[PATCH v3 14/16] powerpc/kconfig: make _etext and data areas alignment configurable on Book3s 32
From: Christophe Leroy <hidden>
Date: 2019-02-20 17:29:48
Also in:
lkml
Subsystem:
linux for powerpc (32-bit and 64-bit), the rest · Maintainers:
Madhavan Srinivasan, Michael Ellerman, Linus Torvalds
Depending on the number of available BATs for mapping the different kernel areas, it might be needed to increase the alignment of _etext and/or of data areas. This patchs allows the user to do it via Kconfig. Signed-off-by: Christophe Leroy <redacted> --- arch/powerpc/Kconfig | 32 ++++++++++++++++++++++++++++++-- 1 file changed, 30 insertions(+), 2 deletions(-)
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 640a7cfba9d0..20c4e3a62b90 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig@@ -725,16 +725,44 @@ 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_BOOL + bool "Set custom etext alignment" if STRICT_KERNEL_RWX && PPC_BOOK3S_32 + depends on ADVANCED_OPTIONS + help + This option allows you to set the kernel end of text alignment. When + RAM is mapped by blocks, the alignment needs to fit the size and + number of possible blocks. The default should be OK for most configs. + + Say N here unless you know what you are doing. + config ETEXT_SHIFT - int + int "_etext shift" if ETEXT_SHIFT_BOOL + range 17 28 if STRICT_KERNEL_RWX && PPC_BOOK3S_32 default 17 if STRICT_KERNEL_RWX && PPC_BOOK3S_32 default PPC_PAGE_SHIFT + help + On Book3S 32 (603+), IBATs are used to map kernel text. + Smaller is the alignment, greater is the number of necessary IBATs. + +config DATA_SHIFT_BOOL + bool "Set custom data alignment" if STRICT_KERNEL_RWX && PPC_BOOK3S_32 + depends on ADVANCED_OPTIONS + help + This option allows you to set the kernel data alignment. When + RAM is mapped by blocks, the alignment needs to fit the size and + number of possible blocks. The default should be OK for most configs. + + Say N here unless you know what you are doing. config DATA_SHIFT - int + int "Data shift" if DATA_SHIFT_BOOL default 24 if STRICT_KERNEL_RWX && PPC64 + range 17 28 if STRICT_KERNEL_RWX && PPC_BOOK3S_32 default 22 if STRICT_KERNEL_RWX && PPC_BOOK3S_32 default PPC_PAGE_SHIFT + help + On Book3S 32 (603+), DBATs are used to map kernel text and rodata RO. + Smaller is the alignment, greater is the number of necessary DBATs. config FORCE_MAX_ZONEORDER int "Maximum zone order"
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2.13.3