From: Keith Packard <keithpac@amazon.com>
To: linux-kernel@vger.kernel.org
Cc: "Abbott Liu" <liuwenliang@huawei.com>,
"Andrew Morton" <akpm@linux-foundation.org>,
"Andrey Ryabinin" <ryabinin.a.a@gmail.com>,
"Anshuman Khandual" <anshuman.khandual@arm.com>,
"Ard Biesheuvel" <ardb@kernel.org>,
"Arnd Bergmann" <arnd@arndb.de>,
"Bjorn Andersson" <bjorn.andersson@linaro.org>,
"Christoph Lameter" <cl@linux.com>,
"Dennis Zhou" <dennis@kernel.org>,
"Geert Uytterhoeven" <geert+renesas@glider.be>,
"Jens Axboe" <axboe@kernel.dk>, "Joe Perches" <joe@perches.com>,
"Kees Cook" <keescook@chromium.org>,
"Keith Packard" <keithpac@amazon.com>,
"Krzysztof Kozlowski" <krzysztof.kozlowski@canonical.com>,
"Linus Walleij" <linus.walleij@linaro.org>,
linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org,
"Manivannan Sadhasivam" <mani@kernel.org>,
"Marc Zyngier" <maz@kernel.org>,
"Masahiro Yamada" <masahiroy@kernel.org>,
"Mike Rapoport" <rppt@kernel.org>,
"Nathan Chancellor" <nathan@kernel.org>,
"Nick Desaulniers" <ndesaulniers@google.com>,
"Nick Desaulniers" <ndesaulniers@gooogle.com>,
"Nicolas Pitre" <nico@fluxnic.net>,
"Russell King" <linux@armlinux.org.uk>,
"Tejun Heo" <tj@kernel.org>,
"Thomas Gleixner" <tglx@linutronix.de>,
"Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>,
"Valentin Schneider" <valentin.schneider@arm.com>,
"Viresh Kumar" <viresh.kumar@linaro.org>,
"Wolfram Sang (Renesas)" <wsa+renesas@sang-engineering.com>,
"YiFei Zhu" <yifeifz2@illinois.edu>
Subject: [PATCH 5/7] ARM: Stop using TPIDRPRW to hold per_cpu_offset
Date: Tue, 7 Sep 2021 15:00:36 -0700 [thread overview]
Message-ID: <20210907220038.91021-6-keithpac@amazon.com> (raw)
In-Reply-To: <20210907220038.91021-1-keithpac@amazon.com>
We're going to store TPIDRPRW here instead
Signed-off-by: Keith Packard <keithpac@amazon.com>
---
arch/arm/include/asm/percpu.h | 31 -------------------------------
arch/arm/kernel/setup.c | 7 -------
arch/arm/kernel/smp.c | 3 ---
3 files changed, 41 deletions(-)
diff --git a/arch/arm/include/asm/percpu.h b/arch/arm/include/asm/percpu.h
index e2fcb3cfd3de..eeafcd6a3e01 100644
--- a/arch/arm/include/asm/percpu.h
+++ b/arch/arm/include/asm/percpu.h
@@ -7,37 +7,6 @@
register unsigned long current_stack_pointer asm ("sp");
-/*
- * Same as asm-generic/percpu.h, except that we store the per cpu offset
- * in the TPIDRPRW. TPIDRPRW only exists on V6K and V7
- */
-#if defined(CONFIG_SMP) && !defined(CONFIG_CPU_V6)
-static inline void set_my_cpu_offset(unsigned long off)
-{
- /* Set TPIDRPRW */
- asm volatile("mcr p15, 0, %0, c13, c0, 4" : : "r" (off) : "memory");
-}
-
-static inline unsigned long __my_cpu_offset(void)
-{
- unsigned long off;
-
- /*
- * Read TPIDRPRW.
- * We want to allow caching the value, so avoid using volatile and
- * instead use a fake stack read to hazard against barrier().
- */
- asm("mrc p15, 0, %0, c13, c0, 4" : "=r" (off)
- : "Q" (*(const unsigned long *)current_stack_pointer));
-
- return off;
-}
-#define __my_cpu_offset __my_cpu_offset()
-#else
-#define set_my_cpu_offset(x) do {} while(0)
-
-#endif /* CONFIG_SMP */
-
#include <asm-generic/percpu.h>
#endif /* _ASM_ARM_PERCPU_H_ */
diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c
index ca0201635fac..d0dc60afe54f 100644
--- a/arch/arm/kernel/setup.c
+++ b/arch/arm/kernel/setup.c
@@ -590,13 +590,6 @@ void __init smp_setup_processor_id(void)
for (i = 1; i < nr_cpu_ids; ++i)
cpu_logical_map(i) = i == cpu ? 0 : i;
- /*
- * clear __my_cpu_offset on boot CPU to avoid hang caused by
- * using percpu variable early, for example, lockdep will
- * access percpu variable inside lock_release
- */
- set_my_cpu_offset(0);
-
pr_info("Booting Linux on physical CPU 0x%x\n", mpidr);
}
diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c
index 5e999f1f1aea..8ccf10b34f08 100644
--- a/arch/arm/kernel/smp.c
+++ b/arch/arm/kernel/smp.c
@@ -410,8 +410,6 @@ asmlinkage void secondary_start_kernel(unsigned int cpu, struct task_struct *tas
{
struct mm_struct *mm = &init_mm;
- set_my_cpu_offset(per_cpu_offset(cpu));
-
secondary_biglittle_init();
/*
@@ -495,7 +493,6 @@ void __init smp_cpus_done(unsigned int max_cpus)
void __init smp_prepare_boot_cpu(void)
{
- set_my_cpu_offset(per_cpu_offset(smp_processor_id()));
}
void __init smp_prepare_cpus(unsigned int max_cpus)
--
2.33.0
next prev parent reply other threads:[~2021-09-07 22:01 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20210904060908.1310204-1-keithp@keithp.com>
2021-09-07 22:00 ` [PATCH 0/7] ARM: support THREAD_INFO_IN_TASK (v3) Keith Packard
2021-09-07 22:00 ` [PATCH 1/7] ARM: Pass cpu number to secondary_start_kernel Keith Packard
2021-09-07 22:00 ` [PATCH 2/7] ARM: Pass task " Keith Packard
2021-09-07 22:00 ` [PATCH 3/7] ARM: Use smp_processor_id() in vfp_pm_suspend instead of ti->cpu Keith Packard
2021-09-07 22:00 ` [PATCH 4/7] ARM: Use hack from powerpc to get current cpu number Keith Packard
2021-09-08 7:45 ` Ard Biesheuvel
2021-09-07 22:00 ` Keith Packard [this message]
2021-09-09 13:54 ` [PATCH 5/7] ARM: Stop using TPIDRPRW to hold per_cpu_offset Ard Biesheuvel
2021-09-07 22:00 ` [PATCH 6/7] ARM: Use TPIDRPRW for current Keith Packard
2021-09-09 13:56 ` Ard Biesheuvel
2021-09-07 22:00 ` [PATCH 7/7] ARM: Move thread_info into task_struct (v7 only) Keith Packard
2021-09-08 7:01 ` [PATCH 0/7] ARM: support THREAD_INFO_IN_TASK (v3) Krzysztof Kozlowski
2021-09-08 7:47 ` Ard Biesheuvel
2021-09-08 7:50 ` Geert Uytterhoeven
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