5d69cbdfdd
Let's add a test that especially verifies that no data will be touched
in case we cross page boundaries and one page access triggers a fault.
Before the fault-safe handling fixes, the test failes with:
TEST mvc on s390x
data modified during a fault
make[2]: *** [../Makefile.target:116: run-mvc] Error 1
Acked-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: David Hildenbrand <david@redhat.com>
110 lines
2.7 KiB
C
110 lines
2.7 KiB
C
#include <stdint.h>
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#include <stdlib.h>
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#include <stdio.h>
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#include <string.h>
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#include <sys/mman.h>
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#include <signal.h>
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#include <setjmp.h>
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jmp_buf jmp_env;
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static void handle_sigsegv(int sig)
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{
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siglongjmp(jmp_env, 1);
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}
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#define ALLOC_SIZE (2 * 4096)
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static inline void mvc_256(const char *dst, const char *src)
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{
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asm volatile (
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" mvc 0(256,%[dst]),0(%[src])\n"
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:
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: [dst] "d" (dst),
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[src] "d" (src)
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: "memory");
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}
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int main(void)
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{
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char *src, *dst;
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int i;
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/* register the SIGSEGV handler */
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if (signal(SIGSEGV, handle_sigsegv) == SIG_ERR) {
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fprintf(stderr, "SIGSEGV not registered\n");
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return 1;
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}
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/* prepare the buffers - two consecutive pages */
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src = valloc(ALLOC_SIZE);
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dst = valloc(ALLOC_SIZE);
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memset(src, 0xff, ALLOC_SIZE);
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memset(dst, 0x0, ALLOC_SIZE);
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/* protect the second pages */
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if (mprotect(src + 4096, 4096, PROT_NONE) ||
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mprotect(dst + 4096, 4096, PROT_NONE)) {
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fprintf(stderr, "mprotect failed\n");
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return 1;
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}
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/* fault on second destination page */
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if (sigsetjmp(jmp_env, 1) == 0) {
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mvc_256(dst + 4096 - 128, src);
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fprintf(stderr, "fault not triggered\n");
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return 1;
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}
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/* fault on second source page */
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if (sigsetjmp(jmp_env, 1) == 0) {
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mvc_256(dst, src + 4096 - 128);
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fprintf(stderr, "fault not triggered\n");
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return 1;
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}
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/* fault on second source and second destination page */
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if (sigsetjmp(jmp_env, 1) == 0) {
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mvc_256(dst + 4096 - 128, src + 4096 - 128);
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fprintf(stderr, "fault not triggered\n");
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return 1;
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}
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/* restore permissions */
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if (mprotect(src + 4096, 4096, PROT_READ | PROT_WRITE) ||
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mprotect(dst + 4096, 4096, PROT_READ | PROT_WRITE)) {
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fprintf(stderr, "mprotect failed\n");
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return 1;
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}
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/* no data must be touched during the faults */
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for (i = 0; i < ALLOC_SIZE; i++) {
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if (src[i] != 0xff || dst[i]) {
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fprintf(stderr, "data modified during a fault\n");
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return 1;
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}
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}
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/* test if MVC works now correctly accross page boundaries */
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mvc_256(dst + 4096 - 128, src + 4096 - 128);
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for (i = 0; i < ALLOC_SIZE; i++) {
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if (src[i] != 0xff) {
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fprintf(stderr, "src modified\n");
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return 1;
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}
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if (i < 4096 - 128 || i >= 4096 + 128) {
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if (dst[i]) {
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fprintf(stderr, "wrong dst modified\n");
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return 1;
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}
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} else {
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if (dst[i] != 0xff) {
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fprintf(stderr, "wrong data moved\n");
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return 1;
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}
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}
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}
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return 0;
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}
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