Re: [RFC PATCH 3/7] riscv: Simplify MAXPHYSMEM config

From: Palmer Dabbelt
Date: Fri Apr 03 2020 - 11:53:17 EST


On Sun, 22 Mar 2020 04:00:24 PDT (-0700), alex@xxxxxxxx wrote:
Either the user specifies maximum physical memory size of 2GB or the
user lives with the system constraint which is 128GB in 64BIT for now.

Signed-off-by: Alexandre Ghiti <alex@xxxxxxxx>
---
arch/riscv/Kconfig | 20 ++++++--------------
1 file changed, 6 insertions(+), 14 deletions(-)

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 8e4b1cbcf2c2..a475c78e66bc 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -104,7 +104,7 @@ config PAGE_OFFSET
default 0xC0000000 if 32BIT && MAXPHYSMEM_2GB
default 0x80000000 if 64BIT && !MMU
default 0xffffffff80000000 if 64BIT && MAXPHYSMEM_2GB
- default 0xffffffe000000000 if 64BIT && MAXPHYSMEM_128GB
+ default 0xffffffe000000000 if 64BIT && !MAXPHYSMEM_2GB

config ARCH_FLATMEM_ENABLE
def_bool y
@@ -216,19 +216,11 @@ config MODULE_SECTIONS
bool
select HAVE_MOD_ARCH_SPECIFIC

-choice
- prompt "Maximum Physical Memory"
- default MAXPHYSMEM_2GB if 32BIT
- default MAXPHYSMEM_2GB if 64BIT && CMODEL_MEDLOW
- default MAXPHYSMEM_128GB if 64BIT && CMODEL_MEDANY
-
- config MAXPHYSMEM_2GB
- bool "2GiB"
- config MAXPHYSMEM_128GB
- depends on 64BIT && CMODEL_MEDANY
- bool "128GiB"
-endchoice
-
+config MAXPHYSMEM_2GB
+ bool "Maximum Physical Memory 2GiB"
+ default y if 32BIT
+ default y if 64BIT && CMODEL_MEDLOW
+ default n

config SMP
bool "Symmetric Multi-Processing"

I'm not sure this actually helps with anything, but if it's all going away then it's
fine. Originally the 2G/128G stuff was there to allow for larger VA spaces in
the future.