powerpc/mm/stack_expansion_signal.c

0001 // SPDX-License-Identifier: GPL-2.0
0002 /*
0003  * Test that signal delivery is able to expand the stack segment without
0004  * triggering a SEGV.
0005  *
0006  * Based on test code by Tom Lane.
0007  */
0008
0009 #include <err.h>
0010 #include <stdio.h>
0011 #include <stdlib.h>
0012 #include <signal.h>
0013 #include <sys/types.h>
0014 #include <unistd.h>
0015
0016 #include "../pmu/lib.h"
0017 #include "utils.h"
0018
0019 #define _KB (1024)
0020 #define _MB (1024 * 1024)
0021
0022 static char *stack_base_ptr;
0023 static char *stack_top_ptr;
0024
0025 static volatile sig_atomic_t sig_occurred = 0;
0026
0027 static void sigusr1_handler(int signal_arg)
0028 {
0029     sig_occurred = 1;
0030 }
0031
0032 static int consume_stack(unsigned int stack_size, union pipe write_pipe)
0033 {
0034     char stack_cur;
0035
0036     if ((stack_base_ptr - &stack_cur) < stack_size)
0037         return consume_stack(stack_size, write_pipe);
0038     else {
0039         stack_top_ptr = &stack_cur;
0040
0041         FAIL_IF(notify_parent(write_pipe));
0042
0043         while (!sig_occurred)
0044             barrier();
0045     }
0046
0047     return 0;
0048 }
0049
0050 static int child(unsigned int stack_size, union pipe write_pipe)
0051 {
0052     struct sigaction act;
0053     char stack_base;
0054
0055     act.sa_handler = sigusr1_handler;
0056     sigemptyset(&act.sa_mask);
0057     act.sa_flags = 0;
0058     if (sigaction(SIGUSR1, &act, NULL) < 0)
0059         err(1, "sigaction");
0060
0061     stack_base_ptr = (char *) (((size_t) &stack_base + 65535) & ~65535UL);
0062
0063     FAIL_IF(consume_stack(stack_size, write_pipe));
0064
0065     printf("size 0x%06x: OK, stack base %p top %p (%zx used)\n",
0066         stack_size, stack_base_ptr, stack_top_ptr,
0067         stack_base_ptr - stack_top_ptr);
0068
0069     return 0;
0070 }
0071
0072 static int test_one_size(unsigned int stack_size)
0073 {
0074     union pipe read_pipe, write_pipe;
0075     pid_t pid;
0076
0077     FAIL_IF(pipe(read_pipe.fds) == -1);
0078     FAIL_IF(pipe(write_pipe.fds) == -1);
0079
0080     pid = fork();
0081     if (pid == 0) {
0082         close(read_pipe.read_fd);
0083         close(write_pipe.write_fd);
0084         exit(child(stack_size, read_pipe));
0085     }
0086
0087     close(read_pipe.write_fd);
0088     close(write_pipe.read_fd);
0089     FAIL_IF(sync_with_child(read_pipe, write_pipe));
0090
0091     kill(pid, SIGUSR1);
0092
0093     FAIL_IF(wait_for_child(pid));
0094
0095     close(read_pipe.read_fd);
0096     close(write_pipe.write_fd);
0097
0098     return 0;
0099 }
0100
0101 int test(void)
0102 {
0103     unsigned int i, size;
0104
0105     // Test with used stack from 1MB - 64K to 1MB + 64K
0106     // Increment by 64 to get more coverage of odd sizes
0107     for (i = 0; i < (128 * _KB); i += 64) {
0108         size = i + (1 * _MB) - (64 * _KB);
0109         FAIL_IF(test_one_size(size));
0110     }
0111
0112     return 0;
0113 }
0114
0115 int main(void)
0116 {
0117     return test_harness(test, "stack_expansion_signal");
0118 }