Method add

KittyMemoryEx/KittyPerfEvent.cpp:3–61

#include "KittyPerfEvent.hpp"

bool KittyPerfWatch::add(pid_t tid, uintptr_t addr, KT_WATCH_TYPE bp_type, KT_WATCH_LEN bp_len)
{
#if defined(__arm__) || defined(__aarch64__)
    addr &= ~3UL;
#endif

    perf_event_attr pe{};
    pe.type = PERF_TYPE_BREAKPOINT;
    pe.config = 0;
    pe.size = sizeof(pe);

    pe.bp_addr = addr;
    pe.bp_len = bp_len;
    pe.bp_type = bp_type;

    pe.sample_period = 1;
    pe.sample_type = PERF_SAMPLE_IP | PERF_SAMPLE_TID | PERF_SAMPLE_TIME | PERF_SAMPLE_ADDR;

    pe.exclude_kernel = 1;
    pe.exclude_hv = 1;
    pe.disabled = 1;
    pe.wakeup_events = 1;
    pe.precise_ip = 2;

    int fd = perf_event_open(&pe, tid, -1, -1, 0);
    if (fd < 0)
        return false;

    size_t page_sz = sysconf(_SC_PAGESIZE);
    size_t mmap_sz = (1 + KT_WATCH_PAGES) * page_sz;

    void *base = mmap(nullptr, mmap_sz, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
    if (!base || base == MAP_FAILED)
    {
        ioctl(fd, PERF_EVENT_IOC_RESET, 0);
        ioctl(fd, PERF_EVENT_IOC_DISABLE, 0);
        close(fd);
        return false;
    }

    auto *meta = reinterpret_cast<perf_event_mmap_page *>(base);
    if (meta->data_size == 0)
    {
        ioctl(fd, PERF_EVENT_IOC_RESET, 0);
        ioctl(fd, PERF_EVENT_IOC_DISABLE, 0);
        munmap(base, mmap_sz);
        close(fd);
        return false;
    }

    WatchInfo w{};
    w.fd = fd;
    w.mmap = base;
    w.mmap_sz = mmap_sz;

    _watches.push_back(w);

    return true;