[PATCH v5 11/16] powerpc/kconfig: define CONFIG_DATA_SHIFT and CONFIG_ETEXT_SHIFT

Christophe Leroy
2019-02-21T19:09:15Z

CONFIG_STRICT_KERNEL_RWX requires a special alignment
for DATA for some subarches. Today it is just defined
as an #ifdef in vmlinux.lds.S

In order to get more flexibility, this patch moves the
definition of this alignment in Kconfig

On some subarches, CONFIG_STRICT_KERNEL_RWX will
require a special alignment of _etext.

This patch also adds a configuration item for it in Kconfig

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
---
arch/powerpc/Kconfig | 9 +++++++++
arch/powerpc/kernel/vmlinux.lds.S | 9 +++------
2 files changed, 12 insertions(+), 6 deletions(-)

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 417e52a27f63..edef40a2b446 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -725,6 +725,15 @@ config THREAD_SHIFT
Used to define the stack size. The default is almost always what you
want. Only change this if you know what you are doing.

+config ETEXT_SHIFT
+ int
+ default PPC_PAGE_SHIFT
+
+config DATA_SHIFT
+ int
+ default 24 if STRICT_KERNEL_RWX && PPC64
+ default PPC_PAGE_SHIFT
+
config FORCE_MAX_ZONEORDER
int "Maximum zone order"
range 8 9 if PPC64 && PPC_64K_PAGES
diff --git a/arch/powerpc/kernel/vmlinux.lds.S b/arch/powerpc/kernel/vmlinux.lds.S
index c3efb972c8c1..060a1acd7c6d 100644
--- a/arch/powerpc/kernel/vmlinux.lds.S
+++ b/arch/powerpc/kernel/vmlinux.lds.S
@@ -12,11 +12,8 @@
#include <asm/cache.h>
#include <asm/thread_info.h>

-#if defined(CONFIG_STRICT_KERNEL_RWX) && !defined(CONFIG_PPC32)
-#define STRICT_ALIGN_SIZE (1 << 24)
-#else
-#define STRICT_ALIGN_SIZE PAGE_SIZE
-#endif
+#define STRICT_ALIGN_SIZE (1 << CONFIG_DATA_SHIFT)
+#define ETEXT_ALIGN_SIZE (1 << CONFIG_ETEXT_SHIFT)

ENTRY(_stext)

@@ -131,7 +128,7 @@ SECTIONS

} :kernel

- . = ALIGN(PAGE_SIZE);
+ . = ALIGN(ETEXT_ALIGN_SIZE);
_etext = .;
PROVIDE32 (etext = .);

--
2.13.3