Watchpoints

Watchpoints#

AMD DBG API: Watchpoints
Data Structures | Macros | Enumerations | Functions
Watchpoints

Operations related to AMD GPU hardware data watchpoints. More...

Data Structures

struct  amd_dbgapi_watchpoint_id_t
 Opaque hardware data watchpoint handle. More...
 
struct  amd_dbgapi_watchpoint_list_t
 A set of watchpoints. More...
 

Macros

#define AMD_DBGAPI_WATCHPOINT_NONE    AMD_DBGAPI_HANDLE_LITERAL (amd_dbgapi_watchpoint_id_t, 0)
 The NULL hardware data watchpoint handle. More...
 

Enumerations

enum  amd_dbgapi_watchpoint_info_t { AMD_DBGAPI_WATCHPOINT_INFO_PROCESS = 1 , AMD_DBGAPI_WATCHPOINT_INFO_ADDRESS = 2 , AMD_DBGAPI_WATCHPOINT_INFO_SIZE = 3 }
 Watchpoint queries that are supported by amd_dbgapi_watchpoint_get_info. More...
 
enum  amd_dbgapi_watchpoint_share_kind_t { AMD_DBGAPI_WATCHPOINT_SHARE_KIND_UNSUPPORTED = 0 , AMD_DBGAPI_WATCHPOINT_SHARE_KIND_UNSHARED = 1 , AMD_DBGAPI_WATCHPOINT_SHARE_KIND_SHARED = 2 }
 The way watchpoints are shared between processes. More...
 
enum  amd_dbgapi_watchpoint_kind_t { AMD_DBGAPI_WATCHPOINT_KIND_LOAD = 1 , AMD_DBGAPI_WATCHPOINT_KIND_STORE_AND_RMW = 2 , AMD_DBGAPI_WATCHPOINT_KIND_RMW = 3 , AMD_DBGAPI_WATCHPOINT_KIND_ALL = 4 }
 Watchpoint memory access kinds. More...
 

Functions

amd_dbgapi_status_t AMD_DBGAPI amd_dbgapi_watchpoint_get_info (amd_dbgapi_watchpoint_id_t watchpoint_id, amd_dbgapi_watchpoint_info_t query, size_t value_size, void *value) AMD_DBGAPI_VERSION_0_54
 Query information about a watchpoint. More...
 
amd_dbgapi_status_t AMD_DBGAPI amd_dbgapi_set_watchpoint (amd_dbgapi_process_id_t process_id, amd_dbgapi_global_address_t address, amd_dbgapi_size_t size, amd_dbgapi_watchpoint_kind_t kind, amd_dbgapi_watchpoint_id_t *watchpoint_id) AMD_DBGAPI_VERSION_0_62
 Set a hardware data watchpoint. More...
 
amd_dbgapi_status_t AMD_DBGAPI amd_dbgapi_remove_watchpoint (amd_dbgapi_process_id_t process_id, amd_dbgapi_watchpoint_id_t watchpoint_id) AMD_DBGAPI_VERSION_0_54
 Remove a hardware data watchpoint previously set by amd_dbgapi_set_watchpoint. More...
 

Detailed Description

Operations related to AMD GPU hardware data watchpoints.

A data watchpoint is a hardware supported mechanism to generate wave stop events after a wave accesses memory in a certain way in a certain address range. The memory access will have been completed before the event is reported.

The number of watchpoints, the granularity of base address, and the address range is process specific. If a process has multiple agents, then the values are the lowest common denominator of the capabilities of the architectures of all the agents of a process.

The number of watchpoints supported by a process is available using the AMD_DBGAPI_PROCESS_INFO_WATCHPOINT_COUNT query and may be 0. The AMD_DBGAPI_PROCESS_INFO_WATCHPOINT_SHARE query can be used to determine if watchpoints are shared between processes.

When a wave stops due to a data watchpoint the stop reason will include AMD_DBGAPI_WAVE_STOP_REASON_WATCHPOINT. The set of watchpoints triggered can be queried using AMD_DBGAPI_WAVE_INFO_WATCHPOINTS.

Macro Definition Documentation

◆ AMD_DBGAPI_WATCHPOINT_NONE

#define AMD_DBGAPI_WATCHPOINT_NONE    AMD_DBGAPI_HANDLE_LITERAL (amd_dbgapi_watchpoint_id_t, 0)

The NULL hardware data watchpoint handle.

Enumeration Type Documentation

◆ amd_dbgapi_watchpoint_info_t

enum amd_dbgapi_watchpoint_info_t

Watchpoint queries that are supported by amd_dbgapi_watchpoint_get_info.

Each query specifies the type of data returned in the value argument to amd_dbgapi_watchpoint_get_info.

Enumerator
AMD_DBGAPI_WATCHPOINT_INFO_PROCESS 

Return the process to which this watchpoint belongs.

The type of this attribute is amd_dbgapi_process_id_t.

AMD_DBGAPI_WATCHPOINT_INFO_ADDRESS 

The base address of the created watchpoint.

The type of this attribute is amd_dbgapi_global_address_t.

AMD_DBGAPI_WATCHPOINT_INFO_SIZE 

The byte size of the created watchpoint.

The type of this attribute is amd_dbgapi_size_t.

◆ amd_dbgapi_watchpoint_kind_t

enum amd_dbgapi_watchpoint_kind_t

Watchpoint memory access kinds.

The watchpoint is triggered only when the memory instruction is of the specified kind.

Enumerator
AMD_DBGAPI_WATCHPOINT_KIND_LOAD 

Read access by load instructions.

AMD_DBGAPI_WATCHPOINT_KIND_STORE_AND_RMW 

Write access by store instructions or read-modify-write access by atomic instructions.

AMD_DBGAPI_WATCHPOINT_KIND_RMW 

Read-modify-write access by atomic instructions.

AMD_DBGAPI_WATCHPOINT_KIND_ALL 

Read, write, or read-modify-write access by load, store, or atomic instructions.

◆ amd_dbgapi_watchpoint_share_kind_t

enum amd_dbgapi_watchpoint_share_kind_t

The way watchpoints are shared between processes.

The AMD_DBGAPI_PROCESS_INFO_WATCHPOINT_SHARE query can be used to determine the watchpoint sharing for an architecture.

Enumerator
AMD_DBGAPI_WATCHPOINT_SHARE_KIND_UNSUPPORTED 

Watchpoints are not supported.

AMD_DBGAPI_WATCHPOINT_SHARE_KIND_UNSHARED 

The watchpoints are not shared across processes.

Every process can use all AMD_DBGAPI_PROCESS_INFO_WATCHPOINT_COUNT watchpoints.

AMD_DBGAPI_WATCHPOINT_SHARE_KIND_SHARED 

The watchpoints of a process are shared between all processes.

The number of watchpoints available to a process may be reduced if watchpoints are used by another process.

Function Documentation

◆ amd_dbgapi_remove_watchpoint()

amd_dbgapi_status_t AMD_DBGAPI amd_dbgapi_remove_watchpoint ( amd_dbgapi_process_id_t  process_id,
amd_dbgapi_watchpoint_id_t  watchpoint_id 
)

Remove a hardware data watchpoint previously set by amd_dbgapi_set_watchpoint.

Parameters
[in]process_idThe process that owns the watchpoint.
[in]watchpoint_idThe watchpoint to remove.
Return values
AMD_DBGAPI_STATUS_SUCCESSThe function has been executed successfully and the watchpoint has been removed.
AMD_DBGAPI_STATUS_FATALA fatal error occurred. The library is left uninitialized.
AMD_DBGAPI_STATUS_ERROR_NOT_INITIALIZEDThe library is not initialized. The library is left uninitialized and no watchpoint is removed.
AMD_DBGAPI_STATUS_ERROR_INVALID_PROCESS_IDprocess_id is invalid. No watchpoint is removed.
AMD_DBGAPI_STATUS_ERROR_INVALID_WATCHPOINT_IDwatchpoint_id is invalid. No watchpoint is removed.

◆ amd_dbgapi_set_watchpoint()

amd_dbgapi_status_t AMD_DBGAPI amd_dbgapi_set_watchpoint ( amd_dbgapi_process_id_t  process_id,
amd_dbgapi_global_address_t  address,
amd_dbgapi_size_t  size,
amd_dbgapi_watchpoint_kind_t  kind,
amd_dbgapi_watchpoint_id_t *  watchpoint_id 
)

Set a hardware data watchpoint.

The AMD GPU has limitations on the base address and size of hardware data watchpoints that can be set, and the limitations may vary by architecture. A watchpoint is created with the smallest range, supported by the architectures of all the agents of a process, that covers the requested range specified by address and size.

If the requested range is larger than is supported by the architectures of all the agents of a process, then a watchpoint is created with the smallest range that includes address and covers as much of the requested range as possible.

The range of the created watchpoint can be queried using AMD_DBGAPI_WATCHPOINT_INFO_PROCESS and AMD_DBGAPI_WATCHPOINT_INFO_SIZE. The client is responsible for determining if the created watchpoint completely covers the requested range. If it does not, the client can attempt to create additional watchpoints for the uncovered portion of the requested range.

When a watchpoint is triggered, the client is responsible for determining if the access was to the requested range. For example, for writes the client can compare the original value with the current value to determine if it changed.

Each process has its own set of watchpoints. Only waves executing on the agents of a process will trigger the watchpoints set on that process.

Parameters
[in]process_idThe process on which to set the watchpoint.
[in]addressThe base address of memory area to set a watchpoint.
[in]sizeThe non-zero number of bytes that the watchpoint should cover.
[in]kindThe kind of memory access that should trigger the watchpoint.
[out]watchpoint_idThe watchpoint created.
Return values
AMD_DBGAPI_STATUS_SUCCESSThe function has been executed successfully and the watchpoint has been created with handle watchpoint_id.
AMD_DBGAPI_STATUS_FATALA fatal error occurred. The library is left uninitialized; and watchpoint_id is unaltered.
AMD_DBGAPI_STATUS_ERROR_NOT_INITIALIZEDThe library is not initialized. The library is left uninitialized; and watchpoint_id is unaltered.
AMD_DBGAPI_STATUS_ERROR_INVALID_PROCESS_IDprocess_id is invalid. No watchpoint is set and watchpoint_id is unaltered.
AMD_DBGAPI_STATUS_ERROR_NO_WATCHPOINT_AVAILABLENo more watchpoints are available. No watchpoint is set and watchpoint_id is unaltered.
AMD_DBGAPI_STATUS_ERROR_NOT_SUPPORTEDWatchpoints are not supported for the architectures of all the agents. No watchpoint is set and watchpoint_id is unaltered.
AMD_DBGAPI_STATUS_ERROR_INVALID_ARGUMENTkind is invalid; size is 0 or watchpoint_id is NULL. No watchpoint is set and watchpoint_id is unaltered.

◆ amd_dbgapi_watchpoint_get_info()

amd_dbgapi_status_t AMD_DBGAPI amd_dbgapi_watchpoint_get_info ( amd_dbgapi_watchpoint_id_t  watchpoint_id,
amd_dbgapi_watchpoint_info_t  query,
size_t  value_size,
void *  value 
)

Query information about a watchpoint.

amd_dbgapi_watchpoint_info_t specifies the queries supported and the type returned using the value argument.

Parameters
[in]watchpoint_idThe handle of the watchpoint being queried.
[in]queryThe query being requested.
[in]value_sizeSize of the memory pointed to by value. Must be equal to the byte size of the query result.
[out]valuePointer to memory where the query result is stored.
Return values
AMD_DBGAPI_STATUS_SUCCESSThe function has been executed successfully and the result is stored in value.
AMD_DBGAPI_STATUS_FATALA fatal error occurred. The library is left uninitialized and value is unaltered.
AMD_DBGAPI_STATUS_ERROR_NOT_INITIALIZEDThe library is not initialized. The library is left uninitialized and value is unaltered.
AMD_DBGAPI_STATUS_ERROR_INVALID_WATCHPOINT_IDwatchpoint_id is invalid. value is unaltered.
AMD_DBGAPI_STATUS_ERROR_INVALID_ARGUMENTvalue is NULL or query is invalid. value is unaltered.
AMD_DBGAPI_STATUS_ERROR_INVALID_ARGUMENT_COMPATIBILITYvalue_size does not match the size of the query result. value is unaltered.
AMD_DBGAPI_STATUS_ERROR_CLIENT_CALLBACKThis will be reported if the amd_dbgapi_callbacks_s::allocate_memory callback used to allocate value returns NULL. value is unaltered.