From: Al Viro <viro@zeniv.linux.org.uk>
To: Christoph Hellwig <hch@lst.de>
Cc: Paul Walmsley <paul.walmsley@sifive.com>,
Palmer Dabbelt <palmer@dabbelt.com>,
Arnd Bergmann <arnd@arndb.de>,
linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org,
linux-arch@vger.kernel.org
Subject: Re: [PATCH 3/8] asm-generic: fix unaligned access hamdling in raw_copy_{from,to}_user
Date: Sat, 5 Sep 2020 15:41:36 +0100 [thread overview]
Message-ID: <20200905144136.GA2604093@ZenIV.linux.org.uk> (raw)
In-Reply-To: <20200904223518.GR1236603@ZenIV.linux.org.uk>
On Fri, Sep 04, 2020 at 11:35:18PM +0100, Al Viro wrote:
> Now, if you look at raw_copy_from_user() you'll see an interesting
> picture: some architectures special-case the handling of small constant sizes.
> Namely,
> arc (any size; inlining in there is obscene, constant size or not),
> c6x (1,4,8),
> m68k/MMU (1,2,3,4,5,6,7,8,9,10,12)
> ppc (1,2,4,8),
> h8300 (1,2,4),
> riscv (with your series)(1,2,4, 8 if 64bit).
FWIW, on the raw_copy_to_user() side the same set of constant sizes is
recongized by the same architectures and we have
* __put_user/put_user in asm-generic/uaccess.h make use of that
* arc, c6x, ppc and riscv using it to store sigset_t on sigframe
* 3 odd callers:
* arc stash_usr_regs(), inlined and unrolled large copy_to_user()
* ppc kvm_htab_read(), 64bit store.
* i915_gem_execbuffer_ioctl():
if (__copy_to_user(&user_exec_list[i].offset,
&exec2_list[i].offset,
sizeof(user_exec_list[i].offset)))
in a loop. 'offset' here is __u64.
That's it. IOW, asm-generic put_user() is the only real cause to have those
magic sizes recognized on raw_copy_to_user() side.
WARNING: multiple messages have this Message-ID (diff)
From: Al Viro <viro@zeniv.linux.org.uk>
To: Christoph Hellwig <hch@lst.de>
Cc: linux-arch@vger.kernel.org, Arnd Bergmann <arnd@arndb.de>,
linux-kernel@vger.kernel.org, Palmer Dabbelt <palmer@dabbelt.com>,
Paul Walmsley <paul.walmsley@sifive.com>,
linux-riscv@lists.infradead.org
Subject: Re: [PATCH 3/8] asm-generic: fix unaligned access hamdling in raw_copy_{from,to}_user
Date: Sat, 5 Sep 2020 15:41:36 +0100 [thread overview]
Message-ID: <20200905144136.GA2604093@ZenIV.linux.org.uk> (raw)
In-Reply-To: <20200904223518.GR1236603@ZenIV.linux.org.uk>
On Fri, Sep 04, 2020 at 11:35:18PM +0100, Al Viro wrote:
> Now, if you look at raw_copy_from_user() you'll see an interesting
> picture: some architectures special-case the handling of small constant sizes.
> Namely,
> arc (any size; inlining in there is obscene, constant size or not),
> c6x (1,4,8),
> m68k/MMU (1,2,3,4,5,6,7,8,9,10,12)
> ppc (1,2,4,8),
> h8300 (1,2,4),
> riscv (with your series)(1,2,4, 8 if 64bit).
FWIW, on the raw_copy_to_user() side the same set of constant sizes is
recongized by the same architectures and we have
* __put_user/put_user in asm-generic/uaccess.h make use of that
* arc, c6x, ppc and riscv using it to store sigset_t on sigframe
* 3 odd callers:
* arc stash_usr_regs(), inlined and unrolled large copy_to_user()
* ppc kvm_htab_read(), 64bit store.
* i915_gem_execbuffer_ioctl():
if (__copy_to_user(&user_exec_list[i].offset,
&exec2_list[i].offset,
sizeof(user_exec_list[i].offset)))
in a loop. 'offset' here is __u64.
That's it. IOW, asm-generic put_user() is the only real cause to have those
magic sizes recognized on raw_copy_to_user() side.
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next prev parent reply other threads:[~2020-09-05 14:41 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-04 16:52 remove set_fs for riscv Christoph Hellwig
2020-09-04 16:52 ` Christoph Hellwig
2020-09-04 16:52 ` [PATCH 1/8] maccess: add a generic __{get,put}_kernel_nofault for nommu Christoph Hellwig
2020-09-04 16:52 ` [PATCH 1/8] maccess: add a generic __{get, put}_kernel_nofault " Christoph Hellwig
2020-09-04 16:52 ` [PATCH 2/8] uaccess: provide a generic TASK_SIZE_MAX definition Christoph Hellwig
2020-09-04 16:52 ` Christoph Hellwig
2020-09-04 16:52 ` [PATCH 3/8] asm-generic: fix unaligned access hamdling in raw_copy_{from,to}_user Christoph Hellwig
2020-09-04 16:52 ` [PATCH 3/8] asm-generic: fix unaligned access hamdling in raw_copy_{from, to}_user Christoph Hellwig
2020-09-04 18:04 ` [PATCH 3/8] asm-generic: fix unaligned access hamdling in raw_copy_{from,to}_user Arnd Bergmann
2020-09-04 18:04 ` [PATCH 3/8] asm-generic: fix unaligned access hamdling in raw_copy_{from, to}_user Arnd Bergmann
2020-09-05 7:14 ` [PATCH 3/8] asm-generic: fix unaligned access hamdling in raw_copy_{from,to}_user Christoph Hellwig
2020-09-05 7:14 ` Christoph Hellwig
2020-09-04 18:06 ` Al Viro
2020-09-04 18:06 ` Al Viro
2020-09-04 22:35 ` Al Viro
2020-09-04 22:35 ` Al Viro
2020-09-05 14:41 ` Al Viro [this message]
2020-09-05 14:41 ` Al Viro
2020-09-07 8:07 ` Arnd Bergmann
2020-09-07 8:07 ` [PATCH 3/8] asm-generic: fix unaligned access hamdling in raw_copy_{from, to}_user Arnd Bergmann
2020-09-07 19:00 ` Sean Anderson
2020-09-07 19:00 ` Sean Anderson
2020-09-04 16:52 ` [PATCH 4/8] asm-generic: prepare uaccess.h for a set_fs-less world Christoph Hellwig
2020-09-04 16:52 ` Christoph Hellwig
2020-09-04 16:52 ` [PATCH 5/8] riscv: use memcpy based uaccess for nommu again Christoph Hellwig
2020-09-04 16:52 ` Christoph Hellwig
2020-09-04 16:52 ` [PATCH 6/8] riscv: refactor __get_user and __put_user Christoph Hellwig
2020-09-04 16:52 ` Christoph Hellwig
2020-09-04 16:52 ` [PATCH 7/8] riscv: implement __get_kernel_nofault and __put_user_nofault Christoph Hellwig
2020-09-04 16:52 ` Christoph Hellwig
2020-09-04 16:52 ` [PATCH 8/8] riscv: remove address space overrides using set_fs() Christoph Hellwig
2020-09-04 16:52 ` Christoph Hellwig
2020-09-04 18:15 ` remove set_fs for riscv Arnd Bergmann
2020-09-04 18:15 ` Arnd Bergmann
2020-09-05 7:17 ` Christoph Hellwig
2020-09-05 7:17 ` Christoph Hellwig
2020-09-05 12:17 ` Arnd Bergmann
2020-09-05 12:17 ` Arnd Bergmann
2020-09-06 22:14 ` Arnd Bergmann
2020-09-06 22:14 ` Arnd Bergmann
2020-09-07 6:03 ` Christoph Hellwig
2020-09-07 6:03 ` Christoph Hellwig
2020-09-07 14:58 ` Arnd Bergmann
2020-09-07 14:58 ` Arnd Bergmann
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