On 7/10/24 11:55, Evan Green wrote:
On Mon, Jun 24, 2024 at 5:51 PM 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> Cc: stable@xxxxxxxxxxxxxxx --- V1 -> V2: - New patch V2 -> V3: - Split patch --- arch/riscv/kernel/traps_misaligned.c | 23 ++++++----------------- 1 file changed, 6 insertions(+), 17 deletions(-) diff --git a/arch/riscv/kernel/traps_misaligned.c b/arch/riscv/kernel/traps_misaligned.c index b62d5a2f4541..8fadbe00dd62 100644 --- a/arch/riscv/kernel/traps_misaligned.c +++ b/arch/riscv/kernel/traps_misaligned.c @@ -526,31 +526,17 @@ 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) { + 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; __asm__ __volatile__ ( " "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)) { - pr_crit("CPU misaligned accesses non homogeneous (expected all emulated)\n"); - while (true) - cpu_relax(); - }This chunk was meant to detect and refuse to run on a system where a heterogeneous CPU is hotplugged into a previously homogenous system. The commit message doesn't mention this change, how come you deleted it?
Sorry for the long wait. I do not remember why I removed this. Your right it shouldn't be removed, I added it back. Thanks, Jesse Taube
- - return misaligned_emu_detected; } bool check_unaligned_access_emulated_all_cpus(void) @@ -562,8 +548,11 @@ 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
