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Conor Dooley d9f15a9de4 Revert "clocksource/drivers/riscv: Events are stopped during CPU suspend"
This reverts commit 232ccac1bd.

On the subject of suspend, the RISC-V SBI spec states:

  This does not cover whether any given events actually reach the hart or
  not, just what the hart will do if it receives an event. On PolarFire
  SoC, and potentially other SiFive based implementations, events from the
  RISC-V timer do reach a hart during suspend. This is not the case for the
  implementation on the Allwinner D1 - there timer events are not received
  during suspend.

To fix this, the CLOCK_EVT_FEAT_C3STOP (mis)feature was enabled for the
timer driver - but this has broken both RCU stall detection and timers
generally on PolarFire SoC and potentially other SiFive based
implementations.

If an AXI read to the PCIe controller on PolarFire SoC times out, the
system will stall, however, with CLOCK_EVT_FEAT_C3STOP active, the system
just locks up without RCU stalling:

	io scheduler mq-deadline registered
	io scheduler kyber registered
	microchip-pcie 2000000000.pcie: host bridge /soc/pcie@2000000000 ranges:
	microchip-pcie 2000000000.pcie:      MEM 0x2008000000..0x2087ffffff -> 0x0008000000
	microchip-pcie 2000000000.pcie: sec error in pcie2axi buffer
	microchip-pcie 2000000000.pcie: ded error in pcie2axi buffer
	microchip-pcie 2000000000.pcie: axi read request error
	microchip-pcie 2000000000.pcie: axi read timeout
	microchip-pcie 2000000000.pcie: sec error in pcie2axi buffer
	microchip-pcie 2000000000.pcie: ded error in pcie2axi buffer
	microchip-pcie 2000000000.pcie: sec error in pcie2axi buffer
	microchip-pcie 2000000000.pcie: ded error in pcie2axi buffer
	microchip-pcie 2000000000.pcie: sec error in pcie2axi buffer
	microchip-pcie 2000000000.pcie: ded error in pcie2axi buffer
	Freeing initrd memory: 7332K

Similarly issues were reported with clock_nanosleep() - with a test app
that sleeps each cpu for 6, 5, 4, 3 ms respectively, HZ=250 & the blamed
commit in place, the sleep times are rounded up to the next jiffy:

== CPU: 1 ==      == CPU: 2 ==      == CPU: 3 ==      == CPU: 4 ==
Mean: 7.974992    Mean: 7.976534    Mean: 7.962591    Mean: 3.952179
Std Dev: 0.154374 Std Dev: 0.156082 Std Dev: 0.171018 Std Dev: 0.076193
Hi: 9.472000      Hi: 10.495000     Hi: 8.864000      Hi: 4.736000
Lo: 6.087000      Lo: 6.380000      Lo: 4.872000      Lo: 3.403000
Samples: 521      Samples: 521      Samples: 521      Samples: 521

Fortunately, the D1 has a second timer, which is "currently used in
preference to the RISC-V/SBI timer driver" so a revert here does not
hurt operation of D1 in its current form.

Ultimately, a DeviceTree property (or node) will be added to encode the
behaviour of the timers, but until then revert the addition of
CLOCK_EVT_FEAT_C3STOP.

Fixes: 232ccac1bd ("clocksource/drivers/riscv: Events are stopped during CPU suspend")
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Palmer Dabbelt <palmer@rivosinc.com>
Acked-by: Palmer Dabbelt <palmer@rivosinc.com>
Acked-by: Samuel Holland <samuel@sholland.org>
Link: https://lore.kernel.org/linux-riscv/YzYTNQRxLr7Q9JR0@spud/
Link: https://github.com/riscv-non-isa/riscv-sbi-doc/issues/98/
Link: https://lore.kernel.org/linux-riscv/bf6d3b1f-f703-4a25-833e-972a44a04114@sholland.org/
Link: https://lore.kernel.org/r/20221122121620.3522431-1-conor.dooley@microchip.com
2022-12-01 12:05:29 +01:00
arch - ioremap: mask out the bits which are not part of the physical address 2022-11-27 11:59:14 -08:00
block block-6.1-2022-11-25 2022-11-25 17:50:57 -08:00
certs certs: make system keyring depend on built-in x509 parser 2022-09-24 04:31:18 +09:00
crypto treewide: use get_random_bytes() when possible 2022-10-11 17:42:58 -06:00
Documentation Char/Misc driver fixes for 6.1-rc7 2022-11-27 12:17:10 -08:00
drivers Revert "clocksource/drivers/riscv: Events are stopped during CPU suspend" 2022-12-01 12:05:29 +01:00
fs Amir's copy_file_range() fix 2022-11-27 12:40:06 -08:00
include Amir's copy_file_range() fix 2022-11-27 12:40:06 -08:00
init init/Kconfig: fix CC_HAS_ASM_GOTO_TIED_OUTPUT test with dash 2022-11-22 22:42:38 +09:00
io_uring io_uring: clear TIF_NOTIFY_SIGNAL if set and task_work not available 2022-11-25 10:55:08 -07:00
ipc ipc/shm: call underlying open/close vm_ops 2022-11-22 18:50:42 -08:00
kernel - Two more fixes to the perf sigtrap handling: 2022-11-27 11:53:41 -08:00
lib Char/Misc driver fixes for 6.1-rc7 2022-11-27 12:17:10 -08:00
LICENSES LICENSES/LGPL-2.1: Add LGPL-2.1-or-later as valid identifiers 2021-12-16 14:33:10 +01:00
mm 24 hotfixes. 8 marked cc:stable and 16 for post-6.0 issues. 2022-11-25 10:18:25 -08:00
net Networking fixes for 6.1-rc7, including fixes from rxrpc, netfilter and 2022-11-24 11:19:20 -08:00
rust Kbuild: add Rust support 2022-09-28 09:02:20 +02:00
samples VFIO updates for v6.1-rc1 2022-10-12 14:46:48 -07:00
scripts - Handle different output of readelf on different distros running 2022-11-27 12:08:17 -08:00
security lsm/stable-6.1 PR 20221031 2022-10-31 12:09:42 -07:00
sound ASoC: Fixes for v6.1 2022-11-23 17:14:10 +01:00
tools x86: 2022-11-27 09:08:40 -08:00
usr usr/gen_init_cpio.c: remove unnecessary -1 values from int file 2022-10-03 14:21:44 -07:00
virt Merge branch 'kvm-dwmw2-fixes' into HEAD 2022-11-23 18:59:45 -05:00
.clang-format PCI/DOE: Add DOE mailbox support functions 2022-07-19 15:38:04 -07:00
.cocciconfig
.get_maintainer.ignore get_maintainer: add Alan to .get_maintainer.ignore 2022-08-20 15:17:44 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore Kbuild: add Rust support 2022-09-28 09:02:20 +02:00
.mailmap 24 hotfixes. 8 marked cc:stable and 16 for post-6.0 issues. 2022-11-25 10:18:25 -08:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Remove Michal Marek from Kbuild maintainers 2022-11-16 14:53:00 +09:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS s390 updates for 6.1-rc7 2022-11-25 12:37:24 -08:00
Makefile Linux 6.1-rc7 2022-11-27 13:31:48 -08:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.