Re: [PATCH] acpi/prmt: find block with specific type

Zhang, Rui
2024-08-21T03:20:54Z

On Thu, 2024-08-01 at 09:48 +0800, KobaK wrote:
> PRMT needs to find the correct type of block to
> translate the PA-VA mapping for EFI runtime services.
>
> The issue arises because the PRMT is finding a block of type
> EFI_CONVENTIONAL_MEMORY,
> which is not appropriate for runtime services as described in Section
> 2.2.2 (Runtime
> Services) of the UEFI Specification [1]. Since the PRM handler is a
> type of runtime
> service, this causes an exception when the PRM handler is called.
>
Too many characters in one line.
https://docs.kernel.org/process/submitting-patches.html#the-canonical-patch-format

>     [Firmware Bug]: Unable to handle paging request in EFI runtime
> service
>     WARNING: CPU: 22 PID: 4330 at drivers/firmware/efi/runtime-
> wrappers.c:341 __efi_queue_work+0x11c/0x170
>     Call trace:
>       __efi_queue_work+0x11c/0x170
>       efi_call_acpi_prm_handler+0x68/0xd0
>       acpi_platformrt_space_handler+0x198/0x258
>       acpi_ev_address_space_dispatch+0x144/0x388
>       acpi_ex_access_region+0x9c/0x118
>       acpi_ex_write_serial_bus+0xc4/0x218
>       acpi_ex_write_data_to_field+0x168/0x218
>       acpi_ex_store_object_to_node+0x1a8/0x258
>       acpi_ex_store+0xec/0x330
>       acpi_ex_opcode_1A_1T_1R+0x15c/0x618
>       acpi_ds_exec_end_op+0x274/0x548
>       acpi_ps_parse_loop+0x10c/0x6b8
>       acpi_ps_parse_aml+0x140/0x3b0
>       acpi_ps_execute_method+0x12c/0x2a0
>       acpi_ns_evaluate+0x210/0x310
>       acpi_evaluate_object+0x178/0x358
>       acpi_proc_write+0x1a8/0x8a0 [acpi_call]
>       proc_reg_write+0xcc/0x150
>       vfs_write+0xd8/0x380
>       ksys_write+0x70/0x120
>       __arm64_sys_write+0x24/0x48
>       invoke_syscall.constprop.0+0x80/0xf8
>       do_el0_svc+0x50/0x110
>       el0_svc+0x48/0x1d0
>       el0t_64_sync_handler+0x15c/0x178
>       el0t_64_sync+0x1a8/0x1b0
>
> Find a block with specific type to fix this.
> prmt find a block with EFI_RUNTIME_SERVICES_DATA for prm handler.
> prmt find a block with EFI_RUNTIME_SERVICES_CODE for prm context.
> By using the correct memory types for runtime services,
> we can ensure that the PRM handler and
> its context are properly mapped in the virtual address space during
> runtime,
> preventing the paging request error.

some general rules to follow when writing a changelog
https://docs.kernel.org/process/maintainer-tip.html 4.2.3. Changelog

>
> [1]
> https://uefi.org/sites/default/files/resources/UEFI_Spec_2_10_Aug29.pdf
>
> Fixes: cefc7ca46235 ("ACPI: PRM: implement OperationRegion handler
> for the PlatformRtMechanism subtype")
> Signed-off-by: KobaK <kobak@nvidia.com>
> Reviewed-by: Matthew R. Ochs <mochs@nvidia.com>
> ---
>  drivers/acpi/prmt.c | 46 ++++++++++++++++++++++++++++++-------------
> --
>  1 file changed, 31 insertions(+), 15 deletions(-)
>
> diff --git a/drivers/acpi/prmt.c b/drivers/acpi/prmt.c
> index c78453c74ef5..e2f0bdd81013 100644
> --- a/drivers/acpi/prmt.c
> +++ b/drivers/acpi/prmt.c
> @@ -72,17 +72,21 @@ struct prm_module_info {
>         struct prm_handler_info handlers[]
> __counted_by(handler_count);
>  };
>
> -static u64 efi_pa_va_lookup(u64 pa)
> +static u64 efi_pa_va_lookup(u64 pa, u32 type)
>  {
>         efi_memory_desc_t *md;
>         u64 pa_offset = pa & ~PAGE_MASK;
>         u64 page = pa & PAGE_MASK;
>
>         for_each_efi_memory_desc(md) {
> -               if (md->phys_addr < pa && pa < md->phys_addr +
> PAGE_SIZE * md->num_pages)
> +               if ((md->type == type) &&
> +                       (md->phys_addr < pa && pa < md->phys_addr +
> PAGE_SIZE * md->num_pages)) {
>                         return pa_offset + md->virt_addr + page - md-
> >phys_addr;
> +               }
>         }
>
> +       pr_err("PRM: Failed to find a block for pa: %lx type %u\n",
> pa, type);
> +

If it is a pr_err, why not error out?
or what is the proper handling for such failures?

>         return 0;
>  }
>
> @@ -148,9 +152,12 @@ acpi_parse_prmt(union acpi_subtable_headers
> *header, const unsigned long end)
>                 th = &tm->handlers[cur_handler];
>
>                 guid_copy(&th->guid, (guid_t *)handler_info-
> >handler_guid);
> -               th->handler_addr = (void
> *)efi_pa_va_lookup(handler_info->handler_address);
> -               th->static_data_buffer_addr =
> efi_pa_va_lookup(handler_info->static_data_buffer_address);
> -               th->acpi_param_buffer_addr =
> efi_pa_va_lookup(handler_info->acpi_param_buffer_address);
> +               th->handler_addr =
> +                       (void *)efi_pa_va_lookup(handler_info-
> >handler_address, EFI_RUNTIME_SERVICES_CODE);
> +               th->static_data_buffer_addr =
> +                       efi_pa_va_lookup(handler_info-
> >static_data_buffer_address, EFI_RUNTIME_SERVICES_DATA);
> +               th->acpi_param_buffer_addr =
> +                       efi_pa_va_lookup(handler_info-
> >acpi_param_buffer_address, EFI_RUNTIME_SERVICES_DATA);
>         } while (++cur_handler < tm->handler_count && (handler_info =
> get_next_handler(handler_info)));
>
>         return 0;
> @@ -250,8 +257,16 @@ static acpi_status
> acpi_platformrt_space_handler(u32 function,
>
>                 handler = find_prm_handler(&buffer->handler_guid);
>                 module = find_prm_module(&buffer->handler_guid);
> -               if (!handler || !module)
> -                       goto invalid_guid;
> +               if (!handler || !module) {
> +                       buffer->prm_status =
> PRM_HANDLER_GUID_NOT_FOUND;
> +                       goto error;

I think it is okay to return AE_OK directly, right?

thanks,
rui
> +               }
> +
> +               if (!handler->handler_addr || !handler-
> >static_data_buffer_addr ||
> +                       !handler->acpi_param_buffer_addr) {
> +                       buffer->prm_status = PRM_HANDLER_ERROR;
> +                       goto error;
> +               }
>
>                 ACPI_COPY_NAMESEG(context.signature, "PRMC");
>                 context.revision = 0x0;
> @@ -274,8 +289,10 @@ static acpi_status
> acpi_platformrt_space_handler(u32 function,
>         case PRM_CMD_START_TRANSACTION:
>
>                 module = find_prm_module(&buffer->handler_guid);
> -               if (!module)
> -                       goto invalid_guid;
> +               if (!module) {
> +                       buffer->prm_status =
> PRM_HANDLER_GUID_NOT_FOUND;
> +                       goto error;
> +               }
>
>                 if (module->updatable)
>                         module->updatable = false;
> @@ -286,8 +303,10 @@ static acpi_status
> acpi_platformrt_space_handler(u32 function,
>         case PRM_CMD_END_TRANSACTION:
>
>                 module = find_prm_module(&buffer->handler_guid);
> -               if (!module)
> -                       goto invalid_guid;
> +               if (!module) {
> +                       buffer->prm_status =
> PRM_HANDLER_GUID_NOT_FOUND;
> +                       goto error;
> +               }
>
>                 if (module->updatable)
>                         buffer->prm_status =
> UPDATE_UNLOCK_WITHOUT_LOCK;
> @@ -301,10 +320,7 @@ static acpi_status
> acpi_platformrt_space_handler(u32 function,
>                 break;
>         }
>
> -       return AE_OK;
> -
> -invalid_guid:
> -       buffer->prm_status = PRM_HANDLER_GUID_NOT_FOUND;
> +error:
>         return AE_OK;
>  }
>