diff options
Diffstat (limited to 'arch/arm/include/asm/percpu.h')
-rw-r--r-- | arch/arm/include/asm/percpu.h | 70 |
1 files changed, 70 insertions, 0 deletions
diff --git a/arch/arm/include/asm/percpu.h b/arch/arm/include/asm/percpu.h new file mode 100644 index 0000000000..7545c87c25 --- /dev/null +++ b/arch/arm/include/asm/percpu.h @@ -0,0 +1,70 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Copyright 2012 Calxeda, Inc. + */ +#ifndef _ASM_ARM_PERCPU_H_ +#define _ASM_ARM_PERCPU_H_ + +#include <asm/insn.h> + +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 + */ +#ifdef CONFIG_SMP +static inline void set_my_cpu_offset(unsigned long off) +{ + extern unsigned int smp_on_up; + + if (IS_ENABLED(CONFIG_CPU_V6) && !smp_on_up) + return; + + /* Set TPIDRPRW */ + asm volatile("mcr p15, 0, %0, c13, c0, 4" : : "r" (off) : "memory"); +} + +static __always_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("0: mrc p15, 0, %0, c13, c0, 4 \n\t" +#ifdef CONFIG_CPU_V6 + "1: \n\t" + " .subsection 1 \n\t" +#if defined(CONFIG_ARM_HAS_GROUP_RELOCS) && \ + !(defined(MODULE) && defined(CONFIG_ARM_MODULE_PLTS)) + "2: " LOAD_SYM_ARMV6(%0, __per_cpu_offset) " \n\t" + " b 1b \n\t" +#else + "2: ldr %0, 3f \n\t" + " ldr %0, [%0] \n\t" + " b 1b \n\t" + "3: .long __per_cpu_offset \n\t" +#endif + " .previous \n\t" + " .pushsection \".alt.smp.init\", \"a\" \n\t" + " .long 0b - . \n\t" + " b . + (2b - 0b) \n\t" + " .popsection \n\t" +#endif + : "=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_ */ |