On Wed, Jul 17, 2024 at 11:07 AM Jesse Taube jesse@rivosinc.com 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@rivosinc.com Reviewed-by: Charlie Jenkins charlie@rivosinc.com

Reviewed-by: Evan Green evan@rivosinc.com

Cc: stable@vger.kernel.org

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