#include #include "util.h" #include "../perf.h" #include "cloexec.h" #include "asm/bug.h" #include "debug.h" #include #include #include static unsigned long flag = PERF_FLAG_FD_CLOEXEC; int __weak sched_getcpu(void) { #ifdef __NR_getcpu unsigned cpu; int err = syscall(__NR_getcpu, &cpu, NULL, NULL); if (!err) return cpu; #else errno = ENOSYS; #endif return -1; } static int perf_flag_probe(void) { /* use 'safest' configuration as used in perf_evsel__fallback() */ struct perf_event_attr attr = { .type = PERF_TYPE_SOFTWARE, .config = PERF_COUNT_SW_CPU_CLOCK, .exclude_kernel = 1, }; int fd; int err; int cpu; pid_t pid = -1; char sbuf[STRERR_BUFSIZE]; cpu = sched_getcpu(); if (cpu < 0) cpu = 0; /* * Using -1 for the pid is a workaround to avoid gratuitous jump label * changes. */ while (1) { /* check cloexec flag */ fd = sys_perf_event_open(&attr, pid, cpu, -1, PERF_FLAG_FD_CLOEXEC); if (fd < 0 && pid == -1 && errno == EACCES) { pid = 0; continue; } break; } err = errno; if (fd >= 0) { close(fd); return 1; } WARN_ONCE(err != EINVAL && err != EBUSY, "perf_event_open(..., PERF_FLAG_FD_CLOEXEC) failed with unexpected error %d (%s)\n", err, str_error_r(err, sbuf, sizeof(sbuf))); /* not supported, confirm error related to PERF_FLAG_FD_CLOEXEC */ while (1) { fd = sys_perf_event_open(&attr, pid, cpu, -1, 0); if (fd < 0 && pid == -1 && errno == EACCES) { pid = 0; continue; } break; } err = errno; if (fd >= 0) close(fd); if (WARN_ONCE(fd < 0 && err != EBUSY, "perf_event_open(..., 0) failed unexpectedly with error %d (%s)\n", err, str_error_r(err, sbuf, sizeof(sbuf)))) return -1; return 0; } unsigned long perf_event_open_cloexec_flag(void) { static bool probed; if (!probed) { if (perf_flag_probe() <= 0) flag = 0; probed = true; } return flag; } ctive' href='/cgit.cgi/linux/net-next.git/commit/sound/pci/echoaudio/indigodj_dsp.c?id=d7df2443cd5f67fc6ee7c05a88e4996e8177f91b'>commitdiff
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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 /sound/pci/echoaudio/indigodj_dsp.c
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 'sound/pci/echoaudio/indigodj_dsp.c')