PT_GNU_STACK now that toolchains long support PT_GNU_STACK marking and
there's no need anymore to force modern programs into having all its
user mappings executable instead of only the stack and the PROT_EXEC
ones.
Disable that automatic READ_IMPLIES_EXEC forcing on x86-64 and
arm64.
Add tables documenting how READ_IMPLIES_EXEC is handled on x86-64, arm
and arm64.
This patch is needed to fix softlock up observed during stress test.
Backport from: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?h=v5.8-rc1&id=ac7b34218a0021bafd1d4c11c54217b930f516b0
Cherry-pick from: d6f5dfc8aa
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Tuan Phan <tphan@amperecomputing.com>
Tuan Phan