On Thu, 2 Apr 2020 at 13:15, Catalin Marinas <catalin.marinas@xxxxxxx> wrote: > > On Sun, Mar 29, 2020 at 04:12:58PM +0200, Ard Biesheuvel wrote: > > When CONFIG_DEBUG_ALIGN_RODATA is enabled, kernel segments mapped with > > different permissions (r-x for .text, r-- for .rodata, rw- for .data, > > etc) are rounded up to 2 MiB so they can be mapped more efficiently. > > In particular, it permits the segments to be mapped using level 2 > > block entries when using 4k pages, which is expected to result in less > > TLB pressure. > > > > However, the mappings for the bulk of the kernel will use level 2 > > entries anyway, and the misaligned fringes are organized such that they > > can take advantage of the contiguous bit, and use far fewer level 3 > > entries than would be needed otherwise. > > > > This makes the value of this feature dubious at best, and since it is not > > enabled in defconfig or in the distro configs, it does not appear to be > > in wide use either. So let's just remove it. > > > > Signed-off-by: Ard Biesheuvel <ardb@xxxxxxxxxx> > > Happy to take this patch via the arm64 tree for 5.7 (no new > functionality), unless you want it to go with your other relocation > login in the EFI stub patches. > If you don't mind taking it for v5.7, please go ahead.
