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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
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10223c5286
Passing volatile-qualified pointers to the arm64 implementations of the load-acquire/store-release macros results in a re-load from the stack and a bunch of associated stack-protector churn due to the temporary result variable inheriting the volatile semantics thanks to the use of 'typeof()'. Define these temporary variables using 'unqual_scalar_typeof' to drop the volatile qualifier in the case that they are scalar types. Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Arnd Bergmann <arnd@arndb.de> Acked-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Will Deacon <will@kernel.org>
172 lines
4.2 KiB
C
172 lines
4.2 KiB
C
/* SPDX-License-Identifier: GPL-2.0-only */
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/*
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* Based on arch/arm/include/asm/barrier.h
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*
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* Copyright (C) 2012 ARM Ltd.
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*/
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#ifndef __ASM_BARRIER_H
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#define __ASM_BARRIER_H
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#ifndef __ASSEMBLY__
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#include <linux/kasan-checks.h>
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#define __nops(n) ".rept " #n "\nnop\n.endr\n"
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#define nops(n) asm volatile(__nops(n))
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#define sev() asm volatile("sev" : : : "memory")
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#define wfe() asm volatile("wfe" : : : "memory")
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#define wfi() asm volatile("wfi" : : : "memory")
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#define isb() asm volatile("isb" : : : "memory")
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#define dmb(opt) asm volatile("dmb " #opt : : : "memory")
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#define dsb(opt) asm volatile("dsb " #opt : : : "memory")
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#define psb_csync() asm volatile("hint #17" : : : "memory")
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#define csdb() asm volatile("hint #20" : : : "memory")
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#define spec_bar() asm volatile(ALTERNATIVE("dsb nsh\nisb\n", \
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SB_BARRIER_INSN"nop\n", \
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ARM64_HAS_SB))
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#ifdef CONFIG_ARM64_PSEUDO_NMI
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#define pmr_sync() \
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do { \
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extern struct static_key_false gic_pmr_sync; \
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\
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if (static_branch_unlikely(&gic_pmr_sync)) \
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dsb(sy); \
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} while(0)
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#else
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#define pmr_sync() do {} while (0)
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#endif
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#define mb() dsb(sy)
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#define rmb() dsb(ld)
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#define wmb() dsb(st)
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#define dma_rmb() dmb(oshld)
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#define dma_wmb() dmb(oshst)
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/*
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* Generate a mask for array_index__nospec() that is ~0UL when 0 <= idx < sz
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* and 0 otherwise.
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*/
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#define array_index_mask_nospec array_index_mask_nospec
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static inline unsigned long array_index_mask_nospec(unsigned long idx,
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unsigned long sz)
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{
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unsigned long mask;
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asm volatile(
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" cmp %1, %2\n"
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" sbc %0, xzr, xzr\n"
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: "=r" (mask)
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: "r" (idx), "Ir" (sz)
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: "cc");
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csdb();
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return mask;
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}
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#define __smp_mb() dmb(ish)
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#define __smp_rmb() dmb(ishld)
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#define __smp_wmb() dmb(ishst)
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#define __smp_store_release(p, v) \
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do { \
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typeof(p) __p = (p); \
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union { __unqual_scalar_typeof(*p) __val; char __c[1]; } __u = \
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{ .__val = (__force __unqual_scalar_typeof(*p)) (v) }; \
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compiletime_assert_atomic_type(*p); \
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kasan_check_write(__p, sizeof(*p)); \
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switch (sizeof(*p)) { \
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case 1: \
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asm volatile ("stlrb %w1, %0" \
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: "=Q" (*__p) \
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: "r" (*(__u8 *)__u.__c) \
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: "memory"); \
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break; \
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case 2: \
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asm volatile ("stlrh %w1, %0" \
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: "=Q" (*__p) \
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: "r" (*(__u16 *)__u.__c) \
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: "memory"); \
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break; \
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case 4: \
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asm volatile ("stlr %w1, %0" \
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: "=Q" (*__p) \
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: "r" (*(__u32 *)__u.__c) \
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: "memory"); \
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break; \
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case 8: \
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asm volatile ("stlr %1, %0" \
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: "=Q" (*__p) \
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: "r" (*(__u64 *)__u.__c) \
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: "memory"); \
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break; \
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} \
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} while (0)
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#define __smp_load_acquire(p) \
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({ \
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union { __unqual_scalar_typeof(*p) __val; char __c[1]; } __u; \
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typeof(p) __p = (p); \
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compiletime_assert_atomic_type(*p); \
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kasan_check_read(__p, sizeof(*p)); \
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switch (sizeof(*p)) { \
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case 1: \
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asm volatile ("ldarb %w0, %1" \
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: "=r" (*(__u8 *)__u.__c) \
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: "Q" (*__p) : "memory"); \
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break; \
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case 2: \
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asm volatile ("ldarh %w0, %1" \
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: "=r" (*(__u16 *)__u.__c) \
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: "Q" (*__p) : "memory"); \
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break; \
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case 4: \
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asm volatile ("ldar %w0, %1" \
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: "=r" (*(__u32 *)__u.__c) \
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: "Q" (*__p) : "memory"); \
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break; \
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case 8: \
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asm volatile ("ldar %0, %1" \
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: "=r" (*(__u64 *)__u.__c) \
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: "Q" (*__p) : "memory"); \
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break; \
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} \
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(typeof(*p))__u.__val; \
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})
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#define smp_cond_load_relaxed(ptr, cond_expr) \
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({ \
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typeof(ptr) __PTR = (ptr); \
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__unqual_scalar_typeof(*ptr) VAL; \
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for (;;) { \
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VAL = READ_ONCE(*__PTR); \
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if (cond_expr) \
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break; \
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__cmpwait_relaxed(__PTR, VAL); \
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} \
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(typeof(*ptr))VAL; \
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})
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#define smp_cond_load_acquire(ptr, cond_expr) \
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({ \
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typeof(ptr) __PTR = (ptr); \
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__unqual_scalar_typeof(*ptr) VAL; \
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for (;;) { \
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VAL = smp_load_acquire(__PTR); \
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if (cond_expr) \
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break; \
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__cmpwait_relaxed(__PTR, VAL); \
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} \
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(typeof(*ptr))VAL; \
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})
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#include <asm-generic/barrier.h>
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#endif /* __ASSEMBLY__ */
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#endif /* __ASM_BARRIER_H */
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