[PATCH 2/2] riscv: sbi: Accept SBI_ERR_ALREADY_AVAILABLE in sbi_hsm_hart_start

[artemiispatov at gmail.com]

From: Artemii Patov <artemiispatov at gmail.com>

Commit 8ac00cddc1a6 ("cpu/hotplug: Skip kick stage if the AP is stuck in
SYNC_STATE_ALIVE") changes the sync-state switching in kernel/cpu.c so
that a second AP bringup is no longer aborted. For that to work on
RISC-V, sbi_hsm_hart_start() must treat SBI_ERR_ALREADY_AVAILABLE as
a successful start: HSM returns this error when the hart is already
running.

Add the SBI_ERR_ALREADY_AVAILABLE -> -EALREADY mapping to
sbi_err_map_linux_errno() and treat -EALREADY as success in
sbi_hsm_hart_start(). Otherwise the error propagates through
arch_cpuhp_kick_ap_alive() to cpuhp_kick_ap_alive(), which fails the
retry and aborts the bringup.

Signed-off-by: Artemii Patov <artemiispatov at gmail.com>
---
 arch/riscv/include/asm/sbi.h    | 2 ++
 arch/riscv/kernel/cpu_ops_sbi.c | 7 ++++++-
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/arch/riscv/include/asm/sbi.h b/arch/riscv/include/asm/sbi.h
index 5725e0ca4dda..25016f1a9ad0 100644
--- a/arch/riscv/include/asm/sbi.h
+++ b/arch/riscv/include/asm/sbi.h
@@ -664,6 +664,8 @@ static inline int sbi_err_map_linux_errno(int err)
 		return -EINVAL;
 	case SBI_ERR_BAD_RANGE:
 		return -ERANGE;
+	case SBI_ERR_ALREADY_AVAILABLE:
+		return -EALREADY;
 	case SBI_ERR_INVALID_ADDRESS:
 		return -EFAULT;
 	case SBI_ERR_NO_SHMEM:
diff --git a/arch/riscv/kernel/cpu_ops_sbi.c b/arch/riscv/kernel/cpu_ops_sbi.c
index ee6e4b5cc39e..5acca3f4f8c0 100644
--- a/arch/riscv/kernel/cpu_ops_sbi.c
+++ b/arch/riscv/kernel/cpu_ops_sbi.c
@@ -26,12 +26,17 @@ static struct sbi_hart_boot_data boot_data[NR_CPUS];
 static int sbi_hsm_hart_start(unsigned long hartid, unsigned long saddr,
 			      unsigned long priv)
 {
+	int err;
 	struct sbiret ret;
 
 	ret = sbi_ecall(SBI_EXT_HSM, SBI_EXT_HSM_HART_START,
 			hartid, saddr, priv, 0, 0, 0);
 
-	return sbi_err_map_linux_errno(ret.error);
+	err = sbi_err_map_linux_errno(ret.error);
+	if (err == -EALREADY)
+		return 0;
+
+	return err;
 }
 
 #ifdef CONFIG_HOTPLUG_CPU
-- 
2.43.0