From: Anshuman Khandual anshuman.khandual@arm.com
mainline inclusion from mainline-v6.1-rc1 commit b190bc4ac9e6d9763b61654c5a0c085ff77d7a09 category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/I8EC9K CVE: NA
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
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branch_entry.type now has ran out of space to accommodate more branch types classification. This will prevent perf branch stack implementation on arm64 (via BRBE) to capture all available branch types. Extending this bit field i.e branch_entry.type [4 bits] is not an option as it will break user space ABI both for little and big endian perf tools.
Extend branch classification with a new field branch_entry.new_type via a new branch type PERF_BR_EXTEND_ABI in branch_entry.type. Perf tools which could decode PERF_BR_EXTEND_ABI, will then parse branch_entry.new_type as well.
branch_entry.new_type is a 4 bit field which can hold upto 16 branch types. The first three branch types will hold various generic page faults followed by five architecture specific branch types, which can be overridden by the platform for specific use cases. These architecture specific branch types gets overridden on arm64 platform for BRBE implementation.
New generic branch types
- PERF_BR_NEW_FAULT_ALGN - PERF_BR_NEW_FAULT_DATA - PERF_BR_NEW_FAULT_INST
New arch specific branch types
- PERF_BR_NEW_ARCH_1 - PERF_BR_NEW_ARCH_2 - PERF_BR_NEW_ARCH_3 - PERF_BR_NEW_ARCH_4 - PERF_BR_NEW_ARCH_5
Signed-off-by: Anshuman Khandual anshuman.khandual@arm.com Signed-off-by: Peter Zijlstra (Intel) peterz@infradead.org Reviewed-by: James Clark james.clark@arm.com Link: https://lkml.kernel.org/r/20220824044822.70230-3-anshuman.khandual@arm.com Signed-off-by: Junhao He hejunhao3@huawei.com --- include/uapi/linux/perf_event.h | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-)
diff --git a/include/uapi/linux/perf_event.h b/include/uapi/linux/perf_event.h index 9ce89da2a863..e42c39ae1f14 100644 --- a/include/uapi/linux/perf_event.h +++ b/include/uapi/linux/perf_event.h @@ -239,6 +239,7 @@ enum { PERF_BR_IRQ = 12, /* irq */ PERF_BR_SERROR = 13, /* system error */ PERF_BR_NO_TX = 14, /* not in transaction */ + PERF_BR_EXTEND_ABI = 15, /* extend ABI */ PERF_BR_MAX, };
@@ -253,6 +254,18 @@ enum { PERF_BR_SPEC_MAX, };
+enum { + PERF_BR_NEW_FAULT_ALGN = 0, /* Alignment fault */ + PERF_BR_NEW_FAULT_DATA = 1, /* Data fault */ + PERF_BR_NEW_FAULT_INST = 2, /* Inst fault */ + PERF_BR_NEW_ARCH_1 = 3, /* Architecture specific */ + PERF_BR_NEW_ARCH_2 = 4, /* Architecture specific */ + PERF_BR_NEW_ARCH_3 = 5, /* Architecture specific */ + PERF_BR_NEW_ARCH_4 = 6, /* Architecture specific */ + PERF_BR_NEW_ARCH_5 = 7, /* Architecture specific */ + PERF_BR_NEW_MAX, +}; + #define PERF_SAMPLE_BRANCH_PLM_ALL \ (PERF_SAMPLE_BRANCH_USER|\ PERF_SAMPLE_BRANCH_KERNEL|\ @@ -1312,7 +1325,8 @@ struct perf_branch_entry { cycles:16, /* cycle count to last branch */ type:4, /* branch type */ spec:2, /* branch speculation info */ - reserved:38; + new_type:4, /* additional branch type */ + reserved:34; };
union perf_sample_weight {