[PATCH v3 16/19] arm64: text replication: add Kconfig

[Hao Jia]

From: "Russell King (Oracle)" <rmk+kernel at armlinux.org.uk>

Add the Kconfig symbol for kernel text replication. This unfortunately
requires KASAN and kernel text randomisation options to be disabled at
the moment.

Currently, we do not support CONFIG_ARM64_16K_PAGES and
CONFIG_PGTABLE_LEVLS=4, because PGDIR_SIZE is 128T,
which is too large to allow the kernel text to
exclusively occupy an L0 page table entry.

Signed-off-by: Russell King (Oracle) <rmk+kernel at armlinux.org.uk>
---
 arch/arm64/Kconfig | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 8f6cf1221b6a..a9dfe6e0006a 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -163,7 +163,7 @@ config ARM64
 	select HAVE_ARCH_HUGE_VMAP
 	select HAVE_ARCH_JUMP_LABEL
 	select HAVE_ARCH_JUMP_LABEL_RELATIVE
-	select HAVE_ARCH_KASAN if !(ARM64_16K_PAGES && ARM64_VA_BITS_48)
+	select HAVE_ARCH_KASAN if !(ARM64_16K_PAGES && ARM64_VA_BITS_48 && !REPLICATE_KTEXT)
 	select HAVE_ARCH_KASAN_VMALLOC if HAVE_ARCH_KASAN
 	select HAVE_ARCH_KASAN_SW_TAGS if HAVE_ARCH_KASAN
 	select HAVE_ARCH_KASAN_HW_TAGS if (HAVE_ARCH_KASAN && ARM64_MTE)
@@ -1443,6 +1443,13 @@ config NODES_SHIFT
 	  Specify the maximum number of NUMA Nodes available on the target
 	  system.  Increases memory reserved to accommodate various tables.
 
+config REPLICATE_KTEXT
+	bool "Replicate kernel text across numa nodes"
+	depends on NUMA && !(ARM64_16K_PAGES && ARM64_VA_BITS_48)
+	help
+	  Say Y here to enable replicating the kernel text across multiple
+	  nodes in a NUMA cluster.  This trades memory for speed.
+
 source "kernel/Kconfig.hz"
 
 config ARCH_SPARSEMEM_ENABLE
@@ -2161,6 +2168,7 @@ config RELOCATABLE
 
 config RANDOMIZE_BASE
 	bool "Randomize the address of the kernel image"
+	depends on !REPLICATE_KTEXT
 	select RELOCATABLE
 	help
 	  Randomizes the virtual address at which the kernel image is
-- 
2.20.1