selftests/powerpc: Add a test of sigreturn vs VDSO (a0968a02) · Commits · 戴 / test

tools/testing/selftests/powerpc/signal/.gitignore

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		signal
		signal_tm
		sigfuz
		sigreturn_vdso

tools/testing/selftests/powerpc/signal/Makefile

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		# SPDX-License-Identifier: GPL-2.0
		TEST_GEN_PROGS := signal signal_tm sigfuz
		TEST_GEN_PROGS := signal signal_tm sigfuz sigreturn_vdso

		CFLAGS += -maltivec
		$(OUTPUT)/signal_tm: CFLAGS += -mhtm

tools/testing/selftests/powerpc/signal/sigreturn_vdso.c

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		// SPDX-License-Identifier: GPL-2.0
		/*
		* Test that we can take signals with and without the VDSO mapped, which trigger
		* different paths in the signal handling code.
		*
		* See handle_rt_signal64() and setup_trampoline() in signal_64.c
		*/

		#define _GNU_SOURCE

		#include <errno.h>
		#include <stdio.h>
		#include <signal.h>
		#include <stdlib.h>
		#include <string.h>
		#include <sys/mman.h>
		#include <sys/types.h>
		#include <unistd.h>

		// Ensure assert() is not compiled out
		#undef NDEBUG
		#include <assert.h>

		#include "utils.h"

		static int search_proc_maps(char needle, unsigned long low, unsigned long *high)
		{
		unsigned long start, end;
		static char buf[4096];
		char name[128];
		FILE *f;
		int rc = -1;

		f = fopen("/proc/self/maps", "r");
		if (!f) {
		perror("fopen");
		return -1;
		}

		while (fgets(buf, sizeof(buf), f)) {
		rc = sscanf(buf, "%lx-%lx %c%c%c%c %x %d:%d %d %127s\n",
		&start, &end, name);
		if (rc == 2)
		continue;

		if (rc != 3) {
		printf("sscanf errored\n");
		rc = -1;
		break;
		}

		if (strstr(name, needle)) {
		*low = start;
		*high = end - 1;
		rc = 0;
		break;
		}
		}

		fclose(f);

		return rc;
		}

		static volatile sig_atomic_t took_signal = 0;

		static void sigusr1_handler(int sig)
		{
		took_signal++;
		}

		int test_sigreturn_vdso(void)
		{
		unsigned long low, high, size;
		struct sigaction act;
		char *p;

		act.sa_handler = sigusr1_handler;
		act.sa_flags = 0;
		sigemptyset(&act.sa_mask);

		assert(sigaction(SIGUSR1, &act, NULL) == 0);

		// Confirm the VDSO is mapped, and work out where it is
		assert(search_proc_maps("[vdso]", &low, &high) == 0);
		size = high - low + 1;
		printf("VDSO is at 0x%lx-0x%lx (%lu bytes)\n", low, high, size);

		kill(getpid(), SIGUSR1);
		assert(took_signal == 1);
		printf("Signal delivered OK with VDSO mapped\n");

		// Remap the VDSO somewhere else
		p = mmap(NULL, size, PROT_READ\|PROT_WRITE, MAP_ANONYMOUS\|MAP_PRIVATE, -1, 0);
		assert(p != MAP_FAILED);
		assert(mremap((void *)low, size, size, MREMAP_MAYMOVE\|MREMAP_FIXED, p) != MAP_FAILED);
		assert(search_proc_maps("[vdso]", &low, &high) == 0);
		size = high - low + 1;
		printf("VDSO moved to 0x%lx-0x%lx (%lu bytes)\n", low, high, size);

		kill(getpid(), SIGUSR1);
		assert(took_signal == 2);
		printf("Signal delivered OK with VDSO moved\n");

		assert(munmap((void *)low, size) == 0);
		printf("Unmapped VDSO\n");

		// Confirm the VDSO is not mapped anymore
		assert(search_proc_maps("[vdso]", &low, &high) != 0);

		// Make the stack executable
		assert(search_proc_maps("[stack]", &low, &high) == 0);
		size = high - low + 1;
		mprotect((void *)low, size, PROT_READ\|PROT_WRITE\|PROT_EXEC);
		printf("Remapped the stack executable\n");

		kill(getpid(), SIGUSR1);
		assert(took_signal == 3);
		printf("Signal delivered OK with VDSO unmapped\n");

		return 0;
		}

		int main(void)
		{
		return test_harness(test_sigreturn_vdso, "sigreturn_vdso");
		}

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