On Wed, Aug 28, 2024 at 02:26:08PM +0200, Jason A. Donenfeld wrote:
On Wed, Aug 28, 2024 at 2:24 PM Arnd Bergmann arnd@arndb.de wrote:
On Wed, Aug 28, 2024, at 11:18, Jason A. Donenfeld wrote:
On Tue, Aug 27, 2024 at 05:53:30PM -0500, Segher Boessenkool wrote:
On Tue, Aug 27, 2024 at 11:08:19AM -0700, Eric Biggers wrote:
Is there a compiler flag that could be used to disable the generation of calls to memset?
-fno-tree-loop-distribute-patterns . But, as always, read up on it, see what it actually does (and how it avoids your problem, and mostly: learn what the actual problem *was*!)
This might help with various loops, but it doesn't help with the matter that this patch fixes, which is struct initialization. I just tried it with the arm64 patch to no avail.
Maybe -ffreestanding can help here? That should cause the vdso to be built with the assumption that there is no libc, so it would neither add nor remove standard library calls. Not sure if that causes other problems, e.g. if the calling conventions are different.
| You need -ffreestanding but that is documented to emit memset and memcpy still.
Yeah.
'-nostdlib' Do not use the standard system startup files or libraries when linking.
This won't help a bit, the compiler will still optimise your initialisation loop to a memset() call, it just won't link to libgcc.a and crt*.o and its ilk (which is not where mem* are implemented in the first place!)
Segher