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| 1 | /* SPDX-License-Identifier: GPL-2.0-only */ |
|---|---|
| 2 | /* |
| 3 | * Copyright 2012 Calxeda, Inc. |
| 4 | */ |
| 5 | #ifndef _ASM_ARM_PERCPU_H_ |
| 6 | #define _ASM_ARM_PERCPU_H_ |
| 7 | |
| 8 | #include <asm/insn.h> |
| 9 | |
| 10 | register unsigned long current_stack_pointer asm ("sp"); |
| 11 | |
| 12 | /* |
| 13 | * Same as asm-generic/percpu.h, except that we store the per cpu offset |
| 14 | * in the TPIDRPRW. TPIDRPRW only exists on V6K and V7 |
| 15 | */ |
| 16 | #ifdef CONFIG_SMP |
| 17 | static inline void set_my_cpu_offset(unsigned long off) |
| 18 | { |
| 19 | extern unsigned int smp_on_up; |
| 20 | |
| 21 | if (IS_ENABLED(CONFIG_CPU_V6) && !smp_on_up) |
| 22 | return; |
| 23 | |
| 24 | /* Set TPIDRPRW */ |
| 25 | asm volatile("mcr p15, 0, %0, c13, c0, 4" : : "r" (off) : "memory"); |
| 26 | } |
| 27 | |
| 28 | static __always_inline unsigned long __my_cpu_offset(void) |
| 29 | { |
| 30 | unsigned long off; |
| 31 | |
| 32 | /* |
| 33 | * Read TPIDRPRW. |
| 34 | * We want to allow caching the value, so avoid using volatile and |
| 35 | * instead use a fake stack read to hazard against barrier(). |
| 36 | */ |
| 37 | asm("0: mrc p15, 0, %0, c13, c0, 4 \n\t" |
| 38 | #ifdef CONFIG_CPU_V6 |
| 39 | "1: \n\t" |
| 40 | " .subsection 1 \n\t" |
| 41 | #if defined(CONFIG_ARM_HAS_GROUP_RELOCS) && \ |
| 42 | !(defined(MODULE) && defined(CONFIG_ARM_MODULE_PLTS)) |
| 43 | "2: " LOAD_SYM_ARMV6(%0, __per_cpu_offset) " \n\t" |
| 44 | " b 1b \n\t" |
| 45 | #else |
| 46 | "2: ldr %0, 3f \n\t" |
| 47 | " ldr %0, [%0] \n\t" |
| 48 | " b 1b \n\t" |
| 49 | "3: .long __per_cpu_offset \n\t" |
| 50 | #endif |
| 51 | " .previous \n\t" |
| 52 | " .pushsection \".alt.smp.init\", \"a\" \n\t" |
| 53 | " .long 0b - . \n\t" |
| 54 | " b . + (2b - 0b) \n\t" |
| 55 | " .popsection \n\t" |
| 56 | #endif |
| 57 | : "=r" (off) |
| 58 | : "Q" (*(const unsigned long *)current_stack_pointer)); |
| 59 | |
| 60 | return off; |
| 61 | } |
| 62 | #define __my_cpu_offset __my_cpu_offset() |
| 63 | #else |
| 64 | #define set_my_cpu_offset(x) do {} while(0) |
| 65 | |
| 66 | #endif /* CONFIG_SMP */ |
| 67 | |
| 68 | #include <asm-generic/percpu.h> |
| 69 | |
| 70 | #endif /* _ASM_ARM_PERCPU_H_ */ |
| 71 |
Warning: This file is not a C or C++ file. It does not have highlighting.