lkml.org 
[lkml]   [2014]   [Nov]   [18]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Subject[PATCH RFC 2/3] ARM: enable TTBR0/TTBR1 split in short mode
From
Date
This feature was partially implemented long time ago. All cpus load
swapper_pg_dir into TTBR1 since commit d427958a46af24f75d0017c45eadd172273bbf33
("ARM: 6942/1: mm: make TTBR1 always point to swapper_pg_dir on ARMv6/7").
But TTBRx split is never been enabled in TTBCR.

This patch enables TTBRx split for 2Gb/2Gb and 1Gb/3Gb combinations.
Area covered by TTBR0 must be power of two, thus 3Gb/1Gb mode is unsupported.

Signed-off-by: Konstantin Khlebnikov <k.khlebnikov@samsung.com>
---
arch/arm/include/asm/pgtable-2level-hwdef.h | 13 +++++++++++++
1 file changed, 13 insertions(+)

diff --git a/arch/arm/include/asm/pgtable-2level-hwdef.h b/arch/arm/include/asm/pgtable-2level-hwdef.h
index c2ed1fa..605652c 100644
--- a/arch/arm/include/asm/pgtable-2level-hwdef.h
+++ b/arch/arm/include/asm/pgtable-2level-hwdef.h
@@ -90,6 +90,19 @@

#define PHYS_MASK (~0UL)

+/*
+ * TTBR0/TTBR1 split (PAGE_OFFSET):
+ * 0x40000000: TTBCR.N = 2
+ * 0x80000000: TTBCR.N = 1
+ * 0xc0000000: TTBCR.N = 0 (not used)
+ */
+
+#ifdef CONFIG_VMSPLIT_1G
+#define TTBR1_SIZE 2
+#elif defined CONFIG_VMSPLIT_2G
+#define TTBR1_SIZE 1
+#elif defined CONFIG_VMSPLIT_3G
#define TTBR1_SIZE 0
+#endif

#endif


\
 
 \ /
  Last update: 2014-11-18 18:21    [W:1.873 / U:0.140 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site