selftests/powerpc: Add subpage protection self test.

Signed-off-by: Paul Mackerras <[e-mail]>
Signed-off-by: Aneesh Kumar K.V <[e-mail]>

mpe: Fix compile errors and formatting. Add tempfile logic to Makefile.

Signed-off-by: Michael Ellerman <[e-mail]>

tools/testing/selftests/powerpc/mm/.gitignore

···
 hugetlb_vs_thp_test
+subpage_prot
+tempfile

tools/testing/selftests/powerpc/mm/Makefile

···
 noarg:
 	$(MAKE) -C ../
 
-PROGS := hugetlb_vs_thp_test
+PROGS := hugetlb_vs_thp_test subpage_prot
 
-all: $(PROGS)
+all: $(PROGS) tempfile
 
 $(PROGS): ../harness.c
 
···
 		./$$PROG; \
 	done;
 
+tempfile:
+	dd if=/dev/zero of=tempfile bs=64k count=1
+
 clean:
-	rm -f $(PROGS)
+	rm -f $(PROGS) tempfile
 
 .PHONY: all run_tests clean

tools/testing/selftests/powerpc/mm/subpage_prot.c

···
+/*
+ * Copyright IBM Corp.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of version 2.1 of the GNU Lesser General Public License
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it would be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ */
+
+#include <assert.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <signal.h>
+#include <stdarg.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/mman.h>
+#include <sys/ptrace.h>
+#include <sys/syscall.h>
+#include <ucontext.h>
+#include <unistd.h>
+
+#include "utils.h"
+
+char *file_name;
+
+int in_test;
+volatile int faulted;
+volatile void *dar;
+int errors;
+
+static void segv(int signum, siginfo_t *info, void *ctxt_v)
+{
+	ucontext_t *ctxt = (ucontext_t *)ctxt_v;
+	struct pt_regs *regs = ctxt->uc_mcontext.regs;
+
+	if (!in_test) {
+		fprintf(stderr, "Segfault outside of test !\n");
+		exit(1);
+	}
+
+	faulted = 1;
+	dar = (void *)regs->dar;
+	regs->nip += 4;
+}
+
+static inline void do_read(const volatile void *addr)
+{
+	int ret;
+
+	asm volatile("lwz %0,0(%1); twi 0,%0,0; isync;\n"
+		     : "=r" (ret) : "r" (addr) : "memory");
+}
+
+static inline void do_write(const volatile void *addr)
+{
+	int val = 0x1234567;
+
+	asm volatile("stw %0,0(%1); sync; \n"
+		     : : "r" (val), "r" (addr) : "memory");
+}
+
+static inline void check_faulted(void *addr, long page, long subpage, int write)
+{
+	int want_fault = (subpage == ((page + 3) % 16));
+
+	if (write)
+		want_fault |= (subpage == ((page + 1) % 16));
+
+	if (faulted != want_fault) {
+		printf("Failed at 0x%p (p=%ld,sp=%ld,w=%d), want=%s, got=%s !\n",
+		       addr, page, subpage, write,
+		       want_fault ? "fault" : "pass",
+		       faulted ? "fault" : "pass");
+		++errors;
+	}
+
+	if (faulted) {
+		if (dar != addr) {
+			printf("Fault expected at 0x%p and happened at 0x%p !\n",
+			       addr, dar);
+		}
+		faulted = 0;
+		asm volatile("sync" : : : "memory");
+	}
+}
+
+static int run_test(void *addr, unsigned long size)
+{
+	unsigned int *map;
+	long i, j, pages, err;
+
+	pages = size / 0x10000;
+	map = malloc(pages * 4);
+	assert(map);
+
+	/*
+	 * for each page, mark subpage i % 16 read only and subpage
+	 * (i + 3) % 16 inaccessible
+	 */
+	for (i = 0; i < pages; i++) {
+		map[i] = (0x40000000 >> (((i + 1) * 2) % 32)) |
+			(0xc0000000 >> (((i + 3) * 2) % 32));
+	}
+
+	err = syscall(__NR_subpage_prot, addr, size, map);
+	if (err) {
+		perror("subpage_perm");
+		return 1;
+	}
+	free(map);
+
+	in_test = 1;
+	errors = 0;
+	for (i = 0; i < pages; i++) {
+		for (j = 0; j < 16; j++, addr += 0x1000) {
+			do_read(addr);
+			check_faulted(addr, i, j, 0);
+			do_write(addr);
+			check_faulted(addr, i, j, 1);
+		}
+	}
+
+	in_test = 0;
+	if (errors) {
+		printf("%d errors detected\n", errors);
+		return 1;
+	}
+
+	return 0;
+}
+
+int test_anon(void)
+{
+	unsigned long align;
+	struct sigaction act = {
+		.sa_sigaction = segv,
+		.sa_flags = SA_SIGINFO
+	};
+	void *mallocblock;
+	unsigned long mallocsize;
+
+	if (getpagesize() != 0x10000) {
+		fprintf(stderr, "Kernel page size must be 64K!\n");
+		return 1;
+	}
+
+	sigaction(SIGSEGV, &act, NULL);
+
+	mallocsize = 4 * 16 * 1024 * 1024;
+
+	FAIL_IF(posix_memalign(&mallocblock, 64 * 1024, mallocsize));
+
+	align = (unsigned long)mallocblock;
+	if (align & 0xffff)
+		align = (align | 0xffff) + 1;
+
+	mallocblock = (void *)align;
+
+	printf("allocated malloc block of 0x%lx bytes at 0x%p\n",
+	       mallocsize, mallocblock);
+
+	printf("testing malloc block...\n");
+
+	return run_test(mallocblock, mallocsize);
+}
+
+int test_file(void)
+{
+	struct sigaction act = {
+		.sa_sigaction = segv,
+		.sa_flags = SA_SIGINFO
+	};
+	void *fileblock;
+	off_t filesize;
+	int fd;
+
+	fd = open(file_name, O_RDWR);
+	if (fd == -1) {
+		perror("failed to open file");
+		return 1;
+	}
+	sigaction(SIGSEGV, &act, NULL);
+
+	filesize = lseek(fd, 0, SEEK_END);
+	if (filesize & 0xffff)
+		filesize &= ~0xfffful;
+
+	fileblock = mmap(NULL, filesize, PROT_READ | PROT_WRITE,
+			 MAP_SHARED, fd, 0);
+	if (fileblock == MAP_FAILED) {
+		perror("failed to map file");
+		return 1;
+	}
+	printf("allocated %s for 0x%lx bytes at 0x%p\n",
+	       file_name, filesize, fileblock);
+
+	printf("testing file map...\n");
+
+	return run_test(fileblock, filesize);
+}
+
+int main(int argc, char *argv[])
+{
+	test_harness(test_anon, "subpage_prot_anon");
+
+	if (argc > 1)
+		file_name = argv[1];
+	else
+		file_name = "tempfile";
+
+	test_harness(test_file, "subpage_prot_file");
+
+	return 0;
+}