diff options
Diffstat (limited to 'src/usr/trace/runtime/rt_rsvdtracebuffer.H')
| -rw-r--r-- | src/usr/trace/runtime/rt_rsvdtracebuffer.H | 79 |
1 files changed, 59 insertions, 20 deletions
diff --git a/src/usr/trace/runtime/rt_rsvdtracebuffer.H b/src/usr/trace/runtime/rt_rsvdtracebuffer.H index 24c9204cf..e804a41ed 100644 --- a/src/usr/trace/runtime/rt_rsvdtracebuffer.H +++ b/src/usr/trace/runtime/rt_rsvdtracebuffer.H @@ -5,7 +5,7 @@ /* */ /* OpenPOWER HostBoot Project */ /* */ -/* Contributors Listed Below - COPYRIGHT 2012,2018 */ +/* Contributors Listed Below - COPYRIGHT 2012,2019 */ /* [+] International Business Machines Corp. */ /* */ /* */ @@ -43,9 +43,25 @@ namespace TRACE * * @brief Class to manage the Reserved Trace Buffer * - * This is a utility class to manage the buffer - looking for space - * for an entry, adding entries and removing entries. - * + * @details This is a utility class to manage the buffer - looking + * for space for an entry, adding entries and removing entries. + * When a system crashes, this buffer will persist the last + * few traces. When HB is IPLed again, the persisted data + * will be retrieved for inspection. + * With PHYP, the buffer will be retrieved at the same memory + * location as before the crash. With OPAL, the buffer may be + * relocated to a different location and all the pointers within + * the buffer will be invalid. If the buffer does get relocated, + * this class will correct the pointers. + * To correct the pointers, a section at the beginning of the + * persisted buffer is reserved to save the address of the buffer. + * Such that when the buffer is retrieved after a crash, if that + * data does not match the current buffer address, then we can + * conclude it has been relocated and the pointers in the buffer + * need to be updated/corrected. + * If the data at the beginning of the buffer is 0, then this is + * first time this buffer is being used and therefore no need to + * correct pointers. */ class RsvdTraceBuffer { @@ -61,7 +77,7 @@ namespace TRACE * * @param[in] i_addressToBuffer - Where the buffer begins * - * @param[in] i_addressToHead - A pointer to a ponter to the first + * @param[in] i_addressToHead - A pointer to a pointer to the first * Entry, cannot be a nullptr */ void init(uint32_t i_bufferSize, @@ -89,12 +105,12 @@ namespace TRACE * If o_data is valid and the i_size is greater than * the size of trace_buf_head_t, then as many trace * entries will be returned in the o_data buffer that - * i_size will allow. + * i_size will allow, minus size of trace_buf_head_t. * - * @param[in] o_data - if not null, the buffer area to copy + * @param[out] o_data - if not null, the buffer area to copy * trace data into * - * @param[out] i_dataSize - if not 0, the size of the buffer area, + * @param[in] i_dataSize - if not 0, the size of the buffer area, * which dictates how many trace entries' * payload (or data the entry contains) * that can be copied @@ -123,7 +139,23 @@ namespace TRACE */ uint32_t getNumberOfEntries() const; + // Private methods private: + + /** @brief Checks the buffer to see if it has been relocated and if + * so, realign the pointers within the buffer. + */ + void checkBuffer(); + + + /** @brief When and if buffer has been relocated this method will + * realign the pointers within the buffer. + * + * @param[in] i_offset - the offset the buffer has moved + * within memory + */ + void realignListPointers(intptr_t i_offset); + /** @brief This function will find a contiguous piece of memory that * is large enough in size to accommodate the space needed. * If not enough free contiguous memory exists to accommodate @@ -147,7 +179,8 @@ namespace TRACE * requested is not larger in size to the buffer size, * then an available space will eventually be returned. * - * @param[in] i_spaceNeeded - @see insertEntry::i_dataSize above + * @param[in] i_spaceNeeded - The size of the contiguous piece + * of memory caller desires * * @param[out] o_availableAddress - A pointer to the contiguous * piece of memory found that satisfies the caller's @@ -160,8 +193,8 @@ namespace TRACE char* &o_availableAddress); /** @brief Returns a contiguous piece of memory that will satisfy - * the space that is needed if large enough space can be - * had, else returns the size of the largest contiguous + * the space that is needed if a large enough space can be + * found, else return the size of the largest contiguous * piece of memory. * * @algorithm There are three cases to consider: @@ -176,7 +209,7 @@ namespace TRACE * --------------------------------------------------------- * | < - 10 bytes -> | Head | .....| Tail | <- 20 bytes -> | * --------------------------------------------------------- - * scenario 1: Contigous space desired: 15 bytes + * scenario 1: Contiguous space desired: 15 bytes * Return the 20 bytes after the Tail * scenario 2: Contiguous space desired: 10 bytes * Return the 20 bytes after the Tail @@ -223,18 +256,21 @@ namespace TRACE * --------------------------------------------------------- * | .... | Tail | < - 30 bytes -> | Head | .... * --------------------------------------------------------- - * Case 1: Contigous space desired: 25 bytes + * Case 1: Contiguous space desired: 25 bytes * Return the 30 bytes between Tail and Head. - * Case 2: Contigous space desired: 40 bytes + * Case 2: Contiguous space desired: 40 bytes * Return the 30 bytes between Tail and Head. * - * @param[in] i_spaceNeeded - @see insertEntry::i_dataSize above + * @param[in] i_spaceNeeded - The size of the contiguous piece + * of memory caller desires * - * @param[out] o_availableAddress - @see makeSpaceForEntry above + * @param[out] o_availableAddress - A pointer to the biggest + * piece of contiguous memory found. May or may + * not satisfy i_spaceNeeded. * * @return The minimum size of the space found that meets the * requested space needed; or the largest size that comes - * close to meeting the space needed + * close to meeting the space needed. * */ uint32_t getAvailableSpace(uint32_t i_spaceNeeded, @@ -256,7 +292,7 @@ namespace TRACE uint32_t getAggregateSizeOfEntries() const; /** @brief This will return as many data entries that can be - * accommodated by size + * accommodated by i_dataSize * * @param[out] o_data - the buffer area to copy trace data into * @@ -380,7 +416,6 @@ namespace TRACE * * @param[in] i_tail - a pointer to an Entry data type; * OK to be a nullptr - * */ void setListTail(Entry* i_newEntry) { @@ -448,9 +483,13 @@ namespace TRACE void clearPtrToHead() { iv_ptrToHead = nullptr; } + // Private data members + private: + uintptr_t* iv_ptrToRsvdMem; //< Pointer to Reserved Memory. Used to + // realign pointers if RsvdMem relocates + uintptr_t* iv_ptrToHead; //< Pointer to oldest Entry (time wise) char *iv_bufferBeginningBoundary; //< Pointer to beginning of buffer char *iv_bufferEndingBoundary; //< Pointer to end of buffer - uintptr_t* iv_ptrToHead; //< Pointer to oldest Entry (time wise) bool iv_isBufferValid; //< Indicates an initialized buffer // For testing purposes only |
