Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 of the license or at your option any later version this program is distributed in the hope that it will be useful but without any warranty without even the implied warranty of merchantability or fitness for a particular purpose see the gnu general public license for more details you should have received a copy of the gnu general public license along with this program if not write to the free software foundation inc 51 franklin st fifth floor boston ma 02110 1301 usa extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 50 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Allison Randal <allison@lohutok.net> Reviewed-by: Richard Fontana <rfontana@redhat.com> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190523091649.499889647@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Commit 9e343e87d2c4 ("mtd: cfi: convert inline functions to macros")
changed map_word_andequal() into a macro, but also changed the right
hand side of the comparison from val3 to val2. Change it back to use
val3 on the right hand side.
Thankfully this did not cause a regression because all callers
currently pass the same argument for val2 and val3.
Fixes: 9e343e87d2c4 ("mtd: cfi: convert inline functions to macros")
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>
The map_word_() functions, dating back to linux-2.6.8, try to perform bitwise operations on a 'map_word' structure. This may have worked with compilers that were current then (gcc-3.4 or earlier), but end up being rather inefficient on any version I could try now (gcc-4.4 or higher). Specifically we hit a problem analyzed in gcc PR81715 where we fail to reuse the stack space for local variables. This can be seen immediately in the stack consumption for cfi_staa_erase_varsize() and other functions that (with CONFIG_KASAN) can be up to 2200 bytes. Changing the inline functions into macros brings this down to 1280 bytes. Without KASAN, the same problem exists, but the stack consumption is lower to start with, my patch shrinks it from 920 to 496 bytes on with arm-linux-gnueabi-gcc-5.4, and saves around 1KB in .text size for cfi_cmdset_0020.c, as it avoids copying map_word structures for each call to one of these helpers. With the latest gcc-8 snapshot, the problem is fixed in upstream gcc, but nobody uses that yet, so we should still work around it in mainline kernels and probably backport the workaround to stable kernels as well. We had a couple of other functions that suffered from the same gcc bug, and all of those had a simpler workaround involving dummy variables in the inline function. Unfortunately that did not work here, the macro hack was the best I could come up with. It would also be helpful to have someone to a little performance testing on the patch, to see how much it helps in terms of CPU utilitzation. Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81715 Cc: stable@vger.kernel.org Signed-off-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Richard Weinberger <richard@nod.at> Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
When map_word gets too large, we use a lot of kernel stack, and for
MTD_MAP_BANK_WIDTH_32, this means we use more than the recommended
1024 bytes in a number of functions:
drivers/mtd/chips/cfi_cmdset_0020.c: In function 'cfi_staa_write_buffers':
drivers/mtd/chips/cfi_cmdset_0020.c:651:1: warning: the frame size of 1336 bytes is larger than 1024 bytes [-Wframe-larger-than=]
drivers/mtd/chips/cfi_cmdset_0020.c: In function 'cfi_staa_erase_varsize':
drivers/mtd/chips/cfi_cmdset_0020.c:972:1: warning: the frame size of 1208 bytes is larger than 1024 bytes [-Wframe-larger-than=]
drivers/mtd/chips/cfi_cmdset_0001.c: In function 'do_write_buffer':
drivers/mtd/chips/cfi_cmdset_0001.c:1835:1: warning: the frame size of 1240 bytes is larger than 1024 bytes [-Wframe-larger-than=]
This can be avoided if all operations on the map word are done
indirectly and the stack gets reused between the calls. We can
mostly achieve this by selecting MTD_COMPLEX_MAPPINGS whenever
MTD_MAP_BANK_WIDTH_32 is set, but for the case that no other
bank width is enabled, we also need to use a non-constant
map_bankwidth() to convince the compiler to use less stack.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
[Brian: this patch mostly achieves its goal by forcing
MTD_COMPLEX_MAPPINGS (and the accompanying indirection) for 256-bit
mappings; the rest of the change is mostly a wash, though it helps
reduce stack size slightly. If we really care about supporting
256-bit mappings though, we should consider rewriting some of this
code to avoid keeping and assigning so many 256-bit objects on the
stack.]
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
As of commit 876fe76d793d03077eb61ba3afab4a383f46c554
"mtd: maps: physmap: Add reference counter to set_vpp()"
the comment in the header file is incorrect and misleading.
Fix it up.
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Paul Parsons <lost.distance@yahoo.com>
Fixes: 876fe76d793d ("mtd: maps: physmap: Add reference counter to set_vpp()")
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
The linux/mtd/map.h header file is included by a couple of platform specific files that are built even when CONFIG_MTD is disabled, and we always get warning "No CONFIG_MTD_MAP_BANK_WIDTH_xx selected. No NOR chip support can work" in that case. This adds an #ifdef around the pointless warning, as everything is really fine when we don't build the drivers anyway. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Preparation for uniform definition of ioremap, ioremap_wc, ioremap_wt, and ioremap_cache, tree-wide. Acked-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
As the only comments I got for the "mtd: cfi: reduce stack size" patch were about whitespace changes, it appears necessary to fix up the rest of the file as well, which contains the exact same mistakes. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Brian Norris <computersforpeace@gmail.com>
The cfi_staa_write_buffers function uses a large amount of kernel stack whenever CONFIG_MTD_MAP_BANK_WIDTH_32 is set, and that results in a warning on ARM allmodconfig builds: drivers/mtd/chips/cfi_cmdset_0020.c: In function 'cfi_staa_write_buffers': drivers/mtd/chips/cfi_cmdset_0020.c:651:1: warning: the frame size of 1208 bytes is larger than 1024 bytes [-Wframe-larger-than=] It turns out that this is largely a result of a suboptimal implementation of map_word_andequal(). Replacing this function with a straightforward one reduces the stack size in this function by exactly 200 bytes, shrinks the .text segment for this file from 27648 bytes to 26608 bytes, and makes the warning go away. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Hardware:
CPU: XLP832,the 64-bit OS
NOR Flash:S29GL128S 128M
Software:
Kernel:2.6.32.41
Filesystem:JFFS2
When writing files, errors appear:
Write len 182 but return retlen 180
Write of 182 bytes at 0x072c815c failed. returned -5, retlen 180
Write len 186 but return retlen 184
Write of 186 bytes at 0x072caff4 failed. returned -5, retlen 184
These errors exist only in 64-bit systems,not in 32-bit systems. After analysis, we
found that the left shift operation is wrong in map_word_load_partial. For instance:
unsigned char buf[3] ={0x9e,0x3a,0xea};
map_bankwidth(map) is 4;
for (i=0; i < 3; i++) {
int bitpos;
bitpos = (map_bankwidth(map)-1-i)*8;
orig.x[0] &= ~(0xff << bitpos);
orig.x[0] |= buf[i] << bitpos;
}
The value of orig.x[0] is expected to be 0x9e3aeaff, but in this situation(64-bit
System) we'll get the wrong value of 0xffffffff9e3aeaff due to the 64-bit sign
extension:
buf[i] is defined as "unsigned char" and the left-shift operation will convert it
to the type of "signed int", so when left-shift buf[i] by 24 bits, the final result
will get the wrong value: 0xffffffff9e3aeaff.
If the left-shift bits are less than 24, then sign extension will not occur. Whereas
the bankwidth of the nor flash we used is 4, therefore this BUG emerges.
Signed-off-by: Pang Xunlei <pang.xunlei@zte.com.cn>
Signed-off-by: Zhang Yi <zhang.yi20@zte.com.cn>
Signed-off-by: Lu Zhongjun <lu.zhongjun@zte.com.cn>
Cc: <stable@vger.kernel.org>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>