RISC-V: Fix maximum allowed phsyical memory for RV32

Linux kernel can only map 1GB of address space for RV32 as the page offset
is set to 0xC0000000. The current description in the Kconfig is confusing
as it indicates that RV32 can support 2GB of physical memory. That is
simply not true for current kernel. In future, a 2GB split support can be
added to allow 2GB physical address space.

Reviewed-by: Anup Patel <anup@brainfault.org>
Signed-off-by: Atish Patra <atish.patra@wdc.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 81b76d4..e9e2c1f 100644 (file)
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -137,7 +137,7 @@ config PA_BITS
 
 config PAGE_OFFSET
        hex
-       default 0xC0000000 if 32BIT && MAXPHYSMEM_2GB
+       default 0xC0000000 if 32BIT && MAXPHYSMEM_1GB
        default 0x80000000 if 64BIT && !MMU
        default 0xffffffff80000000 if 64BIT && MAXPHYSMEM_2GB
        default 0xffffffe000000000 if 64BIT && MAXPHYSMEM_128GB
@@ -247,10 +247,12 @@ config MODULE_SECTIONS
 
 choice
        prompt "Maximum Physical Memory"
-       default MAXPHYSMEM_2GB if 32BIT
+       default MAXPHYSMEM_1GB if 32BIT
        default MAXPHYSMEM_2GB if 64BIT && CMODEL_MEDLOW
        default MAXPHYSMEM_128GB if 64BIT && CMODEL_MEDANY
 
+       config MAXPHYSMEM_1GB
+               bool "1GiB"
        config MAXPHYSMEM_2GB
                bool "2GiB"
        config MAXPHYSMEM_128GB