kernel/linux.git/arch/csky/lib, branch v6.6.132

csky: delay: Add function alignment

2022-12-30T04:47:52+00:00

Specify 8 bytes alignment for the function __delay or we get bad delay like udelay(10) will be 25us in fact. Signed-off-by: Jialu Xu Signed-off-by: Guo Ren

csky: Add C based string functions

2022-04-18T13:23:55+00:00

Try to access RAM with the largest bit width possible, but without doing unaligned accesses. A further improvement could be to use multiple read and writes as the assembly version was trying to do. Tested on a BeagleV Starlight with a SiFive U74 core, where the improvement is noticeable. Signed-off-by: Matteo Croce Co-developed-by: Guo Ren Signed-off-by: Guo Ren

csky: use generic strncpy/strnlen from_user

2021-07-23T12:40:01+00:00

Remove the csky implemenation of strncpy/strnlen and instead use the generic versions. The csky version is fairly slow because it always does byte accesses even for aligned data, and it lacks a checks for user_addr_max(). Reviewed-by: Christoph Hellwig Signed-off-by: Arnd Bergmann

asm-generic/uaccess.h: remove __strncpy_from_user/__strnlen_user

2021-07-23T12:39:56+00:00

This is a preparation for changing over architectures to the generic implementation one at a time. As there are no callers of either __strncpy_from_user() or __strnlen_user(), fold these into the strncpy_from_user() and strnlen_user() functions to make each implementation independent of the others. Many of these implementations have known bugs, but the intention here is to not change behavior at all and stay compatible with those bugs for the moment. Reviewed-by: Christoph Hellwig Signed-off-by: Arnd Bergmann

Merge tag 'csky-for-linus-5.13-rc1' of git://github.com/c-sky/csky-linux

2021-05-03T19:58:31+00:00

Pull arch/csky updates from Guo Ren: "Just cleanups" * tag 'csky-for-linus-5.13-rc1' of git://github.com/c-sky/csky-linux: csky: uaccess.h: Coding convention with asm generic csky: fix syscache.c fallthrough warning csky: Fixup typos csky: Remove duplicate include in arch/csky/kernel/entry.S

csky: uaccess.h: Coding convention with asm generic

2021-04-28T15:02:23+00:00

Using asm-generic/uaccess.h to prevent duplicated code: - Add user_addr_max which mentioned in generic uaccess.h - Remove custom definitions of KERNEL/USER_DS, get/set_fs, uaccess_kerenl - Using generic extable.h instead of custom definitions in uaccess.h Change v2: - Fixup tinyconfig compile error, "__put_user_bad" - Add __get_user_asm_64 Signed-off-by: Guo Ren Link: https://lore.kernel.org/linux-csky/CAK8P3a1DvsXSEDoovLk11hzNHyJi7vqNoToU+n5aFi2viZO_Uw@mail.gmail.com/T/#mbcd58a0e3450e5598974116b607589afa16a3ab7 Cc: Arnd Bergmann

whack-a-mole: kill strlen_user() (again)

2021-03-27T23:36:31+00:00

Signed-off-by: Al Viro

csky: Add support for function error injection

2020-07-31T01:52:07+00:00

Inspired by the commit 42d038c4fb00 ("arm64: Add support for function error injection"), this patch supports function error injection for csky. This patch mainly support two functions: one is regs_set_return_value() which is used to overwrite the return value; the another function is override_function_with_return() which is to override the probed function returning and jump to its caller. Test log: cd /sys/kernel/debug/fail_function/ echo sys_clone > inject echo 100 > probability echo 1 > interval ls / [ 108.644163] FAULT_INJECTION: forcing a failure. [ 108.644163] name fail_function, interval 1, probability 100, space 0, times 1 [ 108.647799] CPU: 0 PID: 104 Comm: sh Not tainted 5.8.0-rc5+ #46 [ 108.648384] Call Trace: [ 108.649339] [<8005eed4>] walk_stackframe+0x0/0xf0 [ 108.649679] [<8005f16a>] show_stack+0x32/0x5c [ 108.649927] [<8040f9d2>] dump_stack+0x6e/0x9c [ 108.650271] [<80406f7e>] should_fail+0x15e/0x1ac [ 108.650720] [<80118ba8>] fei_kprobe_handler+0x28/0x5c [ 108.651519] [<80754110>] kprobe_breakpoint_handler+0x144/0x1cc [ 108.652289] [<8005d6da>] trap_c+0x8e/0x110 [ 108.652816] [<8005ce8c>] csky_trap+0x5c/0x70 -sh: can't fork: Invalid argument Signed-off-by: Guo Ren Cc: Arnd Bergmann

csky: Fixup raw_copy_from_user()

2020-05-14T16:16:30+00:00

If raw_copy_from_user(to, from, N) returns K, callers expect the first N - K bytes starting at to to have been replaced with the contents of corresponding area starting at from and the last K bytes of destination *left* *unmodified*. What arch/sky/lib/usercopy.c is doing is broken - it can lead to e.g. data corruption on write(2). raw_copy_to_user() is inaccurate about return value, which is a bug, but consequences are less drastic than for raw_copy_from_user(). And just what are those access_ok() doing in there? I mean, look into linux/uaccess.h; that's where we do that check (as well as zero tail on failure in the callers that need zeroing). AFAICS, all of that shouldn't be hard to fix; something like a patch below might make a useful starting point. I would suggest moving these macros into usercopy.c (they are never used anywhere else) and possibly expanding them there; if you leave them alive, please at least rename __copy_user_zeroing(). Again, it must not zero anything on failed read. Said that, I'm not sure we won't be better off simply turning usercopy.c into usercopy.S - all that is left there is a couple of functions, each consisting only of inline asm. Guo Ren reply: Yes, raw_copy_from_user is wrong, it's no need zeroing code. unsigned long _copy_from_user(void *to, const void __user *from, unsigned long n) { unsigned long res = n; might_fault(); if (likely(access_ok(from, n))) { kasan_check_write(to, n); res = raw_copy_from_user(to, from, n); } if (unlikely(res)) memset(to + (n - res), 0, res); return res; } EXPORT_SYMBOL(_copy_from_user); You are right and access_ok() should be removed. but, how about: do { ... "2: stw %3, (%1, 0) \n" \ + " subi %0, 4 \n" \ "9: stw %4, (%1, 4) \n" \ + " subi %0, 4 \n" \ "10: stw %5, (%1, 8) \n" \ + " subi %0, 4 \n" \ "11: stw %6, (%1, 12) \n" \ + " subi %0, 4 \n" \ " addi %2, 16 \n" \ " addi %1, 16 \n" \ Don't expand __ex_table AI Viro reply: Hey, I've no idea about the instruction scheduling on csky - if that doesn't slow the things down, all the better. It's just that copy_to_user() and friends are on fairly hot codepaths, and in quite a few situations they will dominate the speed of e.g. read(2). So I tried to keep the fast path unchanged. Up to the architecture maintainers, obviously. Which would be you... As for the fixups size increase (__ex_table size is unchanged)... You have each of those macros expanded exactly once. So the size is not a serious argument, IMO - useless complexity would be, if it is, in fact, useless; the size... not really, especially since those extra subi will at least offset it. Again, up to you - asm optimizations of (essentially) memcpy()-style loops are tricky and can depend upon the fairly subtle details of architecture. So even on something I know reasonably well I would resort to direct experiments if I can't pass the buck to architecture maintainers. It *is* worth optimizing - this is where read() from a file that is already in page cache spends most of the time, etc. Guo Ren reply: Thx, after fixup some typo “sub %0, 4”, apply the patch. TODO: - user copy/from codes are still need optimizing. Signed-off-by: Al Viro Signed-off-by: Guo Ren

treewide: Add SPDX license identifier - Makefile/Kconfig

2019-05-21T08:50:46+00:00

Add SPDX license identifiers to all Make/Kconfig files which: - Have no license information of any form These files fall under the project license, GPL v2 only. The resulting SPDX license identifier is: GPL-2.0-only Signed-off-by: Thomas Gleixner Signed-off-by: Greg Kroah-Hartman