RISC-V: Scalar unaligned access emulated on hotplug CPUs

BugLink: https://bugs.launchpad.net/bugs/2101915

commit 9c528b5f7927b857b40f3c46afbc869827af3c94 upstream.

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: 55e0bf49a0 ("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
Link: https://lore.kernel.org/r/20241017-jesse_unaligned_vector-v10-2-5b33500160f8@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[koichiroden: applied to an older path due to missing commits:
f413aae96cda ("riscv: Set unaligned access speed at compile time")]
Signed-off-by: Koichiro Den <koichiro.den@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>

This commit is contained in:

Jesse Taube

2025-03-11 08:51:19 +09:00

committed by

Stefan Bader

parent b008003fba

commit 4924e09a46

1 changed files with 1 additions and 0 deletions

									
										arch/riscv/kernel/cpufeature.c
									
		+1
		
												View File
												
				@@ -903,6 +903,7 @@ static int riscv_online_cpu(unsigned int cpu)

					if (per_cpu(misaligned_access_speed, cpu) != RISCV_HWPROBE_MISALIGNED_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");