/* * 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; } e='0' selected='selected'>unified
authorArd Biesheuvel <ard.biesheuvel@linaro.org>2017-02-01 17:45:02 +0000
committerIngo Molnar <mingo@kernel.org>2017-02-01 21:17:49 +0100
commitc8f325a59cfc718d13a50fbc746ed9b415c25e92 (patch)
treed53fbdac9d0781e39a13b2ac6b2bd258cf3b4140 /include/trace/events/host1x.h
parentbf29bddf0417a4783da3b24e8c9e017ac649326f (diff)
efi/fdt: Avoid FDT manipulation after ExitBootServices()
Some AArch64 UEFI implementations disable the MMU in ExitBootServices(), after which unaligned accesses to RAM are no longer supported. Commit: abfb7b686a3e ("efi/libstub/arm*: Pass latest memory map to the kernel") fixed an issue in the memory map handling of the stub FDT code, but inadvertently created an issue with such firmware, by moving some of the FDT manipulation to after the invocation of ExitBootServices(). Given that the stub's libfdt implementation uses the ordinary, accelerated string functions, which rely on hardware handling of unaligned accesses, manipulating the FDT with the MMU off may result in alignment faults. So fix the situation by moving the update_fdt_memmap() call into the callback function invoked by efi_exit_boot_services() right before it calls the ExitBootServices() UEFI service (which is arguably a better place for it anyway) Note that disabling the MMU in ExitBootServices() is not compliant with the UEFI spec, and carries great risk due to the fact that switching from cached to uncached memory accesses halfway through compiler generated code (i.e., involving a stack) can never be done in a way that is architecturally safe. Fixes: abfb7b686a3e ("efi/libstub/arm*: Pass latest memory map to the kernel") Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Tested-by: Riku Voipio <riku.voipio@linaro.org> Cc: <stable@vger.kernel.org> Cc: mark.rutland@arm.com Cc: linux-efi@vger.kernel.org Cc: matt@codeblueprint.co.uk Cc: leif.lindholm@linaro.org Cc: linux-arm-kernel@lists.infradead.org Link: http://lkml.kernel.org/r/1485971102-23330-2-git-send-email-ard.biesheuvel@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'include/trace/events/host1x.h')