From: Keith Packard <keithpac@amazon.com> To: linux-kernel@vger.kernel.org Cc: "Abbott Liu" <liuwenliang@huawei.com>, "Alexei Starovoitov" <ast@kernel.org>, "Andrew Morton" <akpm@linux-foundation.org>, "Andrii Nakryiko" <andrii@kernel.org>, "Anshuman Khandual" <anshuman.khandual@arm.com>, "Ard Biesheuvel" <ardb@kernel.org>, "Arnd Bergmann" <arnd@arndb.de>, "Ben Segall" <bsegall@google.com>, "Bjorn Andersson" <bjorn.andersson@linaro.org>, bpf@vger.kernel.org, "Christoph Lameter" <cl@linux.com>, "Daniel Borkmann" <daniel@iogearbox.net>, "Daniel Bristot de Oliveira" <bristot@redhat.com>, "Dennis Zhou" <dennis@kernel.org>, devicetree@vger.kernel.org, "Dietmar Eggemann" <dietmar.eggemann@arm.com>, "Florian Fainelli" <f.fainelli@gmail.com>, "Frank Rowand" <frowand.list@gmail.com>, "Geert Uytterhoeven" <geert+renesas@glider.be>, "Ingo Molnar" <mingo@redhat.com>, "Jason Wang" <jasowang@redhat.com>, "Jens Axboe" <axboe@kernel.dk>, "Joe Perches" <joe@perches.com>, "John Fastabend" <john.fastabend@gmail.com>, "Juri Lelli" <juri.lelli@redhat.com>, "Keith Packard" <keithpac@amazon.com>, "KP Singh" <kpsingh@kernel.org>, kvm@vger.kernel.org, "Linus Walleij" <linus.walleij@linaro.org>, linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, "Manivannan Sadhasivam" <mani@kernel.org>, "Marc Zyngier" <maz@kernel.org>, "Martin KaFai Lau" <kafai@fb.com>, "Mel Gorman" <mgorman@suse.de>, "Michael Ellerman" <mpe@ellerman.id.au>, "Michael S. Tsirkin" <mst@redhat.com>, "Miguel Ojeda" <ojeda@kernel.org>, "Mike Rapoport" <rppt@kernel.org>, netdev@vger.kernel.org, "Nick Desaulniers" <ndesaulniers@google.com>, "Nick Desaulniers" <ndesaulniers@gooogle.com>, "Nicolas Pitre" <nico@fluxnic.net>, "Peter Zijlstra" <peterz@infradead.org>, "Rob Herring" <robh+dt@kernel.org>, "Russell King" <linux@armlinux.org.uk>, "Song Liu" <songliubraving@fb.com>, "Srikar Dronamraju" <srikar@linux.vnet.ibm.com>, "Steven Rostedt" <rostedt@goodmis.org>, "Tejun Heo" <tj@kernel.org>, "Thomas Gleixner" <tglx@linutronix.de>, "Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>, "Valentin Schneider" <valentin.schneider@arm.com>, "Vincent Guittot" <vincent.guittot@linaro.org>, virtualization@lists.linux-foundation.org, "Wolfram Sang (Renesas)" <wsa+renesas@sang-engineering.com>, "YiFei Zhu" <yifeifz2@illinois.edu>, "Yonghong Song" <yhs@fb.com> Subject: [PATCH v4 5/7] ARM: Stop using TPIDRPRW to hold per_cpu_offset Date: Wed, 8 Sep 2021 12:06:03 -0700 [thread overview] Message-ID: <20210908190605.419064-6-keithpac@amazon.com> (raw) In-Reply-To: <20210908190605.419064-1-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:[~2021-09-08 19:13 UTC|newest] Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top [not found] <id:20210907220038.91021-1-keithpac@amazon.com> 2021-09-08 19:05 ` [PATCH v4 0/7] ARM: support THREAD_INFO_IN_TASK Keith Packard 2021-09-08 19:05 ` [PATCH v4 1/7] ARM: Pass cpu number to secondary_start_kernel Keith Packard 2021-09-08 19:06 ` [PATCH v4 2/7] ARM: Pass task " Keith Packard 2021-09-08 19:06 ` [PATCH v4 3/7] ARM: Use smp_processor_id() in vfp_pm_suspend instead of ti->cpu Keith Packard 2021-09-08 19:06 ` [PATCH v4 4/7] Make sure task_struct is available for raw_smp_processor_id Keith Packard 2021-09-10 20:20 ` Rob Herring 2021-09-08 19:06 ` Keith Packard [this message] 2021-09-08 19:06 ` [PATCH v4 6/7] ARM: Use TPIDRPRW for current Keith Packard 2021-09-08 19:06 ` [PATCH v4 7/7] ARM: Move thread_info into task_struct (v7 only) Keith Packard
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