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

["Zhang, Rui" <rui.zhang@intel.com>]

On Wed, 2024-08-21 at 13:48 +0800, Koba Ko wrote:
> 
> 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.

Yeah, but I mean pr_err() may be overkill if the driver is still
functional.

thanks,
rui

> 
> > > > >           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;
> > > > >    }
> > > > >