Re: [PATCH 1/9] kernel: add a PF_FORCE_COMPAT flag
From: Arnd Bergmann <arnd@arndb.de>
Date: 2020-09-20 20:49:33
Also in:
io-uring, keyrings, linux-arch, linux-arm-kernel, linux-block, linux-fsdevel, linux-mips, linux-mm, linux-s390, linux-scsi, linux-security-module, linuxppc-dev, lkml, sparclinux
On Sun, Sep 20, 2020 at 9:28 PM Andy Lutomirski [off-list ref] wrote:
On Sun, Sep 20, 2020 at 12:23 PM Matthew Wilcox [off-list ref] wrote:quoted
On Sun, Sep 20, 2020 at 08:10:31PM +0100, Al Viro wrote:quoted
IMO it's much saner to mark those and refuse to touch them from io_uring...Simpler solution is to remove io_uring from the 32-bit syscall list. If you're a 32-bit process, you don't get to use io_uring. Would any real users actually care about that?We could go one step farther and declare that we're done adding *any* new compat syscalls :)
Would you also stop adding system calls to native 32-bit systems then?
On memory constrained systems (less than 2GB a.t.m.), there is still a
strong demand for running 32-bit user space, but all of the recent Arm
cores (after Cortex-A55) dropped the ability to run 32-bit kernels, so
that compat mode may eventually become the primary way to run
Linux on cheap embedded systems.
I don't think there is any chance we can realistically take away io_uring
from the 32-bit ABI any more now.
Arnd