On Thu, Jul 11, 2024 at 05:58:42PM -0400, Jesse Taube 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 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.

---

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..1a1bb41472ea 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 *unused)

Small change, can you give this a different name like "work" and instead give it the attribute "__always_unused" like:

struct work_struct *work __always_unused

Otherwise,

Reviewed-by: Charlie Jenkins charlie@rivosinc.com

{

• 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