/* * Read/write thread of a guest agent for virtio-trace * * Copyright (C) 2012 Hitachi, Ltd. * Created by Yoshihiro Yunomae * Masami Hiramatsu * * Licensed under GPL version 2 only. * */ #define _GNU_SOURCE #include #include #include #include #include #include "trace-agent.h" #define READ_WAIT_USEC 100000 void *rw_thread_info_new(void) { struct rw_thread_info *rw_ti; rw_ti = zalloc(sizeof(struct rw_thread_info)); if (rw_ti == NULL) { pr_err("rw_thread_info zalloc error\n"); exit(EXIT_FAILURE); } rw_ti->cpu_num = -1; rw_ti->in_fd = -1; rw_ti->out_fd = -1; rw_ti->read_pipe = -1; rw_ti->write_pipe = -1; rw_ti->pipe_size = PIPE_INIT; return rw_ti; } void *rw_thread_init(int cpu, const char *in_path, const char *out_path, bool stdout_flag, unsigned long pipe_size, struct rw_thread_info *rw_ti) { int data_pipe[2]; rw_ti->cpu_num = cpu; /* set read(input) fd */ rw_ti->in_fd = open(in_path, O_RDONLY); if (rw_ti->in_fd == -1) { pr_err("Could not open in_fd (CPU:%d)\n", cpu); goto error; } /* set write(output) fd */ if (!stdout_flag) { /* virtio-serial output mode */ rw_ti->out_fd = open(out_path, O_WRONLY); if (rw_ti->out_fd == -1) { pr_err("Could not open out_fd (CPU:%d)\n", cpu); goto error; } } else /* stdout mode */ rw_ti->out_fd = STDOUT_FILENO; if (pipe2(data_pipe, O_NONBLOCK) < 0) { pr_err("Could not create pipe in rw-thread(%d)\n", cpu); goto error; } /* * Size of pipe is 64kB in default based on fs/pipe.c. * To read/write trace data speedy, pipe size is changed. */ if (fcntl(*data_pipe, F_SETPIPE_SZ, pipe_size) < 0) { pr_err("Could not change pipe size in rw-thread(%d)\n", cpu); goto error; } rw_ti->read_pipe = data_pipe[1]; rw_ti->write_pipe = data_pipe[0]; rw_ti->pipe_size = pipe_size; return NULL; error: exit(EXIT_FAILURE); } /* Bind a thread to a cpu */ static void bind_cpu(int cpu_num) { cpu_set_t mask; CPU_ZERO(&mask); CPU_SET(cpu_num, &mask); /* bind my thread to cpu_num by assigning zero to the first argument */ if (sched_setaffinity(0, sizeof(mask), &mask) == -1) pr_err("Could not set CPU#%d affinity\n", (int)cpu_num); } static void *rw_thread_main(void *thread_info) { ssize_t rlen, wlen; ssize_t ret; struct rw_thread_info *ts = (struct rw_thread_info *)thread_info; bind_cpu(ts->cpu_num); while (1) { /* Wait for a read order of trace data by Host OS */ if (!global_run_operation) { pthread_mutex_lock(&mutex_notify); pthread_cond_wait(&cond_wakeup, &mutex_notify); pthread_mutex_unlock(&mutex_notify); } if (global_sig_receive) break; /* * Each thread read trace_pipe_raw of each cpu bounding the * thread, so contention of multi-threads does not occur. */ rlen = splice(ts->in_fd, NULL, ts->read_pipe, NULL, ts->pipe_size, SPLICE_F_MOVE | SPLICE_F_MORE); if (rlen < 0) { pr_err("Splice_read in rw-thread(%d)\n", ts->cpu_num); goto error; } else if (rlen == 0) { /* * If trace data do not exist or are unreadable not * for exceeding the page size, splice_read returns * NULL. Then, this waits for being filled the data in a * ring-buffer. */ usleep(READ_WAIT_USEC); pr_debug("Read retry(cpu:%d)\n", ts->cpu_num); continue; } wlen = 0; do { ret = splice(ts->write_pipe, NULL, ts->out_fd, NULL, rlen - wlen, SPLICE_F_MOVE | SPLICE_F_MORE); if (ret < 0) { pr_err("Splice_write in rw-thread(%d)\n", ts->cpu_num); goto error; } else if (ret == 0) /* * When host reader is not in time for reading * trace data, guest will be stopped. This is * because char dev in QEMU is not supported * non-blocking mode. Then, writer might be * sleep in that case. * This sleep will be removed by supporting * non-blocking mode. */ sleep(1); wlen += ret; } while (wlen < rlen); } return NULL; error: exit(EXIT_FAILURE); } pthread_t rw_thread_run(struct rw_thread_info *rw_ti) { int ret; pthread_t rw_thread_per_cpu; ret = pthread_create(&rw_thread_per_cpu, NULL, rw_thread_main, rw_ti); if (ret != 0) { pr_err("Could not create a rw thread(%d)\n", rw_ti->cpu_num); exit(EXIT_FAILURE); } return rw_thread_per_cpu; } s='label'>space:mode:
authorBenjamin Herrenschmidt <benh@kernel.crashing.org>2017-02-03 17:10:28 +1100
committerMichael Ellerman <mpe@ellerman.id.au>2017-02-08 23:36:29 +1100
commitd7df2443cd5f67fc6ee7c05a88e4996e8177f91b (patch)
tree098a7c0ca4fceb8a65cb1f693c9d71990388933d /net/nfc/nci/Kconfig
parenta0615a16f7d0ceb5804d295203c302d496d8ee91 (diff)
powerpc/mm: Fix spurrious segfaults on radix with autonuma
When autonuma (Automatic NUMA balancing) marks a PTE inaccessible it clears all the protection bits but leave the PTE valid. With the Radix MMU, an attempt at executing from such a PTE will take a fault with bit 35 of SRR1 set "SRR1_ISI_N_OR_G". It is thus incorrect to treat all such faults as errors. We should pass them to handle_mm_fault() for autonuma to deal with. The case of pages that are really not executable is handled by the existing test for VM_EXEC further down. That leaves us with catching the kernel attempts at executing user pages. We can catch that earlier, even before we do find_vma. It is never valid on powerpc for the kernel to take an exec fault to begin with. So fold that test with the existing test for the kernel faulting on kernel addresses to bail out early. Fixes: 1d18ad026844 ("powerpc/mm: Detect instruction fetch denied and report") Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Acked-by: Balbir Singh <bsingharora@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'net/nfc/nci/Kconfig')