Commit 5d69cbdf authored by David Hildenbrand's avatar David Hildenbrand
Browse files

tests/tcg: target/s390x: Test MVC 



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: default avatarAlex Bennée <alex.bennee@linaro.org>
Reviewed-by: default avatarRichard Henderson <richard.henderson@linaro.org>
Signed-off-by: default avatarDavid Hildenbrand <david@redhat.com>
parent d9e13c34

tests/tcg/s390x/Makefile.target

+1 −0
Original line number Diff line number Diff line
@@ -7,3 +7,4 @@ TESTS+=exrl-trt 
TESTS+=exrl-trtr

TESTS+=pack

TESTS+=mvo

TESTS+=mvc

tests/tcg/s390x/mvc.c

0 → 100644
+109 −0
Original line number Diff line number Diff line 
#include <stdint.h>

#include <stdlib.h>

#include <stdio.h>

#include <string.h>

#include <sys/mman.h>

#include <signal.h>

#include <setjmp.h>



jmp_buf jmp_env;



static void handle_sigsegv(int sig)

{

    siglongjmp(jmp_env, 1);

}



#define ALLOC_SIZE (2 * 4096)



static inline void mvc_256(const char *dst, const char *src)

{

    asm volatile (

        "    mvc 0(256,%[dst]),0(%[src])\n"

        :

        : [dst] "d" (dst),

          [src] "d" (src)

        : "memory");

}



int main(void)

{

    char *src, *dst;

    int i;



    /* register the SIGSEGV handler */

    if (signal(SIGSEGV, handle_sigsegv) == SIG_ERR) {

        fprintf(stderr, "SIGSEGV not registered\n");

        return 1;

    }



    /* prepare the buffers - two consecutive pages */

    src = valloc(ALLOC_SIZE);

    dst = valloc(ALLOC_SIZE);

    memset(src, 0xff, ALLOC_SIZE);

    memset(dst, 0x0, ALLOC_SIZE);



    /* protect the second pages */

    if (mprotect(src + 4096, 4096, PROT_NONE) ||

        mprotect(dst + 4096, 4096, PROT_NONE)) {

        fprintf(stderr, "mprotect failed\n");

        return 1;

    }



    /* fault on second destination page */

    if (sigsetjmp(jmp_env, 1) == 0) {

        mvc_256(dst + 4096 - 128, src);

        fprintf(stderr, "fault not triggered\n");

        return 1;

    }



    /* fault on second source page */

    if (sigsetjmp(jmp_env, 1) == 0) {

        mvc_256(dst, src + 4096 - 128);

        fprintf(stderr, "fault not triggered\n");

        return 1;

    }



    /* fault on second source and second destination page */

    if (sigsetjmp(jmp_env, 1) == 0) {

        mvc_256(dst + 4096 - 128, src + 4096 - 128);

        fprintf(stderr, "fault not triggered\n");

        return 1;

    }



    /* restore permissions */

    if (mprotect(src + 4096, 4096, PROT_READ | PROT_WRITE) ||

        mprotect(dst + 4096, 4096, PROT_READ | PROT_WRITE)) {

        fprintf(stderr, "mprotect failed\n");

        return 1;

    }



    /* no data must be touched during the faults */

    for (i = 0; i < ALLOC_SIZE; i++) {

        if (src[i] != 0xff || dst[i]) {

            fprintf(stderr, "data modified during a fault\n");

            return 1;

        }

    }



    /* test if MVC works now correctly accross page boundaries */

    mvc_256(dst + 4096 - 128, src + 4096 - 128);

    for (i = 0; i < ALLOC_SIZE; i++) {

        if (src[i] != 0xff) {

            fprintf(stderr, "src modified\n");

            return 1;

        }

        if (i < 4096 - 128 || i >= 4096 + 128) {

            if (dst[i]) {

                fprintf(stderr, "wrong dst modified\n");

                return 1;

            }

        } else {

            if (dst[i] != 0xff) {

                fprintf(stderr, "wrong data moved\n");

                return 1;

            }

        }

    }



    return 0;

}