Re: [PATCH 04/11] ACPICA: Events: Fix acpi_ev_initialize_region() return value

From: Rafael J. Wysocki
Date: Wed Nov 30 2016 - 18:08:06 EST

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In reply to: Lv Zheng: "[PATCH 04/11] ACPICA: Events: Fix acpi_ev_initialize_region() return value"
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On Wed, Nov 30, 2016 at 8:21 AM, Lv Zheng <lv.zheng@xxxxxxxxx> wrote:
> ACPICA commit 543342ab7a676f4eb0c9f100d349388a84dff0e8
>
> This patch changes acpi_ev_initialize_region(), stop returning AE_NOT_EXIST
> from it so that, not only in acpi_ds_load2_end_op(), but all places invoking
> this function won't emit exceptions. The exception can be seen in
> acpi_ds_initialize_objects() when certain table loading mode is chosen.
>
> This patch also removes useless acpi_ns_locked from acpi_ev_initialize_region()
> as this function will always be invoked with interpreter lock held now, and
> the lock granularity has been tuned to lock around _REG execution, thus it
> is now handled by acpi_ex_exit_interpreter(). Lv Zheng.
>
> Link: https://github.com/acpica/acpica/commit/543342ab
> Signed-off-by: Lv Zheng <lv.zheng@xxxxxxxxx>
> Signed-off-by: Bob Moore <robert.moore@xxxxxxxxx>
> ---
> drivers/acpi/acpica/acevents.h | 4 +--
> drivers/acpi/acpica/dsopcode.c | 2 +-
> drivers/acpi/acpica/dswload2.c | 13 +--------
> drivers/acpi/acpica/evrgnini.c | 59 ++++++++++++++++------------------------
> 4 files changed, 27 insertions(+), 51 deletions(-)
>
> diff --git a/drivers/acpi/acpica/acevents.h b/drivers/acpi/acpica/acevents.h
> index 92fa47c..8a0049d 100644
> --- a/drivers/acpi/acpica/acevents.h
> +++ b/drivers/acpi/acpica/acevents.h
> @@ -243,9 +243,7 @@ union acpi_operand_object *acpi_ev_find_region_handler(acpi_adr_space_type
> u32 function,
> void *handler_context, void **region_context);
>
> -acpi_status
> -acpi_ev_initialize_region(union acpi_operand_object *region_obj,
> - u8 acpi_ns_locked);
> +acpi_status acpi_ev_initialize_region(union acpi_operand_object *region_obj);
>
> /*
> * evsci - SCI (System Control Interrupt) handling/dispatch
> diff --git a/drivers/acpi/acpica/dsopcode.c b/drivers/acpi/acpica/dsopcode.c
> index 4cc9d98..77fd7c8 100644
> --- a/drivers/acpi/acpica/dsopcode.c
> +++ b/drivers/acpi/acpica/dsopcode.c
> @@ -84,7 +84,7 @@ acpi_status acpi_ds_initialize_region(acpi_handle obj_handle)
>
> /* Namespace is NOT locked */
>
> - status = acpi_ev_initialize_region(obj_desc, FALSE);
> + status = acpi_ev_initialize_region(obj_desc);
> return (status);
> }
>
> diff --git a/drivers/acpi/acpica/dswload2.c b/drivers/acpi/acpica/dswload2.c
> index e362182..651f35a 100644
> --- a/drivers/acpi/acpica/dswload2.c
> +++ b/drivers/acpi/acpica/dswload2.c
> @@ -609,18 +609,7 @@ acpi_status acpi_ds_load2_end_op(struct acpi_walk_state *walk_state)
>
> status =
> acpi_ev_initialize_region
> - (acpi_ns_get_attached_object(node), FALSE);
> -
> - if (ACPI_FAILURE(status)) {
> - /*
> - * If AE_NOT_EXIST is returned, it is not fatal
> - * because many regions get created before a handler
> - * is installed for said region.
> - */
> - if (AE_NOT_EXIST == status) {
> - status = AE_OK;
> - }
> - }
> + (acpi_ns_get_attached_object(node));

This hunk doesn't apply for me.

We have acpi_ex_exit_interpreter() / acpi_ex_enter_interpreter()
around the acpi_ev_initialize_region() in linux-next.

> break;
>
> case AML_NAME_OP:
> diff --git a/drivers/acpi/acpica/evrgnini.c b/drivers/acpi/acpica/evrgnini.c
> index 75ddd16..a909225 100644
> --- a/drivers/acpi/acpica/evrgnini.c
> +++ b/drivers/acpi/acpica/evrgnini.c
> @@ -479,7 +479,6 @@ static u8 acpi_ev_is_pci_root_bridge(struct acpi_namespace_node *node)
> * FUNCTION: acpi_ev_initialize_region
> *
> * PARAMETERS: region_obj - Region we are initializing
> - * acpi_ns_locked - Is namespace locked?
> *
> * RETURN: Status
> *
> @@ -497,19 +496,28 @@ static u8 acpi_ev_is_pci_root_bridge(struct acpi_namespace_node *node)
> * MUTEX: Interpreter should be unlocked, because we may run the _REG
> * method for this region.
> *
> + * NOTE: Possible incompliance:
> + * There is a behavior conflict in automatic _REG execution:
> + * 1. When the interpreter is evaluating a method, we can only
> + * automatically run _REG for the following case:
> + * operation_region (OPR1, 0x80, 0x1000010, 0x4)
> + * 2. When the interpreter is loading a table, we can also
> + * automatically run _REG for the following case:
> + * operation_region (OPR1, 0x80, 0x1000010, 0x4)
> + * Though this may not be compliant to the de-facto standard, the
> + * logic is kept in order not to trigger regressions. And keeping
> + * this logic should be taken care by the caller of this function.
> + *
> ******************************************************************************/
>
> -acpi_status
> -acpi_ev_initialize_region(union acpi_operand_object *region_obj,
> - u8 acpi_ns_locked)
> +acpi_status acpi_ev_initialize_region(union acpi_operand_object *region_obj)
> {
> union acpi_operand_object *handler_obj;
> union acpi_operand_object *obj_desc;
> acpi_adr_space_type space_id;
> struct acpi_namespace_node *node;
> - acpi_status status;
>
> - ACPI_FUNCTION_TRACE_U32(ev_initialize_region, acpi_ns_locked);
> + ACPI_FUNCTION_TRACE(ev_initialize_region);
>
> if (!region_obj) {
> return_ACPI_STATUS(AE_BAD_PARAMETER);
> @@ -580,39 +588,17 @@ static u8 acpi_ev_is_pci_root_bridge(struct acpi_namespace_node *node)
> handler_obj, region_obj,
> obj_desc));
>
> - status =
> - acpi_ev_attach_region(handler_obj,
> - region_obj,
> - acpi_ns_locked);
> + (void)acpi_ev_attach_region(handler_obj,
> + region_obj, FALSE);
>
> /*
> * Tell all users that this region is usable by
> * running the _REG method
> */
> - if (acpi_ns_locked) {
> - status =
> - acpi_ut_release_mutex
> - (ACPI_MTX_NAMESPACE);
> - if (ACPI_FAILURE(status)) {
> - return_ACPI_STATUS(status);
> - }
> - }
> -
> acpi_ex_exit_interpreter();
> - status =
> - acpi_ev_execute_reg_method(region_obj,
> - ACPI_REG_CONNECT);
> + (void)acpi_ev_execute_reg_method(region_obj,
> + ACPI_REG_CONNECT);
> acpi_ex_enter_interpreter();

And this also doesn't apply, because we don't invoke
acpi_ex_exit_interpreter() / acpi_ex_enter_interpreter() around the
acpi_ev_execute_reg_method() call in linux-next.

> -
> - if (acpi_ns_locked) {
> - status =
> - acpi_ut_acquire_mutex
> - (ACPI_MTX_NAMESPACE);
> - if (ACPI_FAILURE(status)) {
> - return_ACPI_STATUS(status);
> - }
> - }
> -
> return_ACPI_STATUS(AE_OK);
> }
> }
> @@ -622,12 +608,15 @@ static u8 acpi_ev_is_pci_root_bridge(struct acpi_namespace_node *node)
> node = node->parent;
> }
>
> - /* If we get here, there is no handler for this region */
> -
> + /*
> + * If we get here, there is no handler for this region. This is not
> + * fatal because many regions get created before a handler is installed
> + * for said region.
> + */
> ACPI_DEBUG_PRINT((ACPI_DB_OPREGION,
> "No handler for RegionType %s(%X) (RegionObj %p)\n",
> acpi_ut_get_region_name(space_id), space_id,
> region_obj));
>
> - return_ACPI_STATUS(AE_NOT_EXIST);
> + return_ACPI_STATUS(AE_OK);
> }
> --

Thanks,
Rafael

Next message: Josh Poimboeuf: "[PATCH] x86/suspend: fix false positive KASAN warning on suspend/resume"
Previous message: Stephen Rothwell: "linux-next: build warning after merge of the kbuild tree"
In reply to: Lv Zheng: "[PATCH 04/11] ACPICA: Events: Fix acpi_ev_initialize_region() return value"
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