selftest mm/mseal read-only elf memory segment

Sealing read-only of elf mapping so it can't be changed by mprotect.

[jeffxu@chromium.org: style change]
  Link: https://lkml.kernel.org/r/20240416220944.2481203-2-jeffxu@chromium.org
[amer.shanawany@gmail.com: fix linker error for inline function]
  Link: https://lkml.kernel.org/r/20240420202346.546444-1-amer.shanawany@gmail.com
[jeffxu@chromium.org: fix compile warning]
  Link: https://lkml.kernel.org/r/20240420003515.345982-2-jeffxu@chromium.org
[jeffxu@chromium.org: fix arm build]
  Link: https://lkml.kernel.org/r/20240502225331.3806279-2-jeffxu@chromium.org
Link: https://lkml.kernel.org/r/20240415163527.626541-6-jeffxu@chromium.org
Signed-off-by: Jeff Xu <jeffxu@chromium.org>
Signed-off-by: Amer Al Shanawany <amer.shanawany@gmail.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Guenter Roeck <groeck@chromium.org>
Cc: Jann Horn <jannh@google.com>
Cc: Jeff Xu <jeffxu@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Jorge Lucangeli Obes <jorgelo@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Muhammad Usama Anjum <usama.anjum@collabora.com>
Cc: Pedro Falcato <pedro.falcato@gmail.com>
Cc: Stephen Röttger <sroettger@google.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Amer Al Shanawany <amer.shanawany@gmail.com>
Cc: Javier Carrasco <javier.carrasco.cruz@gmail.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Author: peaktocreek

tools/testing/selftests/mm/.gitignore

@@ -48,3 +48,4 @@ va_high_addr_switch
 hugetlb_fault_after_madv
 hugetlb_madv_vs_map
 mseal_test
+seal_elf

tools/testing/selftests/mm/Makefile

@@ -60,6 +60,7 @@ TEST_GEN_FILES += mrelease_test
 TEST_GEN_FILES += mremap_dontunmap
 TEST_GEN_FILES += mremap_test
 TEST_GEN_FILES += mseal_test
+TEST_GEN_FILES += seal_elf
 TEST_GEN_FILES += on-fault-limit
 TEST_GEN_FILES += pagemap_ioctl
 TEST_GEN_FILES += thuge-gen