manual: Add description of AArch64-specific pkey flags

Describe AArch64 specific flags PKEY_DISABLE_READ and PKEY_DISABLE_EXECUTE that
are available on AArch64 systems with enabled Stage 1 permission overlays
feature introduced in Armv8.9 / 9.4 (FEAT_S1POE).

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
This commit is contained in:
Yury Khrustalev 2024-11-20 11:20:33 +00:00 committed by Wilco Dijkstra
parent f4d00dd60d
commit 47311cca31

View File

@ -3261,6 +3261,12 @@ the page protection flags are applied. Otherwise, @var{access_restrictions} is
a combination of the following flags:
@vtable @code
@item PKEY_DISABLE_READ
@standards{Linux, sys/mman.h}
Subsequent attempts to read from memory with the specified protection
key will fault. At present only AArch64 platforms with enabled Stage 1
permission overlays feature support this type of restriction.
@item PKEY_DISABLE_WRITE
@standards{Linux, sys/mman.h}
Subsequent attempts to write to memory with the specified protection
@ -3269,7 +3275,15 @@ key will fault.
@item PKEY_DISABLE_ACCESS
@standards{Linux, sys/mman.h}
Subsequent attempts to write to or read from memory with the specified
protection key will fault.
protection key will fault. On AArch64 platforms with enabled Stage 1
permission overlays feature this restriction value has the same effect
as combination of @code{PKEY_DISABLE_READ} and @code{PKEY_DISABLE_WRITE}.
@item PKEY_DISABLE_EXECUTE
@standards{Linux, sys/mman.h}
Subsequent attempts to execute from memory with the specified protection
key will fault. At present only AArch64 platforms with enabled Stage 1
permission overlays feature support this type of restriction.
@end vtable
Operations not specified as flags are not restricted. In particular,