// SPDX-License-Identifier: GPL-2.0
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#include <errno.h>
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#include <linux/compiler.h>
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#include <linux/perf_event.h>
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#include <linux/stddef.h>
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#include <linux/types.h>
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#include <asm/barrier.h>
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#include "event.h"
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#include "synthetic-events.h"
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#include "debug.h"
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#include "tsc.h"
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u64 perf_time_to_tsc(u64 ns, struct perf_tsc_conversion *tc)
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{
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u64 t, quot, rem;
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t = ns - tc->time_zero;
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quot = t / tc->time_mult;
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rem = t % tc->time_mult;
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return (quot << tc->time_shift) +
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(rem << tc->time_shift) / tc->time_mult;
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}
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u64 tsc_to_perf_time(u64 cyc, struct perf_tsc_conversion *tc)
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{
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u64 quot, rem;
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if (tc->cap_user_time_short)
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cyc = tc->time_cycles +
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((cyc - tc->time_cycles) & tc->time_mask);
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quot = cyc >> tc->time_shift;
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rem = cyc & (((u64)1 << tc->time_shift) - 1);
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return tc->time_zero + quot * tc->time_mult +
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((rem * tc->time_mult) >> tc->time_shift);
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}
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int perf_read_tsc_conversion(const struct perf_event_mmap_page *pc,
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struct perf_tsc_conversion *tc)
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{
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u32 seq;
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int i = 0;
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while (1) {
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seq = pc->lock;
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rmb();
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tc->time_mult = pc->time_mult;
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tc->time_shift = pc->time_shift;
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tc->time_zero = pc->time_zero;
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tc->time_cycles = pc->time_cycles;
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tc->time_mask = pc->time_mask;
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tc->cap_user_time_zero = pc->cap_user_time_zero;
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tc->cap_user_time_short = pc->cap_user_time_short;
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rmb();
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if (pc->lock == seq && !(seq & 1))
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break;
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if (++i > 10000) {
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pr_debug("failed to get perf_event_mmap_page lock\n");
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return -EINVAL;
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}
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}
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if (!tc->cap_user_time_zero)
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return -EOPNOTSUPP;
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return 0;
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}
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int perf_event__synth_time_conv(const struct perf_event_mmap_page *pc,
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struct perf_tool *tool,
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perf_event__handler_t process,
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struct machine *machine)
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{
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union perf_event event = {
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.time_conv = {
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.header = {
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.type = PERF_RECORD_TIME_CONV,
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.size = sizeof(struct perf_record_time_conv),
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},
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},
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};
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struct perf_tsc_conversion tc;
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int err;
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if (!pc)
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return 0;
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err = perf_read_tsc_conversion(pc, &tc);
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if (err == -EOPNOTSUPP)
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return 0;
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if (err)
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return err;
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pr_debug2("Synthesizing TSC conversion information\n");
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event.time_conv.time_mult = tc.time_mult;
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event.time_conv.time_shift = tc.time_shift;
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event.time_conv.time_zero = tc.time_zero;
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event.time_conv.time_cycles = tc.time_cycles;
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event.time_conv.time_mask = tc.time_mask;
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event.time_conv.cap_user_time_zero = tc.cap_user_time_zero;
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event.time_conv.cap_user_time_short = tc.cap_user_time_short;
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return process(tool, &event, NULL, machine);
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}
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u64 __weak rdtsc(void)
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{
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return 0;
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}
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