[PATCH v4 6/6] RISC-V: Use IPIs for remote icache flush when possible

[Anup Patel]

If we have specialized interrupt controller (such as AIA IMSIC) which
allows supervisor mode to directly inject IPIs without any assistance
from M-mode or HS-mode then using such specialized interrupt controller,
we can do remote icache flushe directly from supervisor mode instead of
using the SBI RFENCE calls.

This patch extends remote icache flush functions to use supervisor mode
IPIs whenever direct supervisor mode IPIs.are supported by interrupt
controller.

Signed-off-by: Anup Patel <apatel at ventanamicro.com>
---
 arch/riscv/mm/cacheflush.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/arch/riscv/mm/cacheflush.c b/arch/riscv/mm/cacheflush.c
index 6cb7d96ad9c7..7c7e44aaf791 100644
--- a/arch/riscv/mm/cacheflush.c
+++ b/arch/riscv/mm/cacheflush.c
@@ -18,7 +18,7 @@ void flush_icache_all(void)
 {
 	local_flush_icache_all();
 
-	if (IS_ENABLED(CONFIG_RISCV_SBI))
+	if (IS_ENABLED(CONFIG_RISCV_SBI) && !riscv_use_ipi_for_rfence())
 		sbi_remote_fence_i(NULL);
 	else
 		on_each_cpu(ipi_remote_fence_i, NULL, 1);
@@ -66,7 +66,8 @@ void flush_icache_mm(struct mm_struct *mm, bool local)
 		 * with flush_icache_deferred().
 		 */
 		smp_mb();
-	} else if (IS_ENABLED(CONFIG_RISCV_SBI)) {
+	} else if (IS_ENABLED(CONFIG_RISCV_SBI) &&
+		   !riscv_use_ipi_for_rfence()) {
 		sbi_remote_fence_i(&others);
 	} else {
 		on_each_cpu_mask(&others, ipi_remote_fence_i, NULL, 1);
-- 
2.25.1