Because CONFIG_ soup.
Fixes: 6e1d2bc675bd ("intel_idle: Fix intel_idle() vs tracing")
Reported-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20201130115402.GO3040@hirez.programming.kicks-ass.net
cpuidle->enter() callbacks should not call into tracing because RCU has already been disabled. Instead of doing the broadcast thing itself, simply advertise to the cpuidle core that those states stop the timer. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Link: https://lkml.kernel.org/r/20201123143510.GR3021@hirez.programming.kicks-ass.net
Currently intel_idle driver gets the c-state information from ACPI
_CST if the processor model is not recognized by it. However the
c-state in _CST starts with index 1 which is different from the
index in intel_idle driver's internal c-state table.
While intel_idle_max_cstate_reached() was previously introduced to
deal with intel_idle driver's internal c-state table, re-using
this function directly on _CST is incorrect.
Fix this by subtracting 1 from the index when checking max_cstate
in the _CST case.
For example, append intel_idle.max_cstate=1 in boot command line,
Before the patch:
grep . /sys/devices/system/cpu/cpu0/cpuidle/state*/name
POLL
After the patch:
grep . /sys/devices/system/cpu/cpu0/cpuidle/state*/name
/sys/devices/system/cpu/cpu0/cpuidle/state0/name:POLL
/sys/devices/system/cpu/cpu0/cpuidle/state1/name:C1_ACPI
Fixes: 18734958e9bf ("intel_idle: Use ACPI _CST for processor models without C-state tables")
Reported-by: Pengfei Xu <pengfei.xu@intel.com>
Cc: 5.6+ <stable@vger.kernel.org> # 5.6+
Signed-off-by: Chen Yu <yu.c.chen@intel.com>
[ rjw: Changelog edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
e6d4f08a6776 ("intel_idle: Use ACPI _CST on server systems") avoids
enabling c-states that have been disabled by the platform with the
exception of C1E.
Unfortunately, BIOS implementations are not always consistent in terms
of how capabilities are advertised and control cannot always be handed
over. If control cannot be handed over then intel_idle reports that "ACPI
_CST not found or not usable" but does not clear acpi_state_table.count
meaning the information is still partially used.
This patch ignores ACPI information if CST control cannot be requested from
the platform. This was only observed on a number of Haswell platforms that
had identical CPUs but not identical BIOS versions. While this problem
may be rare overall, 24 separate test cases bisected to this specific
commit across 4 separate test machines and is worth addressing. If the
situation occurs, the kernel behaves as it did before commit e6d4f08a6776
and uses any c-states that are discovered.
The affected test cases were all ones that involved a small number of
processes -- exec microbenchmark, pipe microbenchmark, git test suite,
netperf, tbench with one client and system call microbenchmark. Each
case benefits from being able to use turboboost which is prevented if the
lower c-states are unavailable. This may mask real regressions specific
to older hardware so it is worth addressing.
C-state status before and after the patch
5.9.0-vanilla POLL latency:0 disabled:0 default:enabled
5.9.0-vanilla C1 latency:2 disabled:0 default:enabled
5.9.0-vanilla C1E latency:10 disabled:0 default:enabled
5.9.0-vanilla C3 latency:33 disabled:1 default:disabled
5.9.0-vanilla C6 latency:133 disabled:1 default:disabled
5.9.0-ignore-cst-v1r1 POLL latency:0 disabled:0 default:enabled
5.9.0-ignore-cst-v1r1 C1 latency:2 disabled:0 default:enabled
5.9.0-ignore-cst-v1r1 C1E latency:10 disabled:0 default:enabled
5.9.0-ignore-cst-v1r1 C3 latency:33 disabled:0 default:enabled
5.9.0-ignore-cst-v1r1 C6 latency:133 disabled:0 default:enabled
Patch enables C3/C6.
Netperf UDP_STREAM
netperf-udp
5.5.0 5.9.0
vanilla ignore-cst-v1r1
Hmean send-64 193.41 ( 0.00%) 226.54 * 17.13%*
Hmean send-128 392.16 ( 0.00%) 450.54 * 14.89%*
Hmean send-256 769.94 ( 0.00%) 881.85 * 14.53%*
Hmean send-1024 2994.21 ( 0.00%) 3468.95 * 15.85%*
Hmean send-2048 5725.60 ( 0.00%) 6628.99 * 15.78%*
Hmean send-3312 8468.36 ( 0.00%) 10288.02 * 21.49%*
Hmean send-4096 10135.46 ( 0.00%) 12387.57 * 22.22%*
Hmean send-8192 17142.07 ( 0.00%) 19748.11 * 15.20%*
Hmean send-16384 28539.71 ( 0.00%) 30084.45 * 5.41%*
Fixes: e6d4f08a6776 ("intel_idle: Use ACPI _CST on server systems")
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Cc: 5.6+ <stable@vger.kernel.org> # 5.6+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Intel SDM does not explicitly say that entering a C-state via MWAIT will implicitly flush CPU caches as appropriate for that C-state. However, documentation for individual Intel CPU generations does mention this behavior. Since intel_idle binds to any Intel CPU with MWAIT, list this assumption of MWAIT behavior. In passing, reword opening comment to make it clear that the driver can load on any old and future Intel CPU with MWAIT. Signed-off-by: Alexander Monakov <amonakov@ispras.ru> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This allows moving the leave_mm() call into generic code before rcu_idle_enter(). Gets rid of more trace_*_rcuidle() users. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Tested-by: Marco Elver <elver@google.com> Link: https://lkml.kernel.org/r/20200821085348.369441600@infradead.org
Pull uninitialized_var() macro removal from Kees Cook: "This is long overdue, and has hidden too many bugs over the years. The series has several "by hand" fixes, and then a trivial treewide replacement. - Clean up non-trivial uses of uninitialized_var() - Update documentation and checkpatch for uninitialized_var() removal - Treewide removal of uninitialized_var()" * tag 'uninit-macro-v5.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: compiler: Remove uninitialized_var() macro treewide: Remove uninitialized_var() usage checkpatch: Remove awareness of uninitialized_var() macro mm/debug_vm_pgtable: Remove uninitialized_var() usage f2fs: Eliminate usage of uninitialized_var() macro media: sur40: Remove uninitialized_var() usage KVM: PPC: Book3S PR: Remove uninitialized_var() usage clk: spear: Remove uninitialized_var() usage clk: st: Remove uninitialized_var() usage spi: davinci: Remove uninitialized_var() usage ide: Remove uninitialized_var() usage rtlwifi: rtl8192cu: Remove uninitialized_var() usage b43: Remove uninitialized_var() usage drbd: Remove uninitialized_var() usage x86/mm/numa: Remove uninitialized_var() usage docs: deprecated.rst: Add uninitialized_var()
On ICX platform, the C1E auto-promotion is enabled by default. As a result, the CPU might fall into C1E more offen than previous platforms. Besides, the C1E is not exposed to sysfs on ICX, which is inconsistent with previous server platforms. So disable C1E auto-promotion and expose C1E as a separate idle state, so the C1E and C6 can be disabled via sysfs when necessary. Beside C1 and C1E, the exit latency of C6 was measured by a dedicated tool. However the exit latency(41us) exposed by _CST is much smaller than the one we measured(128us). This is probably due to the _CST uses the exit latency when woken up from PC0+C6, rather than PC6+C6 when C6 was measured. Choose the latter as we need the longest latency in theory. Reported-by: kernel test robot <lkp@intel.com> Tested-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com> Acked-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com> Reviewed-by: Zhang Rui <rui.zhang@intel.com> Signed-off-by: Chen Yu <yu.c.chen@intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Control Flow Integrity(CFI) is a security mechanism that disallows
changes to the original control flow graph of a compiled binary,
making it significantly harder to perform such attacks.
init_state_node() assign same function callback to different
function pointer declarations.
static int init_state_node(struct cpuidle_state *idle_state,
const struct of_device_id *matches,
struct device_node *state_node) { ...
idle_state->enter = match_id->data; ...
idle_state->enter_s2idle = match_id->data; }
Function declarations:
struct cpuidle_state { ...
int (*enter) (struct cpuidle_device *dev,
struct cpuidle_driver *drv,
int index);
void (*enter_s2idle) (struct cpuidle_device *dev,
struct cpuidle_driver *drv,
int index); };
In this case, either enter() or enter_s2idle() would cause CFI check
failed since they use same callee.
Align function prototype of enter() since it needs return value for
some use cases. The return value of enter_s2idle() is no
need currently.
Signed-off-by: Neal Liu <neal.liu@mediatek.com>
Reviewed-by: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Using uninitialized_var() is dangerous as it papers over real bugs[1] (or can in the future), and suppresses unrelated compiler warnings (e.g. "unused variable"). If the compiler thinks it is uninitialized, either simply initialize the variable or make compiler changes. In preparation for removing[2] the[3] macro[4], remove all remaining needless uses with the following script: git grep '\buninitialized_var\b' | cut -d: -f1 | sort -u | \ xargs perl -pi -e \ 's/\buninitialized_var\(([^\)]+)\)/\1/g; s:\s*/\* (GCC be quiet|to make compiler happy) \*/$::g;' drivers/video/fbdev/riva/riva_hw.c was manually tweaked to avoid pathological white-space. No outstanding warnings were found building allmodconfig with GCC 9.3.0 for x86_64, i386, arm64, arm, powerpc, powerpc64le, s390x, mips, sparc64, alpha, and m68k. [1] https://lore.kernel.org/lkml/20200603174714.192027-1-glider@google.com/ [2] https://lore.kernel.org/lkml/CA+55aFw+Vbj0i=1TGqCR5vQkCzWJ0QxK6CernOU6eedsudAixw@mail.gmail.com/ [3] https://lore.kernel.org/lkml/CA+55aFwgbgqhbp1fkxvRKEpzyR5J8n1vKT1VZdz9knmPuXhOeg@mail.gmail.com/ [4] https://lore.kernel.org/lkml/CA+55aFz2500WfbKXAx8s67wrm9=yVJu65TpLgN_ybYNv0VEOKA@mail.gmail.com/ Reviewed-by: Leon Romanovsky <leonro@mellanox.com> # drivers/infiniband and mlx4/mlx5 Acked-by: Jason Gunthorpe <jgg@mellanox.com> # IB Acked-by: Kalle Valo <kvalo@codeaurora.org> # wireless drivers Reviewed-by: Chao Yu <yuchao0@huawei.com> # erofs Signed-off-by: Kees Cook <keescook@chromium.org>