Re: [PATCH 17/36] acpi_idle: Remove tracing
From: "Rafael J. Wysocki" <rafael@kernel.org>
Date: 2022-07-06 13:59:47
Also in:
linux-acpi, linux-alpha, linux-arch, linux-arm-msm, linux-clk, linux-m68k, linux-mips, linux-omap, linux-perf-users, linux-pm, linux-riscv, linux-s390, linux-sh, linux-tegra, linux-um, lkml, rcu, sparclinux, virtualization, xen-devel
ieu.desnoyers@efficios.com>, Frederic Weisbecker [off-list ref], Len Brown [off-list ref], linux-xtensa@linux-xtensa.org, Sascha Hauer [off-list ref], Vasily Gorbik [off-list ref], linux-arm-msm [off-list ref], linux-alpha@vger.kernel.org, linux-m68k [off-list ref], Stafford Horne [off-list ref], Linux ARM [off-list ref], Chris Zankel [off-list ref], Stephen Boyd [off-list ref], dinguyen@kernel.org, Daniel Bristot de Oliveira [off-list ref], Alexander Shishkin [off-list ref], Lorenzo Pieralisi [off-list ref], Rasmus Villemoes [off-list ref], Joel Fernandes [off-list ref], Will Deacon [off-list ref], Boris Ostrovsky [off-list ref], Kevin Hilman [off-list ref], linux-csky@vger.kernel.org, pv-drivers@vmware.com, linux-snps-arc@lists.infradead.org, Mel Gorman [off-list ref], Jacob Pan <jacob.jun.pan@linux.inte l.com>, Arnd Bergmann [off-list ref], ulli.kroll@googlemail.com, vgupta@kernel.org, linux-clk [off-list ref], Josh Triplett [off-list ref], Steven Rostedt [off-list ref], rcu@vger.kernel.org, Borislav Petkov [off-list ref], bcain@quicinc.com, Thomas Bogendoerfer [off-list ref], Parisc List [off-list ref], Sudeep Holla [off-list ref], Shawn Guo [off-list ref], David Miller [off-list ref], Rich Felker [off-list ref], Tony Lindgren [off-list ref], amakhalov@vmware.com, Bjorn Andersson [off-list ref], "H. Peter Anvin" [off-list ref], sparclinux@vger.kernel.org, linux-hexagon@vger.kernel.org, linux-riscv [off-list ref], anton.ivanov@cambridgegreys.com, jonas@southpole.se, Yury Norov [off-list ref], Richard Weinberger [off-list ref], the arch/x86 maintainers [off-list ref], Russell King - ARM Linux [off-list ref], Ingo Molnar [off-list ref], Al bert Ou [off-list ref], "Paul E. McKenney" < paulmck@kernel.org>, Heiko Carstens [off-list ref], stefan.kristiansson@saunalahti.fi, openrisc@lists.librecores.org, Paul Walmsley [off-list ref], linux-tegra [off-list ref], namhyung@kernel.org, Andy Shevchenko [off-list ref], jpoimboe@kernel.org, Juergen Gross [off-list ref], Michal Simek [off-list ref], "open list:BROADCOM NVRAM DRIVER" [off-list ref], Palmer Dabbelt [off-list ref], Anup Patel [off-list ref], ink@jurassic.park.msu.ru, Johannes Berg [off-list ref], linuxppc-dev [off-list ref] Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" [off-list ref] On Wed, Jun 8, 2022 at 4:47 PM Peter Zijlstra [off-list ref] wrote:
All the idle routines are called with RCU disabled, as such there must not be any tracing inside. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
This actually does some additional code duplication cleanup which would be good to mention in the changelog. Or even move to a separate patch for that matter. Otherwise LGTM.
quoted hunk ↗ jump to hunk
--- drivers/acpi/processor_idle.c | 24 +++++++++++++----------- 1 file changed, 13 insertions(+), 11 deletions(-)--- a/drivers/acpi/processor_idle.c +++ b/drivers/acpi/processor_idle.c@@ -108,8 +108,8 @@ static const struct dmi_system_id proces static void __cpuidle acpi_safe_halt(void) { if (!tif_need_resched()) { - safe_halt(); - local_irq_disable(); + raw_safe_halt(); + raw_local_irq_disable(); } }@@ -524,16 +524,21 @@ static int acpi_idle_bm_check(void) return bm_status; } -static void wait_for_freeze(void) +static __cpuidle void io_idle(unsigned long addr) { + /* IO port based C-state */ + inb(addr); + #ifdef CONFIG_X86 /* No delay is needed if we are in guest */ if (boot_cpu_has(X86_FEATURE_HYPERVISOR)) return; #endif - /* Dummy wait op - must do something useless after P_LVL2 read - because chipsets cannot guarantee that STPCLK# signal - gets asserted in time to freeze execution properly. */ + /* + * Dummy wait op - must do something useless after P_LVL2 read + * because chipsets cannot guarantee that STPCLK# signal + * gets asserted in time to freeze execution properly. + */ inl(acpi_gbl_FADT.xpm_timer_block.address); }@@ -553,9 +558,7 @@ static void __cpuidle acpi_idle_do_entry } else if (cx->entry_method == ACPI_CSTATE_HALT) { acpi_safe_halt(); } else { - /* IO port based C-state */ - inb(cx->address); - wait_for_freeze(); + io_idle(cx->address); } perf_lopwr_cb(false);@@ -577,8 +580,7 @@ static int acpi_idle_play_dead(struct cp if (cx->entry_method == ACPI_CSTATE_HALT) safe_halt(); else if (cx->entry_method == ACPI_CSTATE_SYSTEMIO) { - inb(cx->address); - wait_for_freeze(); + io_idle(cx->address); } else return -ENODEV;