4a1d47ebea
spdk_compiler_barrier() prevents the compiler from moving pointer dereferences across the barrier. Use this in the MMIO helper functions to ensure that the compiler can't reorder operations around e.g. hardware register access. Specifically, this fixes the compiler optimizing out writes to g_thread_mmio_ctrlr in the NVMe hotplug handling code. Change-Id: I6b9cec48da0e6d8d75825c28b12ece5251110080 Signed-off-by: Daniel Verkamp <daniel.verkamp@intel.com>
112 lines
2.9 KiB
C
112 lines
2.9 KiB
C
/*-
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* BSD LICENSE
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*
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* Copyright (c) Intel Corporation.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* * Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* * Neither the name of Intel Corporation nor the names of its
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* contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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/** \file
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* Memory-mapped I/O utility functions
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*/
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#ifndef SPDK_MMIO_H
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#define SPDK_MMIO_H
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#ifdef __cplusplus
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extern "C" {
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#endif
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#include <inttypes.h>
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#include "spdk/barrier.h"
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#ifdef __x86_64__
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#define SPDK_MMIO_64BIT 1 /* Can do atomic 64-bit memory read/write (over PCIe) */
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#else
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#define SPDK_MMIO_64BIT 0
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#endif
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static inline uint32_t
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spdk_mmio_read_4(const volatile uint32_t *addr)
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{
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spdk_compiler_barrier();
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return *addr;
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}
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static inline void
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spdk_mmio_write_4(volatile uint32_t *addr, uint32_t val)
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{
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spdk_compiler_barrier();
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*addr = val;
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}
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static inline uint64_t
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spdk_mmio_read_8(volatile uint64_t *addr)
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{
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uint64_t val;
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volatile uint32_t *addr32 = (volatile uint32_t *)addr;
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spdk_compiler_barrier();
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if (SPDK_MMIO_64BIT) {
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val = *addr;
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} else {
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/*
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* Read lower 4 bytes before upper 4 bytes.
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* This particular order is required by I/OAT.
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* If the other order is required, use a pair of spdk_mmio_read_4() calls.
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*/
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val = addr32[0];
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val |= (uint64_t)addr32[1] << 32;
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}
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return val;
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}
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static inline void
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spdk_mmio_write_8(volatile uint64_t *addr, uint64_t val)
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{
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volatile uint32_t *addr32 = (volatile uint32_t *)addr;
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spdk_compiler_barrier();
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if (SPDK_MMIO_64BIT) {
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*addr = val;
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} else {
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addr32[0] = (uint32_t)val;
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addr32[1] = (uint32_t)(val >> 32);
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}
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}
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#ifdef __cplusplus
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}
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#endif
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#endif
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