openrisc: use shadow registers to save regs on exception
Previously, the area between 0x0-0x100 have been used as a "scratch"
memory area to temporarily store regs during exception entry. In a
multi-core environment, this will not work.
This change is to use shadow registers for nested context.
Currently only the "critical" temp load/stores are covered, the
EMERGENCY_PRINT ones are left as is (when they are used, it's game over
anyway), they need to be handled as well in the future.
Signed-off-by: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
Signed-off-by: Stafford Horne <shorne@gmail.com>
diff --git a/arch/openrisc/Kconfig b/arch/openrisc/Kconfig
index a0f2e4a..356dd67 100644
--- a/arch/openrisc/Kconfig
+++ b/arch/openrisc/Kconfig
@@ -124,6 +124,17 @@
Say N here if you know that your OpenRISC processor has
SPR_SR_DSX bit implemented. Say Y if you are unsure.
+config OPENRISC_HAVE_SHADOW_GPRS
+ bool "Support for shadow gpr files" if !SMP
+ default y if SMP
+ help
+ Say Y here if your OpenRISC processor features shadowed
+ register files. They will in such case be used as a
+ scratch reg storage on exception entry.
+
+ On SMP systems, this feature is mandatory.
+ On a unicore system it's safe to say N here if you are unsure.
+
config CMDLINE
string "Default kernel command string"
default ""
