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

Zhang, Rui
2024-08-21T04:55:35Z

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.

> > >          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;
> > >   }
> > >
>