[PATCH v9 2/6] RISC-V: Scalar unaligned access emulated on hotplug CPUs

Jesse Taube
2024-08-20T15:27:41Z

The check_unaligned_access_emulated() function should have been called
during CPU hotplug to ensure that if all CPUs had emulated unaligned
accesses, the new CPU also does.

This patch adds the call to check_unaligned_access_emulated() in
the hotplug path.

Fixes: 55e0bf49a0d0 ("RISC-V: Probe misaligned access speed in parallel")
Signed-off-by: Jesse Taube <jesse@rivosinc.com>
Reviewed-by: Evan Green <evan@rivosinc.com>
Cc: stable@vger.kernel.org
---
V5 -> V6:
- New patch
V6 -> V7:
- No changes
V7 -> V8:
- Rebase onto fixes
V8 -> V9:
- No changes
---
arch/riscv/kernel/unaligned_access_speed.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/arch/riscv/kernel/unaligned_access_speed.c b/arch/riscv/kernel/unaligned_access_speed.c
index 160628a2116d..f3508cc54f91 100644
--- a/arch/riscv/kernel/unaligned_access_speed.c
+++ b/arch/riscv/kernel/unaligned_access_speed.c
@@ -191,6 +191,7 @@ static int riscv_online_cpu(unsigned int cpu)
if (per_cpu(misaligned_access_speed, cpu) != RISCV_HWPROBE_MISALIGNED_SCALAR_UNKNOWN)
goto exit;

+ check_unaligned_access_emulated(NULL);
buf = alloc_pages(GFP_KERNEL, MISALIGNED_BUFFER_ORDER);
if (!buf) {
pr_warn("Allocation failure, not measuring misaligned performance\n");