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

Koba Ko
2024-08-21T05:48:07Z

On 8/21/24 12:55, Zhang, Rui wrote:
> External email: Use caution opening links or attachments
>
>
> On Wed, 2024-08-21 at 12:01 +0800, Koba Ko wrote:
>> On 8/21/24 11:20, Zhang, Rui wrote:
>>> External email: Use caution opening links or attachments
>>>
>>>
>>> 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
>> will fix this in the description.
>>>
>>>> [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
>> will decorate this.
>>>> [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?
>>>
> Not sure if you missed this one.
> It is not clear what is the expected behavior in this case. Better to
> describe this in the changelog as well.

Sorry, missed.
if get failure and return 0.
in acpi_platformrt_space_handler, it takes care to handle the null pointers.
```
+               if (!handler->handler_addr ||
!handler->static_data_buffer_addr ||
+                       !handler->acpi_param_buffer_addr) {
+                       buffer->prm_status = PRM_HANDLER_ERROR;
+                       goto error;
+               }
```
will also update in the description.

>>>> 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
>> I'm also good for this.
>> I followed the convention in this block.
>> If change to "return", i will change all "goto error".
>> How do you think?
> sounds good to me.
>
> -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;
>>>> }
>>>>