[PATCH] Revert "ARM: 8433/1: add a VMSPLIT_3G_OPT config option"
Yisheng Xie
xieyisheng1 at huawei.com
Wed Jun 7 01:59:32 PDT 2017
This reverts commit 63ce446c9b5787a94ed875bab20772e1a2b3092f.
When enable VMSPLIT_3G_OPT, the PAGE_OFFSET will be 0xB0000000, and then
we will get the value "1" for TTBR1_SIZE(T1SZ) as the following MACRO:
#define TTBR1_SIZE (((PAGE_OFFSET >> 30) - 1) << 16)
which means TTBR1's range will be 0x80000000 to 0xffffffff, and it is
waster of VA [0x80000000, 0xB0000000). So it is better to use VMSPLIT_2G
instead, to achieve the goal "allows for 1GB systems to have their RAM
entirely mapped as low memory".
Meanwhile, It will trigger a bug of boot fail with CONFIG_ARM_LPAE=y,
which I reported:
https://patchwork.kernel.org/patch/9768573/
For ARM_LPAE only support 3:1, 2:2, 1:3 split of TTBR1, which mention in:
http://elinux.org/images/6/6a/Elce11_marinas.pdf - p16
Signed-off-by: Yisheng Xie <xieyisheng1 at huawei.com>
---
arch/arm/Kconfig | 3 ---
1 file changed, 3 deletions(-)
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 4c1a35f..5961835a 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -1415,8 +1415,6 @@ choice
config VMSPLIT_3G
bool "3G/1G user/kernel split"
- config VMSPLIT_3G_OPT
- bool "3G/1G user/kernel split (for full 1G low memory)"
config VMSPLIT_2G
bool "2G/2G user/kernel split"
config VMSPLIT_1G
@@ -1428,7 +1426,6 @@ config PAGE_OFFSET
default PHYS_OFFSET if !MMU
default 0x40000000 if VMSPLIT_1G
default 0x80000000 if VMSPLIT_2G
- default 0xB0000000 if VMSPLIT_3G_OPT
default 0xC0000000
config NR_CPUS
--
1.7.12.4
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