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| author | Fuad Tabba <fuad.tabba@linux.dev> | 2026-09-22 19:14:30 +0100 |
|---|---|---|
| committer | Will Deacon <will@kernel.org> | 2026-09-23 12:34:30 +0000 |
| commit | 2bc6b218717b9d08f466f88209251d54bc09b207 (patch) | |
| tree | cb91c941eccb15f94cbec4e96aa3a9c8736b5d66 /Documentation/admin-guide/sysctl/sunrpc.rst | |
| download | linux-stable-2bc6b218717b9d08f466f88209251d54bc09b207.tar.gz linux-stable-2bc6b218717b9d08f466f88209251d54bc09b207.zip | |
arm64/boot: Disable trapping of PMZR_EL0 writes to EL2grafted
__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 <fuad.tabba@linux.dev>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: Oliver Upton <oupton@kernel.org>
Signed-off-by: Will Deacon <will@kernel.org>
Diffstat (limited to 'Documentation/admin-guide/sysctl/sunrpc.rst')
| -rw-r--r-- | Documentation/admin-guide/sysctl/sunrpc.rst | 25 |
1 files changed, 25 insertions, 0 deletions
diff --git a/Documentation/admin-guide/sysctl/sunrpc.rst b/Documentation/admin-guide/sysctl/sunrpc.rst new file mode 100644 index 000000000..09780a682 --- /dev/null +++ b/Documentation/admin-guide/sysctl/sunrpc.rst @@ -0,0 +1,25 @@ +=================================== +Documentation for /proc/sys/sunrpc/ +=================================== + +kernel version 2.2.10 + +Copyright (c) 1998, 1999, Rik van Riel <riel@nl.linux.org> + +For general info and legal blurb, please look in index.rst. + +------------------------------------------------------------------------------ + +This file contains the documentation for the sysctl files in +/proc/sys/sunrpc and is valid for Linux kernel version 2.2. + +The files in this directory can be used to (re)set the debug +flags of the SUN Remote Procedure Call (RPC) subsystem in +the Linux kernel. This stuff is used for NFS, KNFSD and +maybe a few other things as well. + +The files in there are used to control the debugging flags: +rpc_debug, nfs_debug, nfsd_debug and nlm_debug. + +These flags are for kernel hackers only. You should read the +source code in net/sunrpc/ for more information. |