Currently, PAGE_OFFSET is hardcoded as 0x8000_0000, it works fine since
there's only one nommu platform in the mainline. However, there are
many cases where the (S)DRAM base address isn't 0x8000_0000, so remove
the hardcoding value, and introduce DRAM_BASE which will be set by
users during configuring. DRAM_BASE is 0x8000_0000 by default.
Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
---
arch/riscv/Kconfig | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 7895c77545f1..b4af1df86352 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -247,10 +247,16 @@ config MMU
Select if you want MMU-based virtualised addressing space
support by paged memory management. If unsure, say 'Y'.
+if !MMU
+config DRAM_BASE
+ hex '(S)DRAM Base Address'
+ default 0x80000000
+endif
+
config PAGE_OFFSET
hex
default 0xC0000000 if 32BIT && MMU
- default 0x80000000 if !MMU
+ default DRAM_BASE if !MMU
default 0xff60000000000000 if 64BIT
config KASAN_SHADOW_OFFSET
--
2.43.0On 10/04/2024 16:23, Jisheng Zhang wrote: > Currently, PAGE_OFFSET is hardcoded as 0x8000_0000, it works fine since > there's only one nommu platform in the mainline. However, there are > many cases where the (S)DRAM base address isn't 0x8000_0000, so remove > the hardcoding value, and introduce DRAM_BASE which will be set by Hi Jisheng, Typo: s/harcoding/hardcoded > users during configuring. DRAM_BASE is 0x8000_0000 by default. > > Signed-off-by: Jisheng Zhang <jszhang@kernel.org> > --- > arch/riscv/Kconfig | 8 +++++++- > 1 file changed, 7 insertions(+), 1 deletion(-) > > diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig > index 7895c77545f1..b4af1df86352 100644 > --- a/arch/riscv/Kconfig > +++ b/arch/riscv/Kconfig > @@ -247,10 +247,16 @@ config MMU > Select if you want MMU-based virtualised addressing space > support by paged memory management. If unsure, say 'Y'. > > +if !MMU > +config DRAM_BASE > + hex '(S)DRAM Base Address' > + default 0x80000000 > +endif I'm not sure but it feels odd to have this at top level config menu. Maybe it would make more sense for this to be located under the "Platform Type" section ? Thanks, Clément > + > config PAGE_OFFSET > hex > default 0xC0000000 if 32BIT && MMU > - default 0x80000000 if !MMU > + default DRAM_BASE if !MMU > default 0xff60000000000000 if 64BIT > > config KASAN_SHADOW_OFFSET
On 10/04/2024 17:30, Clément Léger wrote: > > > On 10/04/2024 16:23, Jisheng Zhang wrote: >> Currently, PAGE_OFFSET is hardcoded as 0x8000_0000, it works fine since >> there's only one nommu platform in the mainline. However, there are >> many cases where the (S)DRAM base address isn't 0x8000_0000, so remove >> the hardcoding value, and introduce DRAM_BASE which will be set by > > Hi Jisheng, > > Typo: s/harcoding/hardcoded > >> users during configuring. DRAM_BASE is 0x8000_0000 by default. >> >> Signed-off-by: Jisheng Zhang <jszhang@kernel.org> >> --- >> arch/riscv/Kconfig | 8 +++++++- >> 1 file changed, 7 insertions(+), 1 deletion(-) >> >> diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig >> index 7895c77545f1..b4af1df86352 100644 >> --- a/arch/riscv/Kconfig >> +++ b/arch/riscv/Kconfig >> @@ -247,10 +247,16 @@ config MMU >> Select if you want MMU-based virtualised addressing space >> support by paged memory management. If unsure, say 'Y'. >> >> +if !MMU >> +config DRAM_BASE >> + hex '(S)DRAM Base Address' >> + default 0x80000000 >> +endif > > I'm not sure but it feels odd to have this at top level config menu. > Maybe it would make more sense for this to be located under the > "Platform Type" section ? > > Thanks, > > Clément > >> + >> config PAGE_OFFSET >> hex >> default 0xC0000000 if 32BIT && MMU >> - default 0x80000000 if !MMU >> + default DRAM_BASE if !MMU >> default 0xff60000000000000 if 64BIT By the way, you should probably rebase that on top of Samuel's work [1] in order to support !MMU is S-mode. Thanks, Clément Link: https://lore.kernel.org/lkml/20240227003630.3634533-5-samuel.holland@sifive.com/ [1] >> >> config KASAN_SHADOW_OFFSET
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