On Fri, Apr 19, 2024 at 7:24 AM Mikulas Patocka <[email protected]> wrote: > > > > On Fri, 19 Apr 2024, H.J. Lu wrote: > > > On Fri, Apr 19, 2024 at 7:08 AM Mikulas Patocka <[email protected]> wrote: > > > > > > I'd like to ask what to do with it? We could use LD_BIND_NOW=1 (or > > > -Wl,-z,now) - it mostly works, but not entirely - the key may still be > > > present on the stack even if we use LD_BIND_NOW=1. > > > > Since vector registers are saved on stack only during symbol lookup, > > shouldn't disabling lazy binding solve this issue? > > It should, but it doesn't fix this problem entirely. > > If I set "GLIBC_TUNABLES=glibc.cpu.hwcaps=-AVX512F,-AVX2" "LD_BIND_NOW=1", > I still get a failure (I don't get the failure if I don't set > GLIBC_TUNABLES and set only LD_BIND_NOW). > > So, even if we use plain SSE, the data somehow end up on the stack. >
You should write your own memory copy function and compile it with -fzero-call-used-regs if possible. -- H.J.
