In library > > we'd use definition identical to ARM. For kernel we'd use compat > > syscall. > > I'm not sure I understand this part. What changes specifically do we need? > For kernel: diff --git a/arch/arm64/include/asm/shmparam.h b/arch/arm64/include/asm/shmparam.h index 4df608a..e368a55 100644 --- a/arch/arm64/include/asm/shmparam.h +++ b/arch/arm64/include/asm/shmparam.h @@ -21,7 +21,7 @@ * alignment value. Since we don't have aliasing D-caches, the rest of * the time we can safely use PAGE_SIZE. */ -#define COMPAT_SHMLBA 0x4000 +#define COMPAT_SHMLBA (4 * PAGE_SIZE) #include <asm-generic/shmparam.h> diff --git a/arch/arm64/kernel/sys_ilp32.c b/arch/arm64/kernel/sys_ilp32.c index c5bc712..877bedf 100644 --- a/arch/arm64/kernel/sys_ilp32.c +++ b/arch/arm64/kernel/sys_ilp32.c @@ -42,15 +42,12 @@ asmlinkage long sys_rt_sigreturn_wrapper(void); #define compat_sys_pwrite64 sys_pwrite64 #define compat_sys_readahead sys_readahead #define compat_sys_rt_sigaction sys_rt_sigaction -#define compat_sys_shmat sys_shmat #define compat_sys_sync_file_range sys_sync_file_range #define compat_sys_truncate64 sys_truncate #define compat_sys_sigaltstack sys_sigaltstack For library - just create a header in ilp32 directory that defines SHMLBA exactly as arm: __getpagesize () << 2 > It sounds like shmat is one of the cases we an override makes sense > and we should use sys_shmat with PAGE_SIZE for aarch64 ilp32 mode. > [...] > We normally assume that the page size on ARM is fixed to 4K, so > there might be user space that just hardcodes 16K SHMLBA It means that we should use compat_sys_shmat because hardcoded userspace may have a chance to work for 4K pages. If we'll use sys_shmat (and so 4K SHMLBA), we'll definitely make hardcoded userspace broken. Non-hardcoded userspace will work anyway. We can describe in documentation that 4k pages are prefferable. Yury
next prev parent reply other threads:[~2015-12-01 23:35 UTC|newest] Thread overview: 158+ messages / expand[flat|nested] mbox.gz Atom feed top 2015-11-17 21:16 [RFC2 PATCH v6 00/19] ILP32 for ARM64 Yury Norov 2015-11-17 21:16 ` Yury Norov 2015-11-17 21:16 ` [PATCH v6 01/19] arm64:ilp32: add documentation on the ILP32 ABI " Yury Norov 2015-11-17 21:16 ` Yury Norov 2015-11-18 8:09 ` Zhangjian (Bamvor) 2015-11-18 8:09 ` Zhangjian (Bamvor) 2015-11-17 21:16 ` [PATCH v6 02/19] arm64: ensure the kernel is compiled for LP64 Yury Norov 2015-11-17 21:16 ` Yury Norov 2015-11-17 21:16 ` [PATCH v6 03/19] arm64: rename COMPAT to AARCH32_EL0 in Kconfig Yury Norov 2015-11-17 21:16 ` Yury Norov 2015-11-17 21:16 ` [PATCH v6 04/19] arm64: change some CONFIG_COMPAT over to use CONFIG_AARCH32_EL0 instead Yury Norov 2015-11-17 21:16 ` Yury Norov 2015-12-03 12:02 ` Catalin Marinas 2015-12-03 12:02 ` Catalin Marinas 2015-12-04 21:58 ` Yury Norov 2015-12-04 21:58 ` Yury Norov 2015-11-17 21:16 ` [PATCH v6 05/19] arm64:uapi: set __BITS_PER_LONG correctly for ILP32 and LP64 Yury Norov 2015-11-17 21:16 ` Yury Norov 2015-12-03 11:31 ` Catalin Marinas 2015-12-03 11:31 ` Catalin Marinas 2015-12-03 11:36 ` Dr. Philipp Tomsich 2015-12-03 11:36 ` Dr. Philipp Tomsich 2015-11-17 21:16 ` [PATCH v6 06/19] arm64:ilp32: share signal structures between ILP32 and LP64 ABIs Yury Norov 2015-11-17 21:16 ` Yury Norov 2015-11-17 22:14 ` Arnd Bergmann 2015-11-17 22:14 ` Arnd Bergmann 2015-11-17 21:16 ` [PATCH v6 07/19] arm64: introduce is_a32_task and is_a32_thread (for AArch32 compat) Yury Norov 2015-11-17 21:16 ` Yury Norov 2015-12-03 12:13 ` Catalin Marinas 2015-12-03 12:13 ` Catalin Marinas 2015-12-04 17:05 ` Yury Norov 2015-12-04 17:05 ` Yury Norov 2015-12-05 11:00 ` Catalin Marinas 2015-12-05 11:00 ` Catalin Marinas 2015-11-17 21:16 ` [PATCH v6 08/19] arm64:ilp32: add is_ilp32_compat_{task,thread} and TIF_32BIT_AARCH64 Yury Norov 2015-11-17 21:16 ` [PATCH v6 08/19] arm64:ilp32: add is_ilp32_compat_{task, thread} " Yury Norov 2015-11-17 21:16 ` [PATCH v6 09/19] arm64:ilp32: share HWCAP between LP64 and ILP32 Yury Norov 2015-11-17 21:16 ` Yury Norov 2015-11-17 21:16 ` [PATCH v6 10/19] arm64:ilp32 use the native LP64 'start_thread' for ILP32 threads Yury Norov 2015-11-17 21:16 ` Yury Norov 2015-12-03 12:20 ` Catalin Marinas 2015-12-03 12:20 ` Catalin Marinas 2015-11-17 21:16 ` [PATCH v6 11/19] arm64:ilp32: support core dump generation for ILP32 Yury Norov 2015-11-17 21:16 ` Yury Norov 2015-12-03 16:39 ` Catalin Marinas 2015-12-03 16:39 ` Catalin Marinas 2015-11-17 21:16 ` [PATCH v6 12/19] ptrace: Allow compat to use the native siginfo Yury Norov 2015-11-17 21:16 ` Yury Norov 2015-11-17 21:16 ` [PATCH v6 13/19] arm64: ilp32: common 32-bit wrappers Yury Norov 2015-11-17 21:16 ` Yury Norov 2015-11-17 21:16 ` [PATCH v6 14/19] arm64:ilp32: add sys_ilp32.c and a separate table (in entry.S) to use it Yury Norov 2015-11-17 21:16 ` Yury Norov 2015-11-17 21:57 ` Arnd Bergmann 2015-11-17 21:57 ` Arnd Bergmann 2015-11-18 8:14 ` Arnd Bergmann 2015-11-18 8:14 ` Arnd Bergmann 2015-11-19 13:21 ` Andreas Schwab 2015-11-19 13:21 ` Andreas Schwab 2015-11-19 13:32 ` Arnd Bergmann 2015-11-19 13:32 ` Arnd Bergmann 2015-11-30 15:34 ` Arnd Bergmann 2015-11-30 15:34 ` Arnd Bergmann 2015-11-30 20:21 ` Yury Norov 2015-11-30 20:21 ` Yury Norov 2015-11-30 21:49 ` Arnd Bergmann 2015-11-30 21:49 ` Arnd Bergmann 2015-12-01 0:20 ` Andrew Pinski 2015-12-01 0:20 ` Andrew Pinski 2015-12-01 0:40 ` Yury Norov 2015-12-01 0:40 ` Yury Norov 2015-12-01 10:26 ` Arnd Bergmann 2015-12-01 10:26 ` Arnd Bergmann 2015-12-01 9:20 ` Andreas Schwab 2015-12-01 9:20 ` Andreas Schwab 2015-12-01 10:22 ` Arnd Bergmann 2015-12-01 10:22 ` Arnd Bergmann 2015-12-01 11:01 ` Andreas Schwab 2015-12-01 11:01 ` Andreas Schwab 2015-12-01 11:30 ` Arnd Bergmann 2015-12-01 11:30 ` Arnd Bergmann 2015-12-02 0:24 ` Yury Norov 2015-12-02 0:24 ` Yury Norov 2015-12-02 10:03 ` Arnd Bergmann 2015-12-02 10:03 ` Arnd Bergmann 2015-12-03 17:17 ` Catalin Marinas 2015-12-03 17:17 ` Catalin Marinas 2015-12-01 21:29 ` Yury Norov 2015-12-01 21:29 ` Yury Norov 2015-12-01 22:39 ` Arnd Bergmann 2015-12-01 22:39 ` Arnd Bergmann 2015-12-01 23:35 ` Yury Norov [this message] 2015-12-01 23:35 ` Yury Norov 2015-12-02 8:37 ` Arnd Bergmann 2015-12-02 8:37 ` Arnd Bergmann 2015-12-02 9:15 ` Yury Norov 2015-12-02 9:15 ` Yury Norov 2015-12-02 10:35 ` Yury Norov 2015-12-02 10:35 ` Yury Norov 2015-12-02 13:46 ` Arnd Bergmann 2015-12-02 13:46 ` Arnd Bergmann 2015-12-02 13:54 ` Arnd Bergmann 2015-12-02 13:54 ` Arnd Bergmann 2015-12-02 13:57 ` Will Deacon 2015-12-02 13:57 ` Will Deacon 2015-12-03 17:47 ` Catalin Marinas 2015-12-03 17:47 ` Catalin Marinas 2015-12-03 18:14 ` Yury Norov 2015-12-03 18:14 ` Yury Norov 2015-12-03 20:42 ` Arnd Bergmann 2015-12-03 20:42 ` Arnd Bergmann 2015-12-02 10:01 ` Yury Norov 2015-12-02 10:01 ` Yury Norov 2015-12-02 11:03 ` Arnd Bergmann 2015-12-02 11:03 ` Arnd Bergmann 2015-11-17 21:16 ` [PATCH v6 15/19] arm64: ilp32: force IPC_64 in msgctl, shmctl, semctl Yury Norov 2015-11-17 21:16 ` Yury Norov 2015-11-17 22:07 ` Arnd Bergmann 2015-11-17 22:07 ` Arnd Bergmann 2015-11-18 8:25 ` Andreas Schwab 2015-11-18 8:25 ` Andreas Schwab 2015-11-18 9:23 ` Arnd Bergmann 2015-11-18 9:23 ` Arnd Bergmann 2015-11-18 10:07 ` Geert Uytterhoeven 2015-11-18 10:07 ` Geert Uytterhoeven 2015-11-18 12:04 ` Arnd Bergmann 2015-11-18 12:04 ` Arnd Bergmann 2015-11-17 21:16 ` [PATCH v6 16/19] aarch64: ilp32: use generic stat64 structure Yury Norov 2015-11-17 21:16 ` Yury Norov 2015-11-17 22:09 ` Arnd Bergmann 2015-11-17 22:09 ` Arnd Bergmann 2015-11-18 20:36 ` Yury Norov 2015-11-18 20:36 ` Yury Norov 2015-11-18 20:45 ` Arnd Bergmann 2015-11-18 20:45 ` Arnd Bergmann 2015-11-17 21:16 ` [PATCH v6 17/19] arm64:ilp32: use the native siginfo instead of the compat siginfo Yury Norov 2015-11-17 21:16 ` Yury Norov 2015-11-17 21:16 ` [PATCH v6 18/19] arm64:ilp32: change COMPAT_ELF_PLATFORM to report a a subplatform for ILP32 Yury Norov 2015-11-17 21:16 ` Yury Norov 2015-11-18 8:11 ` Zhangjian (Bamvor) 2015-11-18 8:11 ` Zhangjian (Bamvor) 2015-11-18 11:21 ` pinskia 2015-11-18 11:21 ` pinskia at gmail.com 2015-11-18 20:25 ` Yury Norov 2015-11-18 20:25 ` Yury Norov 2015-11-18 21:47 ` Dr. Philipp Tomsich 2015-11-18 21:47 ` Dr. Philipp Tomsich 2015-11-17 21:16 ` [PATCH v6 19/19] arm64:ilp32: add ARM64_ILP32 to Kconfig Yury Norov 2015-11-17 21:16 ` Yury Norov 2015-11-18 8:00 ` [RFC2 PATCH v6 00/19] ILP32 for ARM64 Zhangjian (Bamvor) 2015-11-18 8:00 ` Zhangjian (Bamvor) 2015-11-23 16:49 ` Andreas Schwab 2015-11-23 16:49 ` Andreas Schwab 2015-12-03 17:59 ` Catalin Marinas 2015-12-03 17:59 ` Catalin Marinas 2015-12-04 15:35 ` Yury Norov 2015-12-04 15:35 ` Yury Norov 2015-12-04 17:18 ` Catalin Marinas 2015-12-04 17:18 ` Catalin Marinas
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