/* * POWER Data Stream Control Register (DSCR) fork test * * This testcase modifies the DSCR using mtspr, forks and then * verifies that the child process has the correct changed DSCR * value using mfspr. * * When using the privilege state SPR, the instructions such as * mfspr or mtspr are priviledged and the kernel emulates them * for us. Instructions using problem state SPR can be exuecuted * directly without any emulation if the HW supports them. Else * they also get emulated by the kernel. * * Copyright 2012, Anton Blanchard, IBM Corporation. * Copyright 2015, Anshuman Khandual, IBM Corporation. * * This program is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 as published * by the Free Software Foundation. */ #include "dscr.h" int dscr_inherit(void) { unsigned long i, dscr = 0; pid_t pid; srand(getpid()); set_dscr(dscr); for (i = 0; i < COUNT; i++) { unsigned long cur_dscr, cur_dscr_usr; dscr++; if (dscr > DSCR_MAX) dscr = 0; if (i % 2 == 0) set_dscr_usr(dscr); else set_dscr(dscr); pid = fork(); if (pid == -1) { perror("fork() failed"); exit(1); } else if (pid) { int status; if (waitpid(pid, &status, 0) == -1) { perror("waitpid() failed"); exit(1); } if (!WIFEXITED(status)) { fprintf(stderr, "Child didn't exit cleanly\n"); exit(1); } if (WEXITSTATUS(status) != 0) { fprintf(stderr, "Child didn't exit cleanly\n"); return 1; } } else { cur_dscr = get_dscr(); if (cur_dscr != dscr) { fprintf(stderr, "Kernel DSCR should be %ld " "but is %ld\n", dscr, cur_dscr); exit(1); } cur_dscr_usr = get_dscr_usr(); if (cur_dscr_usr != dscr) { fprintf(stderr, "User DSCR should be %ld " "but is %ld\n", dscr, cur_dscr_usr); exit(1); } exit(0); } } return 0; } int main(int argc, char *argv[]) { return test_harness(dscr_inherit, "dscr_inherit_test"); } 68d'>treecommitdiff
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authorLinus Torvalds <torvalds@linux-foundation.org>2017-01-24 12:21:51 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2017-01-24 12:21:51 -0800
commit19ca2c8fecb1592d623fe5e82d6796f8d446268d (patch)
tree0756e115d125846f46b302085307768f069434a1 /include/acpi/acpi_io.h
parenta4685d2f58e2230d4e27fb2ee581d7ea35e5d046 (diff)
parent880a38547ff08715ce4f1daf9a4bb30c87676e68 (diff)
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace
Pull namespace fix from Eric Biederman: "This has a single brown bag fix. The possible deadlock with dec_pid_namespaces that I had thought was fixed earlier turned out only to have been moved. So instead of being cleaver this change takes ucounts_lock with irqs disabled. So dec_ucount can be used from any context without fear of deadlock. The items accounted for dec_ucount and inc_ucount are all comparatively heavy weight objects so I don't exepct this will have any measurable performance impact" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: userns: Make ucounts lock irq-safe
Diffstat (limited to 'include/acpi/acpi_io.h')