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From: Christophe Leroy <christophe.leroy@c-s.fr>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	Paul Mackerras <paulus@samba.org>,
	Michael Ellerman <mpe@ellerman.id.au>,
	 j.neuschaefer@gmx.net
Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org
Subject: [PATCH v5 14/16] powerpc/kconfig: make _etext and data areas alignment configurable on Book3s 32
Date: Thu, 21 Feb 2019 19:08:50 +0000 (UTC)	[thread overview]
Message-ID: <7007a81052e383f15526153c18f8fd73f45da252.1550775950.git.christophe.leroy@c-s.fr> (raw)
In-Reply-To: <cover.1550775950.git.christophe.leroy@c-s.fr>

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 <christophe.leroy@c-s.fr>
---
 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"
-- 
2.13.3


  parent reply	other threads:[~2019-02-21 19:33 UTC|newest]

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-02-21 19:08 [PATCH v5 00/16] powerpc/32: Use BATs/LTLBs for STRICT_KERNEL_RWX Christophe Leroy
2019-02-21 19:08 ` [PATCH v5 01/16] powerpc/wii: properly disable use of BATs when requested Christophe Leroy
2019-02-26  3:27   ` [v5, " Michael Ellerman
2019-02-21 19:08 ` [PATCH v5 02/16] powerpc/mm/32: add base address to mmu_mapin_ram() Christophe Leroy
2019-02-21 19:08 ` [PATCH v5 03/16] powerpc/mm/32s: rework mmu_mapin_ram() Christophe Leroy
2019-02-21 19:08 ` [PATCH v5 04/16] powerpc/mm/32s: use generic mmu_mapin_ram() for all blocks Christophe Leroy
2019-02-21 19:08 ` [PATCH v5 05/16] powerpc/32: always populate page tables for Abatron BDI Christophe Leroy
2019-02-21 19:08 ` [PATCH v5 06/16] powerpc/wii: remove wii_mmu_mapin_mem2() Christophe Leroy
2019-02-21 19:08 ` [PATCH v5 07/16] powerpc/mm/32s: use _PAGE_EXEC in setbat() Christophe Leroy
2019-02-21 19:08 ` [PATCH v5 08/16] powerpc/32: add helper to write into segment registers Christophe Leroy
2019-02-21 19:08 ` [PATCH v5 09/16] powerpc/mmu: add is_strict_kernel_rwx() helper Christophe Leroy
2019-02-21 19:08 ` [PATCH v5 10/16] powerpc/kconfig: define PAGE_SHIFT inside Kconfig Christophe Leroy
2019-02-21 19:08 ` [PATCH v5 11/16] powerpc/kconfig: define CONFIG_DATA_SHIFT and CONFIG_ETEXT_SHIFT Christophe Leroy
2019-02-21 19:08 ` [PATCH v5 12/16] powerpc/mm/32s: add setibat() clearibat() and update_bats() Christophe Leroy
2019-02-21 19:08 ` [PATCH v5 13/16] powerpc/mm/32s: Use BATs for STRICT_KERNEL_RWX Christophe Leroy
2019-06-15 11:23   ` Andreas Schwab
2019-06-15 13:22     ` Christophe Leroy
2019-06-16  8:20     ` christophe leroy
2019-06-16  9:29       ` Andreas Schwab
2019-06-16 10:13       ` Andreas Schwab
2019-06-15 12:28   ` Andreas Schwab
2019-06-16  8:01     ` christophe leroy
2019-06-16  8:45       ` Andreas Schwab
2019-06-15 12:47   ` [PATCH] powerpc/mm/32s: only use MMU to mark initmem NX if STRICT_KERNEL_RWX Andreas Schwab
2019-06-15 13:25     ` Christophe Leroy
2019-06-15 14:36       ` Andreas Schwab
2019-06-16  8:06         ` christophe leroy
2019-06-17 21:22   ` [PATCH] powerpc/mm/32s: fix condition that is always true Andreas Schwab
2019-06-17 21:47     ` Christophe Leroy
2019-06-30  8:37     ` Michael Ellerman
2019-02-21 19:08 ` Christophe Leroy [this message]
2019-02-21 19:08 ` [PATCH v5 15/16] powerpc/8xx: don't disable large TLBs with CONFIG_STRICT_KERNEL_RWX Christophe Leroy
2019-02-21 19:08 ` [PATCH v5 16/16] powerpc/kconfig: make _etext and data areas alignment configurable on 8xx Christophe Leroy

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