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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 v2 13/15] powerpc/kconfig: make _etext and data areas alignment configurable on Book3s 32
Date: Thu, 10 Jan 2019 15:12:05 +0000 (UTC)	[thread overview]
Message-ID: <c3bb3c841b23d14732144b2fa80dc43587213fac.1547132681.git.christophe.leroy@c-s.fr> (raw)
In-Reply-To: <cover.1547132681.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 1828fefd99f9..3f6365f29c65 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -731,16 +731,44 @@ 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:[~2019-01-10 15:35 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-01-10 15:11 [PATCH v2 00/15] powerpc/32s: Use BATs/LTLBs for STRICT_KERNEL_RWX Christophe Leroy
2019-01-10 15:11 ` [PATCH v2 01/15] powerpc/mm/32: add base address to mmu_mapin_ram() Christophe Leroy
2019-01-10 15:11 ` [PATCH v2 02/15] powerpc/mm/32s: rework mmu_mapin_ram() Christophe Leroy
2019-01-10 15:11 ` [PATCH v2 03/15] powerpc/mm/32s: use generic mmu_mapin_ram() for all blocks Christophe Leroy
2019-01-10 15:11 ` [PATCH v2 04/15] powerpc/32: always populate page tables for Abatron BDI Christophe Leroy
2019-01-10 15:11 ` [PATCH v2 05/15] powerpc/wii: remove wii_mmu_mapin_mem2() Christophe Leroy
2019-01-10 15:11 ` [PATCH v2 06/15] powerpc/mm/32s: use _PAGE_EXEC in setbat() Christophe Leroy
2019-01-10 15:11 ` [PATCH v2 07/15] powerpc/mm/32s: add setibat() clearibat() and update_bats() Christophe Leroy
2019-01-10 15:11 ` [PATCH v2 08/15] powerpc/32: add helper to write into segment registers Christophe Leroy
2019-01-10 15:11 ` [PATCH v2 09/15] powerpc/mmu: add is_strict_kernel_rwx() helper Christophe Leroy
2019-01-10 15:11 ` [PATCH v2 10/15] powerpc/kconfig: define PAGE_SHIFT inside Kconfig Christophe Leroy
2019-01-10 15:12 ` [PATCH v2 11/15] powerpc/kconfig: define CONFIG_DATA_SHIFT and CONFIG_ETEXT_SHIFT Christophe Leroy
2019-01-10 15:12 ` [PATCH v2 12/15] powerpc/mm/32s: Use BATs for STRICT_KERNEL_RWX Christophe Leroy
2019-01-10 15:12 ` Christophe Leroy [this message]
2019-01-10 15:12 ` [PATCH v2 14/15] powerpc/8xx: don't disable large TLBs with CONFIG_STRICT_KERNEL_RWX Christophe Leroy
2019-01-10 15:12 ` [PATCH v2 15/15] powerpc/kconfig: make _etext and data areas alignment configurable on 8xx Christophe Leroy
2019-01-13 18:16 ` [PATCH v2 00/15] powerpc/32s: Use BATs/LTLBs for STRICT_KERNEL_RWX Jonathan Neuschäfer
2019-01-13 19:43   ` Christophe Leroy
2019-01-13 21:02     ` Jonathan Neuschäfer
2019-01-14 18:23       ` Christophe Leroy
2019-01-15  0:33         ` Jonathan Neuschäfer
2019-01-15  6:51           ` Christophe Leroy
2019-01-15 10:22             ` Michael Ellerman
2019-01-15 10:57               ` Christophe Leroy
2019-02-20 13:23                 ` Michael Ellerman
2019-02-20 15:30                   ` Christophe Leroy
2019-01-16  0:35             ` Jonathan Neuschäfer
2019-01-16  6:55               ` Christophe Leroy
2019-01-16 13:16                 ` Jonathan Neuschäfer
2019-01-16 13:34                   ` Christophe Leroy
2019-01-16 23:48                     ` Jonathan Neuschäfer
2019-01-17 10:14                       ` Christophe Leroy

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