From: Vincent Chen <deanbo422@gmail.com>
To: viro@ftp.linux.org.uk
Cc: greentime@andestech.com, Green Hu <green.hu@gmail.com>,
linux-kernel@vger.kernel.org, Arnd Bergmann <arnd@arndb.de>,
linux-arch@vger.kernel.org, tglx@linutronix.de,
jason@lakedaemon.net, marc.zyngier@arm.com, robh+dt@kernel.org,
netdev@vger.kernel.org, vincentc@andestech.com
Subject: Fwd: FW: [PATCH 18/31] nds32: Library functions
Date: Tue, 14 Nov 2017 12:47:04 +0800 [thread overview]
Message-ID: <CAJsyPhx+tRHWrvJg4Dr4QEEHtOy8jXAU2aP2=hHhmTmG3FsO9A@mail.gmail.com> (raw)
In-Reply-To: <E26F4CF8B7DDDB4383A6C2D78D5C3CD56B497559@ATCPCS16.andestech.com>
>>On Wed, Nov 08, 2017 at 01:55:06PM +0800, Greentime Hu wrote:
>
>> +#define __range_ok(addr, size) (size <= get_fs() && addr <= (get_fs()
>> +-size))
>> +
>> +#define access_ok(type, addr, size) \
>> + __range_ok((unsigned long)addr, (unsigned long)size)
>
>> +#define __get_user_x(__r2,__p,__e,__s,__i...) \
>> + __asm__ __volatile__ ( \
>> + __asmeq("%0", "$r0") __asmeq("%1", "$r2") \
>> + "bal __get_user_" #__s \
>
>... which does not check access_ok() or do any visible equivalents; OK...
>
>> +#define get_user(x,p) \
>> + ({ \
>> + const register typeof(*(p)) __user *__p asm("$r0") = (p);\
>> + register unsigned long __r2 asm("$r2"); \
>> + register int __e asm("$r0"); \
>> + switch (sizeof(*(__p))) { \
>> + case 1: \
>> + __get_user_x(__r2, __p, __e, 1, "$lp"); \
>
>... and neither does this, which is almost certainly *not* OK.
>
>> +#define put_user(x,p) \
>
>Same here, AFAICS.
Thanks.
I will add access_ok() in get_user/put_user
>> +extern unsigned long __arch_copy_from_user(void *to, const void __user * from,
>> + unsigned long n);
>
>> +static inline unsigned long raw_copy_from_user(void *to,
>> + const void __user * from,
>> + unsigned long n)
>> +{
>> + return __arch_copy_from_user(to, from, n); }
>
>Er... Why not call your __arch_... raw_... and be done with that?
Thanks.
I will modify it in next patch version
>> +#define INLINE_COPY_FROM_USER
>> +#define INLINE_COPY_TO_USER
>
>Are those actually worth bothering? IOW, have you compared behaviour with and without them?
We compared the assembly code of copy_from/to_user's caller function,
and we think the performance is better by making copy_from/to_user as
inline
>> +ENTRY(__arch_copy_to_user)
>> + push $r0
>> + push $r2
>> + beqz $r2, ctu_exit
>> + srli $p0, $r2, #2 ! $p0 = number of word to clear
>> + andi $r2, $r2, #3 ! Bytes less than a word to copy
>> + beqz $p0, byte_ctu ! Only less than a word to copy
>> +word_ctu:
>> + lmw.bim $p1, [$r1], $p1 ! Load the next word
>> +USER( smw.bim,$p1, [$r0], $p1) ! Store the next word
>
>Umm... It's that happy with unaligned loads and stores? Your memcpy seems to be trying to avoid those...
Thanks.
This should be aligned loads and stores, too.
I will modify it in next version patch.
>> +9001:
>> + pop $p1 ! Original $r2, n
>> + pop $p0 ! Original $r0, void *to
>> + sub $r1, $r0, $p0 ! Bytes copied
>> + sub $r2, $p1, $r1 ! Bytes left to copy
>> + push $lp
>> + move $r0, $p0
>> + bal memzero ! Clean up the memory
>
>Just what memory are you zeroing here? The one you had been unable to store into in the first place?
>
>> +ENTRY(__arch_copy_from_user)
>
>> +9001:
>> + pop $p1 ! Original $r2, n
>> + pop $p0 ! Original $r0, void *to
>> + sub $r1, $r1, $p0 ! Bytes copied
>> + sub $r2, $p1, $r1 ! Bytes left to copy
>> + push $lp
>> + bal memzero ! Clean up the memory
>
>Ditto, only this one is even worse - instead of just oopsing on you, it will quietly destroy data past the area you've copied into. raw_copy_..._user() MUST NOT ZERO ANYTHING. Ever.
Thanks
So, I should keep the area that we've copied into instead of zeroing
the area even if unpredicted exception is happened. Right?
Best regards
Vincent
next prev parent reply other threads:[~2017-11-14 4:47 UTC|newest]
Thread overview: 112+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-11-08 5:54 [PATCH 00/31] Andes(nds32) Linux Kernel Port Greentime Hu
2017-11-08 5:54 ` [PATCH 01/31] nds32: Assembly macros and definitions Greentime Hu
2017-11-08 5:54 ` [PATCH 02/31] nds32: Kernel booting and initialization Greentime Hu
2017-11-08 13:38 ` Rob Herring
2017-11-09 9:49 ` Greentime Hu
2017-11-08 5:54 ` [PATCH 03/31] nds32: Support early_printk Greentime Hu
2017-11-08 9:47 ` Tobias Klauser
2017-11-09 7:19 ` Greentime Hu
2017-11-08 5:54 ` [PATCH 04/31] nds32: Exception handling Greentime Hu
2017-11-08 8:23 ` Arnd Bergmann
[not found] ` <E26F4CF8B7DDDB4383A6C2D78D5C3CD56B4974CE@ATCPCS16.andestech.com>
2017-11-13 10:54 ` Fwd: FW: " Vincent Chen
2017-11-08 5:54 ` [PATCH 05/31] nds32: MMU definitions Greentime Hu
2017-11-08 8:36 ` Arnd Bergmann
2017-11-08 8:46 ` Greentime Hu
2017-11-08 5:54 ` [PATCH 06/31] nds32: MMU initialization Greentime Hu
2017-11-08 5:54 ` [PATCH 07/31] nds32: MMU fault handling and page table management Greentime Hu
2017-11-08 5:54 ` [PATCH 08/31] nds32: Cache and TLB routines Greentime Hu
2017-11-08 8:45 ` Arnd Bergmann
2017-11-08 9:01 ` Greentime Hu
2017-11-08 5:54 ` [PATCH 09/31] nds32: Process management Greentime Hu
2017-11-08 5:54 ` [PATCH 10/31] nds32: IRQ handling Greentime Hu
2017-11-08 8:49 ` Arnd Bergmann
2017-11-08 9:06 ` Greentime Hu
2017-11-08 5:54 ` [PATCH 11/31] nds32: Atomic operations Greentime Hu
2017-11-08 8:54 ` Arnd Bergmann
2017-11-08 9:32 ` vincentc
2017-11-20 14:29 ` Will Deacon
2017-11-22 3:02 ` Vincent Chen
2017-11-08 5:55 ` [PATCH 12/31] nds32: Device specific operations Greentime Hu
2017-11-08 9:04 ` Arnd Bergmann
2017-11-09 7:04 ` Greentime Hu
2017-11-10 16:07 ` Greentime Hu
2017-11-10 16:14 ` Arnd Bergmann
2017-11-22 10:02 ` Greentime Hu
2017-11-08 5:55 ` [PATCH 13/31] nds32: DMA mapping API Greentime Hu
2017-11-08 9:09 ` Arnd Bergmann
2017-11-09 7:12 ` Greentime Hu
2017-11-09 10:14 ` Arnd Bergmann
2017-11-10 8:13 ` Greentime Hu
2017-11-08 5:55 ` [PATCH 14/31] nds32: ELF definitions Greentime Hu
2017-11-08 5:55 ` [PATCH 15/31] nds32: System calls handling Greentime Hu
2017-11-08 9:30 ` Arnd Bergmann
[not found] ` <E26F4CF8B7DDDB4383A6C2D78D5C3CD56B497241@ATCPCS16.andestech.com>
2017-11-13 2:51 ` Fwd: FW: " Vincent Chen
2017-11-13 11:42 ` Arnd Bergmann
2017-11-22 3:13 ` Vincent Chen
2017-11-08 5:55 ` [PATCH 16/31] nds32: VDSO support Greentime Hu
2017-11-08 9:37 ` Arnd Bergmann
2017-11-08 20:00 ` Deepa Dinamani
2017-11-08 20:06 ` Arnd Bergmann
2017-11-08 20:14 ` Deepa Dinamani
2017-11-08 5:55 ` [PATCH 17/31] nds32: Signal handling support Greentime Hu
2017-11-09 1:26 ` Al Viro
[not found] ` <E26F4CF8B7DDDB4383A6C2D78D5C3CD56B497460@ATCPCS16.andestech.com>
2017-11-13 2:34 ` Fwd: FW: " Vincent Chen
2017-11-08 5:55 ` [PATCH 18/31] nds32: Library functions Greentime Hu
2017-11-08 9:45 ` Arnd Bergmann
2017-11-09 0:40 ` Al Viro
[not found] ` <E26F4CF8B7DDDB4383A6C2D78D5C3CD56B497559@ATCPCS16.andestech.com>
2017-11-14 4:47 ` Vincent Chen [this message]
2017-11-18 2:44 ` Fwd: FW: " Al Viro
2017-11-08 5:55 ` [PATCH 19/31] nds32: Debugging support Greentime Hu
2017-11-08 5:55 ` [PATCH 20/31] nds32: L2 cache support Greentime Hu
2017-11-08 9:48 ` Arnd Bergmann
2017-11-09 7:24 ` Greentime Hu
2017-11-08 5:55 ` [PATCH 21/31] nds32: Loadable modules Greentime Hu
2017-11-08 5:55 ` [PATCH 22/31] nds32: Generic timers support Greentime Hu
2017-11-08 5:55 ` [PATCH 23/31] nds32: Device tree support Greentime Hu
2017-11-08 9:53 ` Arnd Bergmann
2017-11-09 7:48 ` Greentime Hu
2017-11-08 5:55 ` [PATCH 24/31] nds32: Miscellaneous header files Greentime Hu
2017-11-08 9:57 ` Arnd Bergmann
2017-11-08 5:55 ` [PATCH 25/31] nds32: defconfig Greentime Hu
2017-11-08 10:03 ` Arnd Bergmann
2017-11-09 8:00 ` Greentime Hu
2017-11-09 10:20 ` Arnd Bergmann
2017-11-10 8:16 ` Greentime Hu
2017-11-08 5:55 ` [PATCH 26/31] nds32: Build infrastructure Greentime Hu
2017-11-08 10:16 ` Arnd Bergmann
2017-11-09 9:02 ` Greentime Hu
2017-11-09 10:33 ` Arnd Bergmann
2017-11-10 8:26 ` Greentime Hu
2017-11-17 12:39 ` Greentime Hu
2017-11-17 12:50 ` Arnd Bergmann
2017-11-17 13:50 ` Greentime Hu
2017-11-13 10:45 ` Geert Uytterhoeven
2017-11-16 10:03 ` Greentime Hu
2017-11-16 10:25 ` Arnd Bergmann
2017-11-17 13:53 ` Greentime Hu
2017-11-08 5:55 ` [PATCH 27/31] dt-bindings: interrupt-controller: Andestech Internal Vector Interrupt Controller Greentime Hu
2017-11-08 13:25 ` Rob Herring
2017-11-09 9:43 ` Greentime Hu
2017-11-08 5:55 ` [PATCH 28/31] irqchip: Andestech Internal Vector Interrupt Controller driver Greentime Hu
2017-11-08 14:24 ` Marc Zyngier
2017-11-09 10:10 ` Greentime Hu
2017-11-08 5:55 ` [PATCH 29/31] MAINTAINERS: Add nds32 Greentime Hu
2017-11-08 13:31 ` Rob Herring
2017-11-09 9:46 ` Greentime Hu
2017-11-09 10:36 ` Arnd Bergmann
2017-11-14 15:39 ` Joe Perches
2017-11-16 12:22 ` Greentime Hu
2017-11-08 5:55 ` [PATCH 30/31] dt-bindings: nds32 CPU Bindings Greentime Hu
2017-11-08 13:18 ` Rob Herring
2017-11-09 9:39 ` Greentime Hu
2017-11-09 13:57 ` Rob Herring
2017-11-10 6:22 ` Greentime Hu
2017-11-10 8:25 ` Arnd Bergmann
2017-11-10 8:43 ` Greentime Hu
2017-11-08 5:55 ` [PATCH 31/31] net: faraday add nds32 support Greentime Hu
2017-11-08 8:32 ` [PATCH 00/31] Andes(nds32) Linux Kernel Port David Howells
2017-11-08 8:41 ` Greentime Hu
2017-11-08 10:18 ` Arnd Bergmann
2017-11-09 9:26 ` Greentime Hu
2017-11-08 10:26 ` Arnd Bergmann
2017-11-09 9:33 ` Greentime Hu
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