From 2bc6b218717b9d08f466f88209251d54bc09b207 Mon Sep 17 00:00:00 2001 From: Fuad Tabba Date: Tue, 22 Sep 2026 19:14:30 +0100 Subject: arm64/boot: Disable trapping of PMZR_EL0 writes to EL2 __init_el2_fgt2() writes one mask to both HDFGRTR2_EL2 and HDFGWTR2_EL2. PMZR_EL0 is write-only, so its trap bit, nPMZR_EL0, exists only in HDFGWTR2_EL2 and is therefore never set: a PMZR_EL0 write from the host traps to EL2, where the nVHE hypervisor has no handler and BUG()s. The kernel never writes PMZR_EL0, but kernel.perf_user_access=1 has the PMU driver set PMUSERENR_EL0.UEN for a task with a user-read event, so a write from EL0 reaches the trap and takes the host down without a panic message. Accumulate the HDFGWTR2_EL2 bits separately, as __init_el2_fgt() already does for HDFGWTR_EL2, and set nPMZR_EL0 with the other FEAT_PMUv3p9 bits. Fixes: 858c7bfcb35e1 ("arm64/boot: Enable EL2 requirements for FEAT_PMUv3p9") Cc: stable@vger.kernel.org Signed-off-by: Fuad Tabba Reviewed-by: Anshuman Khandual Reviewed-by: Oliver Upton Signed-off-by: Will Deacon --- Documentation/tools/rtla/rtla.rst | 52 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 52 insertions(+) create mode 100644 Documentation/tools/rtla/rtla.rst (limited to 'Documentation/tools/rtla/rtla.rst') diff --git a/Documentation/tools/rtla/rtla.rst b/Documentation/tools/rtla/rtla.rst new file mode 100644 index 000000000..6df1296b8 --- /dev/null +++ b/Documentation/tools/rtla/rtla.rst @@ -0,0 +1,52 @@ +========= +rtla +========= +-------------------------------- +Real-time Linux Analysis tool +-------------------------------- + +:Manual section: 1 + +SYNOPSIS +======== +**rtla** *COMMAND* [*OPTIONS*] + +DESCRIPTION +=========== +The **rtla** is a meta-tool that includes a set of commands that aims to +analyze the real-time properties of Linux. But instead of testing Linux +as a black box, **rtla** leverages kernel tracing capabilities to provide +precise information about the properties and root causes of unexpected +results. + +COMMANDS +======== +**hwnoise** + + Detect and quantify hardware-related noise. + +**osnoise** + + Gives information about the operating system noise (osnoise). + +**timerlat** + + Measures the IRQ and thread timer latency. + +OPTIONS +======= +**-h**, **--help** + + Display the help text. + +For other options, see the man page for the corresponding command. + +SEE ALSO +======== +**rtla-hwnoise**\(1), **rtla-osnoise**\(1), **rtla-timerlat**\(1) + +AUTHOR +====== +Daniel Bristot de Oliveira + +.. include:: common_appendix.txt -- cgit v1.3.1