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Subject[PATCH] riscv: Setup exception vector for K210 properly
Date
Exception vector is missing on nommu platform and it is a big issue.
This patch is tested in Sipeed MAIX Bit Dev Board.

Fixes: 79b1feba5455 ("RISC-V: Setup exception vector early")
Signed-off-by: Qiu Wenbo <qiuwenbo@phytium.com.cn>
---
arch/riscv/kernel/smpboot.c | 1 +
arch/riscv/kernel/traps.c | 11 ++++++++++-
2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/arch/riscv/kernel/smpboot.c b/arch/riscv/kernel/smpboot.c
index 356825a57551..23cde0ceb39d 100644
--- a/arch/riscv/kernel/smpboot.c
+++ b/arch/riscv/kernel/smpboot.c
@@ -154,6 +154,7 @@ asmlinkage __visible void smp_callin(void)
mmgrab(mm);
current->active_mm = mm;

+ trap_init();
notify_cpu_starting(curr_cpuid);
update_siblings_masks(curr_cpuid);
set_cpu_online(curr_cpuid, 1);
diff --git a/arch/riscv/kernel/traps.c b/arch/riscv/kernel/traps.c
index ad14f4466d92..a390239818ae 100644
--- a/arch/riscv/kernel/traps.c
+++ b/arch/riscv/kernel/traps.c
@@ -174,7 +174,16 @@ int is_valid_bugaddr(unsigned long pc)
}
#endif /* CONFIG_GENERIC_BUG */

-/* stvec & scratch is already set from head.S */
+/* stvec & scratch is already set from head.S when mmu is enabled */
void trap_init(void)
{
+#ifndef CONFIG_MMU
+ /*
+ * Set sup0 scratch register to 0, indicating to exception vector
+ * that we are presently executing in the kernel
+ */
+ csr_write(CSR_SCRATCH, 0);
+ /* Set the exception vector address */
+ csr_write(CSR_TVEC, &handle_exception);
+#endif
}
--
2.28.0
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