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 Cc: Alex Bennée <alex.ben...@linaro.org> Signed-off-by: David Hildenbrand <da...@redhat.com> --- tests/tcg/s390x/Makefile.target | 1 + tests/tcg/s390x/mvc.c | 109 ++++++++++++++++++++++++++++++++ 2 files changed, 110 insertions(+) create mode 100644 tests/tcg/s390x/mvc.c diff --git a/tests/tcg/s390x/Makefile.target b/tests/tcg/s390x/Makefile.target index 6a3bfa8b29..241ef28f61 100644 --- a/tests/tcg/s390x/Makefile.target +++ b/tests/tcg/s390x/Makefile.target @@ -7,3 +7,4 @@ TESTS+=exrl-trt TESTS+=exrl-trtr TESTS+=pack TESTS+=mvo +TESTS+=mvc diff --git a/tests/tcg/s390x/mvc.c b/tests/tcg/s390x/mvc.c new file mode 100644 index 0000000000..aa552d52e5 --- /dev/null +++ b/tests/tcg/s390x/mvc.c @@ -0,0 +1,109 @@ +#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; +} -- 2.21.0