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authorLinus Torvalds <torvalds@linux-foundation.org>2022-10-06 21:51:49 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2022-10-06 21:51:49 +0300
commit18fd049731e67651009f316195da9281b756f2cf (patch)
tree082c87950f33bc466672ea3fd2ea24e5b2a37253 /Documentation/admin-guide
parent41fc64a0550b86f4428e8d3fa23ab97678a65ae8 (diff)
parentd2995249a2f72333a4ab4922ff3c42a76c023791 (diff)
downloadlinux-18fd049731e67651009f316195da9281b756f2cf.tar.xz
Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux
Pull arm64 updates from Catalin Marinas: - arm64 perf: DDR PMU driver for Alibaba's T-Head Yitian 710 SoC, SVE vector granule register added to the user regs together with SVE perf extensions documentation. - SVE updates: add HWCAP for SVE EBF16, update the SVE ABI documentation to match the actual kernel behaviour (zeroing the registers on syscall rather than "zeroed or preserved" previously). - More conversions to automatic system registers generation. - vDSO: use self-synchronising virtual counter access in gettimeofday() if the architecture supports it. - arm64 stacktrace cleanups and improvements. - arm64 atomics improvements: always inline assembly, remove LL/SC trampolines. - Improve the reporting of EL1 exceptions: rework BTI and FPAC exception handling, better EL1 undefs reporting. - Cortex-A510 erratum 2658417: remove BF16 support due to incorrect result. - arm64 defconfig updates: build CoreSight as a module, enable options necessary for docker, memory hotplug/hotremove, enable all PMUs provided by Arm. - arm64 ptrace() support for TPIDR2_EL0 (register provided with the SME extensions). - arm64 ftraces updates/fixes: fix module PLTs with mcount, remove unused function. - kselftest updates for arm64: simple HWCAP validation, FP stress test improvements, validation of ZA regs in signal handlers, include larger SVE and SME vector lengths in signal tests, various cleanups. - arm64 alternatives (code patching) improvements to robustness and consistency: replace cpucap static branches with equivalent alternatives, associate callback alternatives with a cpucap. - Miscellaneous updates: optimise kprobe performance of patching single-step slots, simplify uaccess_mask_ptr(), move MTE registers initialisation to C, support huge vmalloc() mappings, run softirqs on the per-CPU IRQ stack, compat (arm32) misalignment fixups for multiword accesses. * tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (126 commits) arm64: alternatives: Use vdso/bits.h instead of linux/bits.h arm64/kprobe: Optimize the performance of patching single-step slot arm64: defconfig: Add Coresight as module kselftest/arm64: Handle EINTR while reading data from children kselftest/arm64: Flag fp-stress as exiting when we begin finishing up kselftest/arm64: Don't repeat termination handler for fp-stress ARM64: reloc_test: add __init/__exit annotations to module init/exit funcs arm64/mm: fold check for KFENCE into can_set_direct_map() arm64: ftrace: fix module PLTs with mcount arm64: module: Remove unused plt_entry_is_initialized() arm64: module: Make plt_equals_entry() static arm64: fix the build with binutils 2.27 kselftest/arm64: Don't enable v8.5 for MTE selftest builds arm64: uaccess: simplify uaccess_mask_ptr() arm64: asm/perf_regs.h: Avoid C++-style comment in UAPI header kselftest/arm64: Fix typo in hwcap check arm64: mte: move register initialization to C arm64: mm: handle ARM64_KERNEL_USES_PMD_MAPS in vmemmap_populate() arm64: dma: Drop cache invalidation from arch_dma_prep_coherent() arm64/sve: Add Perf extensions documentation ...
Diffstat (limited to 'Documentation/admin-guide')
-rw-r--r--Documentation/admin-guide/kernel-parameters.txt7
-rw-r--r--Documentation/admin-guide/perf/alibaba_pmu.rst100
-rw-r--r--Documentation/admin-guide/perf/index.rst1
3 files changed, 107 insertions, 1 deletions
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index e92d63d3e878..faa9f4137679 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -3203,6 +3203,7 @@
spectre_v2_user=off [X86]
spec_store_bypass_disable=off [X86,PPC]
ssbd=force-off [ARM64]
+ nospectre_bhb [ARM64]
l1tf=off [X86]
mds=off [X86]
tsx_async_abort=off [X86]
@@ -3609,7 +3610,7 @@
nohugeiomap [KNL,X86,PPC,ARM64] Disable kernel huge I/O mappings.
- nohugevmalloc [PPC] Disable kernel huge vmalloc mappings.
+ nohugevmalloc [KNL,X86,PPC,ARM64] Disable kernel huge vmalloc mappings.
nosmt [KNL,S390] Disable symmetric multithreading (SMT).
Equivalent to smt=1.
@@ -3627,6 +3628,10 @@
vulnerability. System may allow data leaks with this
option.
+ nospectre_bhb [ARM64] Disable all mitigations for Spectre-BHB (branch
+ history injection) vulnerability. System may allow data leaks
+ with this option.
+
nospec_store_bypass_disable
[HW] Disable all mitigations for the Speculative Store Bypass vulnerability
diff --git a/Documentation/admin-guide/perf/alibaba_pmu.rst b/Documentation/admin-guide/perf/alibaba_pmu.rst
new file mode 100644
index 000000000000..11de998bb480
--- /dev/null
+++ b/Documentation/admin-guide/perf/alibaba_pmu.rst
@@ -0,0 +1,100 @@
+=============================================================
+Alibaba's T-Head SoC Uncore Performance Monitoring Unit (PMU)
+=============================================================
+
+The Yitian 710, custom-built by Alibaba Group's chip development business,
+T-Head, implements uncore PMU for performance and functional debugging to
+facilitate system maintenance.
+
+DDR Sub-System Driveway (DRW) PMU Driver
+=========================================
+
+Yitian 710 employs eight DDR5/4 channels, four on each die. Each DDR5 channel
+is independent of others to service system memory requests. And one DDR5
+channel is split into two independent sub-channels. The DDR Sub-System Driveway
+implements separate PMUs for each sub-channel to monitor various performance
+metrics.
+
+The Driveway PMU devices are named as ali_drw_<sys_base_addr> with perf.
+For example, ali_drw_21000 and ali_drw_21080 are two PMU devices for two
+sub-channels of the same channel in die 0. And the PMU device of die 1 is
+prefixed with ali_drw_400XXXXX, e.g. ali_drw_40021000.
+
+Each sub-channel has 36 PMU counters in total, which is classified into
+four groups:
+
+- Group 0: PMU Cycle Counter. This group has one pair of counters
+ pmu_cycle_cnt_low and pmu_cycle_cnt_high, that is used as the cycle count
+ based on DDRC core clock.
+
+- Group 1: PMU Bandwidth Counters. This group has 8 counters that are used
+ to count the total access number of either the eight bank groups in a
+ selected rank, or four ranks separately in the first 4 counters. The base
+ transfer unit is 64B.
+
+- Group 2: PMU Retry Counters. This group has 10 counters, that intend to
+ count the total retry number of each type of uncorrectable error.
+
+- Group 3: PMU Common Counters. This group has 16 counters, that are used
+ to count the common events.
+
+For now, the Driveway PMU driver only uses counters in group 0 and group 3.
+
+The DDR Controller (DDRCTL) and DDR PHY combine to create a complete solution
+for connecting an SoC application bus to DDR memory devices. The DDRCTL
+receives transactions Host Interface (HIF) which is custom-defined by Synopsys.
+These transactions are queued internally and scheduled for access while
+satisfying the SDRAM protocol timing requirements, transaction priorities, and
+dependencies between the transactions. The DDRCTL in turn issues commands on
+the DDR PHY Interface (DFI) to the PHY module, which launches and captures data
+to and from the SDRAM. The driveway PMUs have hardware logic to gather
+statistics and performance logging signals on HIF, DFI, etc.
+
+By counting the READ, WRITE and RMW commands sent to the DDRC through the HIF
+interface, we could calculate the bandwidth. Example usage of counting memory
+data bandwidth::
+
+ perf stat \
+ -e ali_drw_21000/hif_wr/ \
+ -e ali_drw_21000/hif_rd/ \
+ -e ali_drw_21000/hif_rmw/ \
+ -e ali_drw_21000/cycle/ \
+ -e ali_drw_21080/hif_wr/ \
+ -e ali_drw_21080/hif_rd/ \
+ -e ali_drw_21080/hif_rmw/ \
+ -e ali_drw_21080/cycle/ \
+ -e ali_drw_23000/hif_wr/ \
+ -e ali_drw_23000/hif_rd/ \
+ -e ali_drw_23000/hif_rmw/ \
+ -e ali_drw_23000/cycle/ \
+ -e ali_drw_23080/hif_wr/ \
+ -e ali_drw_23080/hif_rd/ \
+ -e ali_drw_23080/hif_rmw/ \
+ -e ali_drw_23080/cycle/ \
+ -e ali_drw_25000/hif_wr/ \
+ -e ali_drw_25000/hif_rd/ \
+ -e ali_drw_25000/hif_rmw/ \
+ -e ali_drw_25000/cycle/ \
+ -e ali_drw_25080/hif_wr/ \
+ -e ali_drw_25080/hif_rd/ \
+ -e ali_drw_25080/hif_rmw/ \
+ -e ali_drw_25080/cycle/ \
+ -e ali_drw_27000/hif_wr/ \
+ -e ali_drw_27000/hif_rd/ \
+ -e ali_drw_27000/hif_rmw/ \
+ -e ali_drw_27000/cycle/ \
+ -e ali_drw_27080/hif_wr/ \
+ -e ali_drw_27080/hif_rd/ \
+ -e ali_drw_27080/hif_rmw/ \
+ -e ali_drw_27080/cycle/ -- sleep 10
+
+The average DRAM bandwidth can be calculated as follows:
+
+- Read Bandwidth = perf_hif_rd * DDRC_WIDTH * DDRC_Freq / DDRC_Cycle
+- Write Bandwidth = (perf_hif_wr + perf_hif_rmw) * DDRC_WIDTH * DDRC_Freq / DDRC_Cycle
+
+Here, DDRC_WIDTH = 64 bytes.
+
+The current driver does not support sampling. So "perf record" is
+unsupported. Also attach to a task is unsupported as the events are all
+uncore.
diff --git a/Documentation/admin-guide/perf/index.rst b/Documentation/admin-guide/perf/index.rst
index 9c9ece88ce53..793e1970bc05 100644
--- a/Documentation/admin-guide/perf/index.rst
+++ b/Documentation/admin-guide/perf/index.rst
@@ -18,3 +18,4 @@ Performance monitor support
xgene-pmu
arm_dsu_pmu
thunderx2-pmu
+ alibaba_pmu