#define _GNU_SOURCE #include #include #include #include #include #include #include #include #include #include #include "cgroup_helpers.h" /* * To avoid relying on the system setup, when setup_cgroup_env is called * we create a new mount namespace, and cgroup namespace. The cgroup2 * root is mounted at CGROUP_MOUNT_PATH * * Unfortunately, most people don't have cgroupv2 enabled at this point in time. * It's easier to create our own mount namespace and manage it ourselves. * * We assume /mnt exists. */ #define WALK_FD_LIMIT 16 #define CGROUP_MOUNT_PATH "/mnt" #define CGROUP_WORK_DIR "/cgroup-test-work-dir" #define format_cgroup_path(buf, path) \ snprintf(buf, sizeof(buf), "%s%s%s", CGROUP_MOUNT_PATH, \ CGROUP_WORK_DIR, path) /** * setup_cgroup_environment() - Setup the cgroup environment * * After calling this function, cleanup_cgroup_environment should be called * once testing is complete. * * This function will print an error to stderr and return 1 if it is unable * to setup the cgroup environment. If setup is successful, 0 is returned. */ int setup_cgroup_environment(void) { char cgroup_workdir[PATH_MAX + 1]; format_cgroup_path(cgroup_workdir, ""); if (unshare(CLONE_NEWNS)) { log_err("unshare"); return 1; } if (mount("none", "/", NULL, MS_REC | MS_PRIVATE, NULL)) { log_err("mount fakeroot"); return 1; } if (mount("none", CGROUP_MOUNT_PATH, "cgroup2", 0, NULL)) { log_err("mount cgroup2"); return 1; } /* Cleanup existing failed runs, now that the environment is setup */ cleanup_cgroup_environment(); if (mkdir(cgroup_workdir, 0777) && errno != EEXIST) { log_err("mkdir cgroup work dir"); return 1; } return 0; } static int nftwfunc(const char *filename, const struct stat *statptr, int fileflags, struct FTW *pfwt) { if ((fileflags & FTW_D) && rmdir(filename)) log_err("Removing cgroup: %s", filename); return 0; } static int join_cgroup_from_top(char *cgroup_path) { char cgroup_procs_path[PATH_MAX + 1]; pid_t pid = getpid(); int fd, rc = 0; snprintf(cgroup_procs_path, sizeof(cgroup_procs_path), "%s/cgroup.procs", cgroup_path); fd = open(cgroup_procs_path, O_WRONLY); if (fd < 0) { log_err("Opening Cgroup Procs: %s", cgroup_procs_path); return 1; } if (dprintf(fd, "%d\n", pid) < 0) { log_err("Joining Cgroup"); rc = 1; } close(fd); return rc; } /** * join_cgroup() - Join a cgroup * @path: The cgroup path, relative to the workdir, to join * * This function expects a cgroup to already be created, relative to the cgroup * work dir, and it joins it. For example, passing "/my-cgroup" as the path * would actually put the calling process into the cgroup * "/cgroup-test-work-dir/my-cgroup" * * On success, it returns 0, otherwise on failure it returns 1. */ int join_cgroup(char *path) { char cgroup_path[PATH_MAX + 1]; format_cgroup_path(cgroup_path, path); return join_cgroup_from_top(cgroup_path); } /** * cleanup_cgroup_environment() - Cleanup Cgroup Testing Environment * * This is an idempotent function to delete all temporary cgroups that * have been created during the test, including the cgroup testing work * directory. * * At call time, it moves the calling process to the root cgroup, and then * runs the deletion process. It is idempotent, and should not fail, unless * a process is lingering. * * On failure, it will print an error to stderr, and try to continue. */ void cleanup_cgroup_environment(void) { char cgroup_workdir[PATH_MAX + 1]; format_cgroup_path(cgroup_workdir, ""); join_cgroup_from_top(CGROUP_MOUNT_PATH); nftw(cgroup_workdir, nftwfunc, WALK_FD_LIMIT, FTW_DEPTH | FTW_MOUNT); } /** * create_and_get_cgroup() - Create a cgroup, relative to workdir, and get the FD * @path: The cgroup path, relative to the workdir, to join * * This function creates a cgroup under the top level workdir and returns the * file descriptor. It is idempotent. * * On success, it returns the file descriptor. On failure it returns 0. * If there is a failure, it prints the error to stderr. */ int create_and_get_cgroup(char *path) { char cgroup_path[PATH_MAX + 1]; int fd; format_cgroup_path(cgroup_path, path); if (mkdir(cgroup_path, 0777) && errno != EEXIST) { log_err("mkdiring cgroup"); return 0; } fd = open(cgroup_path, O_RDONLY); if (fd < 0) { log_err("Opening Cgroup"); return 0; } return fd; } t only
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 /sound/soc/blackfin/bf6xx-i2s.c
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 'sound/soc/blackfin/bf6xx-i2s.c')