On Wed, Jul 17, 2024 at 11:07 AM Jesse Taube <jesse@xxxxxxxxxxxx> wrote:
>
> Originally, the check_unaligned_access_emulated_all_cpus function
> only checked the boot hart. This fixes the function to check all
> harts.
>
> Fixes: 71c54b3d169d ("riscv: report misaligned accesses emulation to hwprobe")
> Signed-off-by: Jesse Taube <jesse@xxxxxxxxxxxx>
> Reviewed-by: Charlie Jenkins <charlie@xxxxxxxxxxxx>
Reviewed-by: Evan Green <evan@xxxxxxxxxxxx>
> Cc: stable@xxxxxxxxxxxxxxx
> ---
> V1 -> V2:
> - New patch
> V2 -> V3:
> - Split patch
> V3 -> V4:
> - Re-add check for a system where a heterogeneous
> CPU is hotplugged into a previously homogenous
> system.
> V4 -> V5:
> - Change work_struct *unused to work_struct *work __always_unused
> ---
> arch/riscv/kernel/traps_misaligned.c | 14 +++++++-------
> 1 file changed, 7 insertions(+), 7 deletions(-)
>
> diff --git a/arch/riscv/kernel/traps_misaligned.c b/arch/riscv/kernel/traps_misaligned.c
> index b62d5a2f4541..9a1e94383d6d 100644
> --- a/arch/riscv/kernel/traps_misaligned.c
> +++ b/arch/riscv/kernel/traps_misaligned.c
> @@ -526,11 +526,11 @@ int handle_misaligned_store(struct pt_regs *regs)
> return 0;
> }
>
> -static bool check_unaligned_access_emulated(int cpu)
> +static void check_unaligned_access_emulated(struct work_struct *work __always_unused)
> {
> + int cpu = smp_processor_id();
> long *mas_ptr = per_cpu_ptr(&misaligned_access_speed, cpu);
> unsigned long tmp_var, tmp_val;
> - bool misaligned_emu_detected;
>
> *mas_ptr = RISCV_HWPROBE_MISALIGNED_UNKNOWN;
>
> @@ -538,19 +538,16 @@ static bool check_unaligned_access_emulated(int cpu)
> " "REG_L" %[tmp], 1(%[ptr])\n"
> : [tmp] "=r" (tmp_val) : [ptr] "r" (&tmp_var) : "memory");
>
> - misaligned_emu_detected = (*mas_ptr == RISCV_HWPROBE_MISALIGNED_EMULATED);
> /*
> * If unaligned_ctl is already set, this means that we detected that all
> * CPUS uses emulated misaligned access at boot time. If that changed
> * when hotplugging the new cpu, this is something we don't handle.
> */
> - if (unlikely(unaligned_ctl && !misaligned_emu_detected)) {
> + if (unlikely(unaligned_ctl && (*mas_ptr != RISCV_HWPROBE_MISALIGNED_EMULATED))) {
> pr_crit("CPU misaligned accesses non homogeneous (expected all emulated)\n");
> while (true)
> cpu_relax();
> }
> -
> - return misaligned_emu_detected;
> }
>
> bool check_unaligned_access_emulated_all_cpus(void)
> @@ -562,8 +559,11 @@ bool check_unaligned_access_emulated_all_cpus(void)
> * accesses emulated since tasks requesting such control can run on any
> * CPU.
> */
> + schedule_on_each_cpu(check_unaligned_access_emulated);
> +
> for_each_online_cpu(cpu)
> - if (!check_unaligned_access_emulated(cpu))
> + if (per_cpu(misaligned_access_speed, cpu)
> + != RISCV_HWPROBE_MISALIGNED_EMULATED)
> return false;
>
> unaligned_ctl = true;
> --
> 2.45.2
>
