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coverage: introduce support for llvm profiling
Introduce the functionality in order to fill the hooks of the cov_sysctl_ops struct. Note that the functionality is still not wired into the build system. Signed-off-by: Roger Pau Monné <roger.pau@citrix.com> Acked-by: Jan Beulich <jbeulich@suse.com>
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Roger Pau Monné authored and 
Jan Beulich committed
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@@ -6,4 +6,6 @@ obj-y += $(call cc-ifversion,lt,0x040700, \
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gcc_4_7.o, $(call cc-ifversion,lt,0x050000, \
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gcc_4_9.o, $(call cc-ifversion,lt,0x070000, \
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gcc_5.o, gcc_7.o))))
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else
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obj-y += llvm.o
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endif
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@@ -0,0 +1,154 @@
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/*
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* Copyright (C) 2017 Citrix Systems R&D
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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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* 1. 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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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <xen/errno.h>
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#include <xen/guest_access.h>
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#include <xen/types.h>
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#include "coverage.h"
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#ifndef __clang__
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#error "LLVM coverage selected without clang compiler"
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#endif
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#if BITS_PER_LONG == 64
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#define LLVM_PROFILE_MAGIC (((uint64_t)255 << 56) | ((uint64_t)'l' << 48) | \
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((uint64_t)'p' << 40) | ((uint64_t)'r' << 32) | ((uint64_t)'o' << 24) | \
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((uint64_t)'f' << 16) | ((uint64_t)'r' << 8) | ((uint64_t)129))
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#else
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#define LLVM_PROFILE_MAGIC (((uint64_t)255 << 56) | ((uint64_t)'l' << 48) | \
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((uint64_t)'p' << 40) | ((uint64_t)'r' << 32) | ((uint64_t)'o' << 24) | \
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((uint64_t)'f' << 16) | ((uint64_t)'R' << 8) | ((uint64_t)129)
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#endif
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#if __clang_major__ >= 4 || (__clang_major__ == 3 && __clang_minor__ >= 9)
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#define LLVM_PROFILE_VERSION 4
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#define LLVM_PROFILE_NUM_KINDS 2
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#else
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#error "clang version not supported with coverage"
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#endif
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struct llvm_profile_data {
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uint64_t name_ref;
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uint64_t function_hash;
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void *counter;
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void *function;
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void *values;
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uint32_t nr_counters;
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uint16_t nr_value_sites[LLVM_PROFILE_NUM_KINDS];
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};
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struct llvm_profile_header {
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uint64_t magic;
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uint64_t version;
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uint64_t data_size;
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uint64_t counters_size;
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uint64_t names_size;
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uint64_t counters_delta;
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uint64_t names_delta;
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uint64_t value_kind_last;
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};
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/*
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* Since Xen uses the llvm code coverage support without the run time library
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* __llvm_profile_runtime must be defined according to the docs at:
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*
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* https://clang.llvm.org/docs/SourceBasedCodeCoverage.html
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*/
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int __llvm_profile_runtime;
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extern const struct llvm_profile_data __start___llvm_prf_data[];
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extern const struct llvm_profile_data __stop___llvm_prf_data[];
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extern const char __start___llvm_prf_names[];
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extern const char __stop___llvm_prf_names[];
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extern uint64_t __start___llvm_prf_cnts[];
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extern uint64_t __stop___llvm_prf_cnts[];
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#define START_DATA ((const void *)__start___llvm_prf_data)
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#define END_DATA ((const void *)__stop___llvm_prf_data)
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#define START_NAMES ((const void *)__start___llvm_prf_names)
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#define END_NAMES ((const void *)__stop___llvm_prf_names)
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#define START_COUNTERS ((void *)__start___llvm_prf_cnts)
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#define END_COUNTERS ((void *)__stop___llvm_prf_cnts)
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static void reset_counters(void)
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{
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memset(START_COUNTERS, 0, END_COUNTERS - START_COUNTERS);
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}
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static uint32_t get_size(void)
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{
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return ROUNDUP(sizeof(struct llvm_profile_header) + END_DATA - START_DATA +
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END_COUNTERS - START_COUNTERS + END_NAMES - START_NAMES, 8);
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}
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static int dump(XEN_GUEST_HANDLE_PARAM(char) buffer, uint32_t *buf_size)
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{
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struct llvm_profile_header header = {
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.magic = LLVM_PROFILE_MAGIC,
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.version = LLVM_PROFILE_VERSION,
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.data_size = (END_DATA - START_DATA) / sizeof(struct llvm_profile_data),
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.counters_size = (END_COUNTERS - START_COUNTERS) / sizeof(uint64_t),
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.names_size = END_NAMES - START_NAMES,
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.counters_delta = (uintptr_t)START_COUNTERS,
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.names_delta = (uintptr_t)START_NAMES,
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.value_kind_last = LLVM_PROFILE_NUM_KINDS - 1,
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};
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unsigned int off = 0;
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#define APPEND_TO_BUFFER(src, size) \
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({ \
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if ( off + (size) > *buf_size ) \
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return -ENOMEM; \
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copy_to_guest_offset(buffer, off, (const char *)src, size); \
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off += (size); \
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})
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APPEND_TO_BUFFER(&header, sizeof(header));
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APPEND_TO_BUFFER(START_DATA, END_DATA - START_DATA);
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APPEND_TO_BUFFER(START_COUNTERS, END_COUNTERS - START_COUNTERS);
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APPEND_TO_BUFFER(START_NAMES, END_NAMES - START_NAMES);
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#undef APPEND_TO_BUFFER
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clear_guest_offset(buffer, off, *buf_size - off);
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return 0;
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}
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const struct cov_sysctl_ops cov_ops = {
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.get_size = get_size,
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.reset_counters = reset_counters,
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.dump = dump,
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};
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/*
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* Local variables:
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* mode: C
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* c-file-style: "BSD"
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* c-basic-offset: 4
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* tab-width: 4
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* indent-tabs-mode: nil
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* End:
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*/
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@@ -646,6 +646,12 @@ struct xen_sysctl_scheduler_op {
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#define XEN_GCOV_FORMAT_MAGIC 0x58434f56 /* XCOV */
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/*
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* Ouput format of LLVM coverage data is just a raw stream, as would be
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* written by the compiler_rt run time library into a .profraw file. There
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* are no special Xen tags or delimiters because none are needed.
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*/
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#define XEN_SYSCTL_COVERAGE_get_size 0 /* Get total size of output data */
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#define XEN_SYSCTL_COVERAGE_read 1 /* Read output data */
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#define XEN_SYSCTL_COVERAGE_reset 2 /* Reset all counters */
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