user/sven/linux.git/include, branch v5.15.44

random: move randomize_page() into mm where it belongs

2022-05-30T07:29:17Z

commit 5ad7dd882e45d7fe432c32e896e2aaa0b21746ea upstream. randomize_page is an mm function. It is documented like one. It contains the history of one. It has the naming convention of one. It looks just like another very similar function in mm, randomize_stack_top(). And it has always been maintained and updated by mm people. There is no need for it to be in random.c. In the "which shape does not look like the other ones" test, pointing to randomize_page() is correct. So move randomize_page() into mm/util.c, right next to the similar randomize_stack_top() function. This commit contains no actual code changes. Cc: Andrew Morton Signed-off-by: Jason A. Donenfeld Signed-off-by: Greg Kroah-Hartman

random: make consistent use of buf and len

2022-05-30T07:29:17Z

commit a19402634c435a4eae226df53c141cdbb9922e7b upstream. The current code was a mix of "nbytes", "count", "size", "buffer", "in", and so forth. Instead, let's clean this up by naming input parameters "buf" (or "ubuf") and "len", so that you always understand that you're reading this variety of function argument. Signed-off-by: Jason A. Donenfeld Signed-off-by: Greg Kroah-Hartman

random: use proper return types on get_random_{int,long}_wait()

2022-05-30T07:29:17Z

commit 7c3a8a1db5e03d02cc0abb3357a84b8b326dfac3 upstream. Before these were returning signed values, but the API is intended to be used with unsigned values. Signed-off-by: Jason A. Donenfeld Signed-off-by: Greg Kroah-Hartman

random: remove extern from functions in header

2022-05-30T07:29:17Z

commit 7782cfeca7d420e8bb707613d4cfb0f7ff29bb3a upstream. Accoriding to the kernel style guide, having `extern` on functions in headers is old school and deprecated, and doesn't add anything. So remove them from random.h, and tidy up the file a little bit too. Signed-off-by: Jason A. Donenfeld Signed-off-by: Greg Kroah-Hartman

random: handle latent entropy and command line from random_init()

2022-05-30T07:29:16Z

commit 2f14062bb14b0fcfcc21e6dc7d5b5c0d25966164 upstream. Currently, start_kernel() adds latent entropy and the command line to the entropy bool *after* the RNG has been initialized, deferring when it's actually used by things like stack canaries until the next time the pool is seeded. This surely is not intended. Rather than splitting up which entropy gets added where and when between start_kernel() and random_init(), just do everything in random_init(), which should eliminate these kinds of bugs in the future. While we're at it, rename the awkwardly titled "rand_initialize()" to the more standard "random_init()" nomenclature. Reviewed-by: Dominik Brodowski Signed-off-by: Jason A. Donenfeld Signed-off-by: Greg Kroah-Hartman

siphash: use one source of truth for siphash permutations

2022-05-30T07:29:15Z

commit e73aaae2fa9024832e1f42e30c787c7baf61d014 upstream. The SipHash family of permutations is currently used in three places: - siphash.c itself, used in the ordinary way it was intended. - random32.c, in a construction from an anonymous contributor. - random.c, as part of its fast_mix function. Each one of these places reinvents the wheel with the same C code, same rotation constants, and same symmetry-breaking constants. This commit tidies things up a bit by placing macros for the permutations and constants into siphash.h, where each of the three .c users can access them. It also leaves a note dissuading more users of them from emerging. Signed-off-by: Jason A. Donenfeld Signed-off-by: Greg Kroah-Hartman

timekeeping: Add raw clock fallback for random_get_entropy()

2022-05-30T07:29:13Z

commit 1366992e16bddd5e2d9a561687f367f9f802e2e4 upstream. The addition of random_get_entropy_fallback() provides access to whichever time source has the highest frequency, which is useful for gathering entropy on platforms without available cycle counters. It's not necessarily as good as being able to quickly access a cycle counter that the CPU has, but it's still something, even when it falls back to being jiffies-based. In the event that a given arch does not define get_cycles(), falling back to the get_cycles() default implementation that returns 0 is really not the best we can do. Instead, at least calling random_get_entropy_fallback() would be preferable, because that always needs to return _something_, even falling back to jiffies eventually. It's not as though random_get_entropy_fallback() is super high precision or guaranteed to be entropic, but basically anything that's not zero all the time is better than returning zero all the time. Finally, since random_get_entropy_fallback() is used during extremely early boot when randomizing freelists in mm_init(), it can be called before timekeeping has been initialized. In that case there really is nothing we can do; jiffies hasn't even started ticking yet. So just give up and return 0. Suggested-by: Thomas Gleixner Signed-off-by: Jason A. Donenfeld Reviewed-by: Thomas Gleixner Cc: Arnd Bergmann Cc: Theodore Ts'o Signed-off-by: Jason A. Donenfeld Signed-off-by: Greg Kroah-Hartman

random: make random_get_entropy() return an unsigned long

2022-05-30T07:29:12Z

commit b0c3e796f24b588b862b61ce235d3c9417dc8983 upstream. Some implementations were returning type `unsigned long`, while others that fell back to get_cycles() were implicitly returning a `cycles_t` or an untyped constant int literal. That makes for weird and confusing code, and basically all code in the kernel already handled it like it was an `unsigned long`. I recently tried to handle it as the largest type it could be, a `cycles_t`, but doing so doesn't really help with much. Instead let's just make random_get_entropy() return an unsigned long all the time. This also matches the commonly used `arch_get_random_long()` function, so now RDRAND and RDTSC return the same sized integer, which means one can fallback to the other more gracefully. Cc: Dominik Brodowski Cc: Theodore Ts'o Acked-by: Thomas Gleixner Signed-off-by: Jason A. Donenfeld Signed-off-by: Greg Kroah-Hartman

random: replace custom notifier chain with standard one

2022-05-30T07:29:10Z

commit 5acd35487dc911541672b3ffc322851769c32a56 upstream. We previously rolled our own randomness readiness notifier, which only has two users in the whole kernel. Replace this with a more standard atomic notifier block that serves the same purpose with less code. Also unexport the symbols, because no modules use it, only unconditional builtins. The only drawback is that it's possible for a notification handler returning the "stop" code to prevent further processing, but given that there are only two users, and that we're unexporting this anyway, that doesn't seem like a significant drawback for the simplification we receive here. Cc: Greg Kroah-Hartman Cc: Theodore Ts'o Reviewed-by: Dominik Brodowski [Jason: for stable, also backported to crypto/drbg.c, not unexporting.] Signed-off-by: Jason A. Donenfeld Signed-off-by: Greg Kroah-Hartman

random: clear fast pool, crng, and batches in cpuhp bring up

2022-05-30T07:29:09Z

commit 3191dd5a1179ef0fad5a050a1702ae98b6251e8f upstream. For the irq randomness fast pool, rather than having to use expensive atomics, which were visibly the most expensive thing in the entire irq handler, simply take care of the extreme edge case of resetting count to zero in the cpuhp online handler, just after workqueues have been reenabled. This simplifies the code a bit and lets us use vanilla variables rather than atomics, and performance should be improved. As well, very early on when the CPU comes up, while interrupts are still disabled, we clear out the per-cpu crng and its batches, so that it always starts with fresh randomness. Cc: Thomas Gleixner Cc: Peter Zijlstra Cc: Theodore Ts'o Cc: Sultan Alsawaf Cc: Dominik Brodowski Acked-by: Sebastian Andrzej Siewior Signed-off-by: Jason A. Donenfeld Signed-off-by: Greg Kroah-Hartman