wireguard-linux/arch/xtensa/include/asm/uaccess.h, branch jd/unified-crypt-queue

xtensa: use "m" constraint instead of "a" in uaccess.h assembly

2019-11-26T19:33:38Z

Use "m" constraint instead of "r" for the address, as "m" allows compiler to access adjacent locations using base + offset, while "r" requires updating the base register every time. Use %[mem] * 0 + v to replace offset part of %[mem] expansion with v. It is impossible to change address alignment through the offset part on xtensa, so just ignore offset in alignment checks. Signed-off-by: Max Filippov

xtensa: fix type conversion in __get_user_[no]check

2019-10-14T21:14:21Z

__get_user_[no]check uses temporary buffer of type long to store result of __get_user_size and do sign extension on it when necessary. This doesn't work correctly for 64-bit data. Fix it by moving temporary buffer/sign extension logic to __get_user_asm. Don't do assignment of __get_user_bad result to (x) as it may not always be integer-compatible now and issue warning even when it's going to be optimized. Instead do (x) = 0; and call __get_user_bad separately. Zero initialize __x in __get_user_asm and use '+' constraint for its assembly argument, so that its value is preserved in error cases. This may add at most 1 cycle to the fast path, but saves an instruction and two padding bytes in the fixup section for each use of this macro and works for both misaligned store and store exception. Signed-off-by: Max Filippov

xtensa: clean up assembly arguments in uaccess macros

2019-10-14T19:58:06Z

Numeric assembly arguments are hard to understand and assembly code that uses them is hard to modify. Use named arguments in __check_align_*, __get_user_asm and __put_user_asm. Modify macro parameter names so that they don't affect argument names. Use '+' constraint for the [err] argument instead of having it as both input and output. Signed-off-by: Max Filippov

xtensa: fix {get,put}_user() for 64bit values

2019-10-14T18:39:50Z

First of all, on short copies __copy_{to,from}_user() return the amount of bytes left uncopied, *not* -EFAULT. get_user() and put_user() are expected to return -EFAULT on failure. Another problem is get_user(v32, (__u64 __user *)p); that should fetch 64bit value and the assign it to v32, truncating it in process. Current code, OTOH, reads 8 bytes of data and stores them at the address of v32, stomping on the 4 bytes that follow v32 itself. Signed-off-by: Al Viro Signed-off-by: Max Filippov

get rid of legacy 'get_ds()' function

2019-03-04T18:50:14Z

Every in-kernel use of this function defined it to KERNEL_DS (either as an actual define, or as an inline function). It's an entirely historical artifact, and long long long ago used to actually read the segment selector valueof '%ds' on x86. Which in the kernel is always KERNEL_DS. Inspired by a patch from Jann Horn that just did this for a very small subset of users (the ones in fs/), along with Al who suggested a script. I then just took it to the logical extreme and removed all the remaining gunk. Roughly scripted with git grep -l '(get_ds())' -- :^tools/ | xargs sed -i 's/(get_ds())/(KERNEL_DS)/' git grep -lw 'get_ds' -- :^tools/ | xargs sed -i '/^#define get_ds()/d' plus manual fixups to remove a few unusual usage patterns, the couple of inline function cases and to fix up a comment that had become stale. The 'get_ds()' function remains in an x86 kvm selftest, since in user space it actually does something relevant. Inspired-by: Jann Horn Inspired-by: Al Viro Signed-off-by: Linus Torvalds

Remove 'type' argument from access_ok() function

2019-01-04T02:57:57Z

Nobody has actually used the type (VERIFY_READ vs VERIFY_WRITE) argument of the user address range verification function since we got rid of the old racy i386-only code to walk page tables by hand. It existed because the original 80386 would not honor the write protect bit when in kernel mode, so you had to do COW by hand before doing any user access. But we haven't supported that in a long time, and these days the 'type' argument is a purely historical artifact. A discussion about extending 'user_access_begin()' to do the range checking resulted this patch, because there is no way we're going to move the old VERIFY_xyz interface to that model. And it's best done at the end of the merge window when I've done most of my merges, so let's just get this done once and for all. This patch was mostly done with a sed-script, with manual fix-ups for the cases that weren't of the trivial 'access_ok(VERIFY_xyz' form. There were a couple of notable cases: - csky still had the old "verify_area()" name as an alias. - the iter_iov code had magical hardcoded knowledge of the actual values of VERIFY_{READ,WRITE} (not that they mattered, since nothing really used it) - microblaze used the type argument for a debug printout but other than those oddities this should be a total no-op patch. I tried to fix up all architectures, did fairly extensive grepping for access_ok() uses, and the changes are trivial, but I may have missed something. Any missed conversion should be trivially fixable, though. Signed-off-by: Linus Torvalds

xtensa: don't use l32r opcode directly

2018-12-05T20:53:07Z

xtensa assembler is capable of representing register loads with either movi + addmi, l32r or const16, depending on the core configuration. Don't use '.literal' and 'l32r' directly in the code, use 'movi' and let the assembler relax them. Signed-off-by: Max Filippov

xtensa: use generic strncpy_from_user with KASAN

2017-12-17T23:34:57Z

This enables KASAN check of the destination buffer. Signed-off-by: Max Filippov

xtensa: use memset in xtensa_clear_user

2017-12-17T06:37:13Z

memset on xtensa is capable of accessing user memory, but KASAN checks if memset function is actually used for that and reports it as an error: ================================================================== BUG: KASAN: user-memory-access in padzero+0x4d/0x58 Write of size 519 at addr 0049ddf9 by task init/1 Call Trace: [] kasan_report+0x160/0x238 [] check_memory_region+0xf8/0x100 [] memset+0x20/0x34 [] padzero+0x4d/0x58 ================================================================== Use __memset in __xtensa_clear_user to avoid that. Signed-off-by: Max Filippov

get rid of unused __strncpy_from_user() instances

2017-05-16T03:40:28Z

Signed-off-by: Al Viro