[PATCH] riscv: declare overflow_stack as exported from traps.c

[Ben Dooks <ben.dooks@codethink.co.uk>]

The percpu area overflow_stacks is exported from arch/riscv/kernel/traps.c
for use in the entry code, but is not declared anywhere. Add the relevant
declaration to arch/riscv/include/asm/stacktrace.h to silence the following
sparse warning:

arch/riscv/kernel/traps.c:395:1: warning: symbol '__pcpu_scope_overflow_stack' was not declared. Should it be static?

We don't add the stackinfo_get_overflow() call as for some of the other
architectures as this doesn't seem to be used yet, so just silence the
warning.

Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
---
 arch/riscv/include/asm/stacktrace.h | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/arch/riscv/include/asm/stacktrace.h b/arch/riscv/include/asm/stacktrace.h
index f7e8ef2418b9..b1495a7e06ce 100644
--- a/arch/riscv/include/asm/stacktrace.h
+++ b/arch/riscv/include/asm/stacktrace.h
@@ -21,4 +21,9 @@ static inline bool on_thread_stack(void)
 	return !(((unsigned long)(current->stack) ^ current_stack_pointer) & ~(THREAD_SIZE - 1));
 }
 
+
+#ifdef CONFIG_VMAP_STACK
+DECLARE_PER_CPU(unsigned long [OVERFLOW_STACK_SIZE/sizeof(long)], overflow_stack);
+#endif /* CONFIG_VMAP_STACK */
+
 #endif /* _ASM_RISCV_STACKTRACE_H */
-- 
2.37.2.352.g3c44437643