[PATCH v2 3/3] powerpc/64s/hash: disable subpage_prot syscall by default

[Nicholas Piggin]

The subpage_prot syscall was added for specialised system software
(Lx86) that has been discontinued for about 7 years, and is not thought
to be used elsewhere, so disable it by default.

Signed-off-by: Nicholas Piggin <npiggin at gmail.com>
---
 arch/powerpc/Kconfig                   | 7 +++++--
 arch/powerpc/configs/powernv_defconfig | 1 -
 arch/powerpc/configs/pseries_defconfig | 1 -
 3 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 9fa23eb320ff..04c6ca17661a 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -833,13 +833,16 @@ config FORCE_MAX_ZONEORDER
 	  this in mind when choosing a value for this option.
 
 config PPC_SUBPAGE_PROT
-	bool "Support setting protections for 4k subpages"
+	bool "Support setting protections for 4k subpages (subpage_prot syscall)"
+	default n
 	depends on PPC_BOOK3S_64 && PPC_64K_PAGES
 	help
-	  This option adds support for a system call to allow user programs
+	  This option adds support for system call to allow user programs
 	  to set access permissions (read/write, readonly, or no access)
 	  on the 4k subpages of each 64k page.
 
+	  If unsure, say N here.
+
 config PPC_COPRO_BASE
 	bool
 
diff --git a/arch/powerpc/configs/powernv_defconfig b/arch/powerpc/configs/powernv_defconfig
index 2de9aadf0f50..afc0dd73a1e6 100644
--- a/arch/powerpc/configs/powernv_defconfig
+++ b/arch/powerpc/configs/powernv_defconfig
@@ -64,7 +64,6 @@ CONFIG_HWPOISON_INJECT=m
 CONFIG_TRANSPARENT_HUGEPAGE=y
 CONFIG_DEFERRED_STRUCT_PAGE_INIT=y
 CONFIG_PPC_64K_PAGES=y
-CONFIG_PPC_SUBPAGE_PROT=y
 CONFIG_SCHED_SMT=y
 CONFIG_PM=y
 CONFIG_HOTPLUG_PCI=y
diff --git a/arch/powerpc/configs/pseries_defconfig b/arch/powerpc/configs/pseries_defconfig
index dfa4a726333b..894e8d85fb48 100644
--- a/arch/powerpc/configs/pseries_defconfig
+++ b/arch/powerpc/configs/pseries_defconfig
@@ -57,7 +57,6 @@ CONFIG_MEMORY_HOTREMOVE=y
 CONFIG_KSM=y
 CONFIG_TRANSPARENT_HUGEPAGE=y
 CONFIG_PPC_64K_PAGES=y
-CONFIG_PPC_SUBPAGE_PROT=y
 CONFIG_SCHED_SMT=y
 CONFIG_HOTPLUG_PCI=y
 CONFIG_HOTPLUG_PCI_RPA=m
-- 
2.23.0