From 79b1feba54558bfb7df7c516dab29a7c9dba093c Mon Sep 17 00:00:00 2001
From: Atish Patra <atish.patra@wdc.com>
Date: Wed, 15 Jul 2020 16:30:06 -0700
Subject: [PATCH] RISC-V: Setup exception vector early
The trap vector is set only in trap_init which may be too late in some
cases. Early ioremap/efi spits many warning messages which may be useful.
Setup the trap vector early so that any warning/bug can be handled before
generic code invokes trap_init.
Signed-off-by: Atish Patra <atish.patra@wdc.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
---
arch/riscv/kernel/head.S | 10 ++++++++--
arch/riscv/kernel/smpboot.c | 2 +-
arch/riscv/kernel/traps.c | 8 +-------
3 files changed, 10 insertions(+), 10 deletions(-)
diff --git a/arch/riscv/kernel/head.S b/arch/riscv/kernel/head.S
index 7ed1b22950fd..d0c5c316e9bb 100644
--- a/arch/riscv/kernel/head.S
+++ b/arch/riscv/kernel/head.S
@@ -77,10 +77,16 @@ relocate:
csrw CSR_SATP, a0
.align 2
1:
- /* Set trap vector to spin forever to help debug */
- la a0, .Lsecondary_park
+ /* Set trap vector to exception handler */
+ la a0, handle_exception
csrw CSR_TVEC, a0
+ /*
+ * Set sup0 scratch register to 0, indicating to exception vector that
+ * we are presently executing in kernel.
+ */
+ csrw CSR_SCRATCH, zero
+
/* Reload the global pointer */
.option push
.option norelax
diff --git a/arch/riscv/kernel/smpboot.c b/arch/riscv/kernel/smpboot.c
index 403bd93412a4..47404d4ad721 100644
--- a/arch/riscv/kernel/smpboot.c
+++ b/arch/riscv/kernel/smpboot.c
@@ -154,10 +154,10 @@ 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);
+
/*
* Remote TLB flushes are ignored while the CPU is offline, so emit
* a local TLB flush right now just in case.
diff --git a/arch/riscv/kernel/traps.c b/arch/riscv/kernel/traps.c
index 7d95cce5e47c..ad14f4466d92 100644
--- a/arch/riscv/kernel/traps.c
+++ b/arch/riscv/kernel/traps.c
@@ -174,13 +174,7 @@ int is_valid_bugaddr(unsigned long pc)
}
#endif /* CONFIG_GENERIC_BUG */
+/* stvec & scratch is already set from head.S */
void trap_init(void)
{
- /*
- * 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);
}
--
2.49.0