Re: [PATCH V5] acpi/prmt: find block with specific type

[Rafael J. Wysocki]

On Wed, Sep 11, 2024 at 5:55 PM KobaK <kobak@xxxxxxxxxx> 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.
>
>     [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 and
> find a block with EFI_RUNTIME_SERVICES_CODE for prm context.
> If no suitable block is found, a warning message will be prompted
> but the procedue continues to manage the next prm handler.
> However, if the prm handler is actullay called without proper allocation,
> it would result in a failure during error handling.
>
> By using the correct memory types for runtime services,
> Ensure that the PRM handler and the context are
> properly mapped in the virtual address space during runtime,
> preventing the paging request error.
>
> [1] https://uefi.org/sites/default/files/resources/UEFI_Spec_2_10_Aug29.pdf

I need input from EFI people on this, so can you please resend the
patch with a CC to linux-efi@xxxxxxxxxxxxxxx?

> Fixes: cefc7ca46235 ("ACPI: PRM: implement OperationRegion handler for the PlatformRtMechanism subtype")
> Signed-off-by: KobaK <kobak@xxxxxxxxxx>
> Reviewed-by: Matthew R. Ochs <mochs@xxxxxxxxxx>
> ---
> V2:
> 1. format the changelog and add more about error handling.
> 2. replace goto
> V3: Warn if parts of handler are missed during va-pa translating.
> V4: Fix the 0day
> V5: Fix typo and pr_warn warning
> ---
>  drivers/acpi/prmt.c | 49 +++++++++++++++++++++++++++++++--------------
>  1 file changed, 34 insertions(+), 15 deletions(-)
>
> diff --git a/drivers/acpi/prmt.c b/drivers/acpi/prmt.c
> index c78453c74ef5..cd4a7f5491d6 100644
> --- a/drivers/acpi/prmt.c
> +++ b/drivers/acpi/prmt.c
> @@ -72,15 +72,17 @@ 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;
> +               }
>         }
>
>         return 0;
> @@ -148,9 +150,18 @@ 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);
> +
> +               if (!th->handler_addr || !th->static_data_buffer_addr || !th->acpi_param_buffer_addr)
> +                       pr_warn(
> +                               "Idx: %llu, Parts of handler(GUID: %pUL) are missed, handler_addr %p, data_addr %p, param_addr %p",
> +                               cur_handler, &th->guid, th->handler_addr,
> +                               (void *)th->static_data_buffer_addr, (void *)th->acpi_param_buffer_addr);
>         } while (++cur_handler < tm->handler_count && (handler_info = get_next_handler(handler_info)));
>
>         return 0;
> @@ -250,8 +261,16 @@ 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;
> +                       return AE_OK;
> +               }
> +
> +               if (!handler->handler_addr || !handler->static_data_buffer_addr ||
> +                       !handler->acpi_param_buffer_addr) {
> +                       buffer->prm_status = PRM_HANDLER_ERROR;
> +                       return AE_OK;
> +               }
>
>                 ACPI_COPY_NAMESEG(context.signature, "PRMC");
>                 context.revision = 0x0;
> @@ -274,8 +293,10 @@ 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;
> +                       return AE_OK;
> +               }
>
>                 if (module->updatable)
>                         module->updatable = false;
> @@ -286,8 +307,10 @@ 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;
> +                       return AE_OK;
> +               }
>
>                 if (module->updatable)
>                         buffer->prm_status = UPDATE_UNLOCK_WITHOUT_LOCK;
> @@ -302,10 +325,6 @@ static acpi_status acpi_platformrt_space_handler(u32 function,
>         }
>
>         return AE_OK;
> -
> -invalid_guid:
> -       buffer->prm_status = PRM_HANDLER_GUID_NOT_FOUND;
> -       return AE_OK;
>  }
>
>  void __init init_prmt(void)
> --
> 2.43.0
>
>