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#include <assert.h>
#include <execinfo.h>
#include <signal.h>
#include <string.h>
#include <sys/mman.h>
#include <ucontext.h>
#include <unistd.h>
/*
* Various instructions that generate SIGILL and SIGSEGV. They could have been
* defined in a separate .s file, but this would complicate the build, so the
* inline asm is used instead.
*/
#define DEFINE_ASM_FUNCTION(name, body) \
asm(".globl " #name "\n" \
#name ":\n" \
".cfi_startproc\n" \
body "\n" \
"br %r14\n" \
".cfi_endproc");
void illegal_op(void);
extern const char after_illegal_op;
DEFINE_ASM_FUNCTION(illegal_op,
".byte 0x00,0x00\n"
".globl after_illegal_op\n"
"after_illegal_op:")
void stg(void *dst, unsigned long src);
DEFINE_ASM_FUNCTION(stg, "stg %r3,0(%r2)")
void mvc_8(void *dst, void *src);
DEFINE_ASM_FUNCTION(mvc_8, "mvc 0(8,%r2),0(%r3)")
extern const char return_from_main_1;
static void safe_puts(const char *s)
{
write(0, s, strlen(s));
write(0, "\n", 1);
}
enum exception {
exception_operation,
exception_translation,
exception_protection,
};
static struct {
int sig;
void *addr;
unsigned long psw_addr;
enum exception exception;
} expected;
static void handle_signal(int sig, siginfo_t *info, void *ucontext)
{
int err, i, n_frames;
void *frames[16];
void *page;
if (sig != expected.sig) {
safe_puts("[ FAILED ] wrong signal");
_exit(1);
}
if (info->si_addr != expected.addr) {
safe_puts("[ FAILED ] wrong si_addr");
_exit(1);
}
if (((ucontext_t *)ucontext)->uc_mcontext.psw.addr != expected.psw_addr) {
safe_puts("[ FAILED ] wrong psw.addr");
_exit(1);
}
switch (expected.exception) {
case exception_translation:
page = mmap(expected.addr, 4096, PROT_READ | PROT_WRITE,
MAP_PRIVATE | MAP_ANONYMOUS | MAP_FIXED, -1, 0);
if (page != expected.addr) {
safe_puts("[ FAILED ] mmap() failed");
_exit(1);
}
break;
case exception_protection:
err = mprotect(expected.addr, 4096, PROT_READ | PROT_WRITE);
if (err != 0) {
safe_puts("[ FAILED ] mprotect() failed");
_exit(1);
}
break;
default:
break;
}
n_frames = backtrace(frames, sizeof(frames) / sizeof(frames[0]));
for (i = 0; i < n_frames; i++) {
if (frames[i] == &return_from_main_1) {
break;
}
}
if (i == n_frames) {
safe_puts("[ FAILED ] backtrace() is broken");
_exit(1);
}
}
static void check_sigsegv(void *func, enum exception exception,
unsigned long val)
{
int prot;
unsigned long *page;
unsigned long *addr;
int err;
prot = exception == exception_translation ? PROT_NONE : PROT_READ;
page = mmap(NULL, 4096, prot, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
assert(page != MAP_FAILED);
if (exception == exception_translation) {
/* Hopefully nothing will be mapped at this address. */
err = munmap(page, 4096);
assert(err == 0);
}
addr = page + (val & 0x1ff);
expected.sig = SIGSEGV;
expected.addr = page;
expected.psw_addr = (unsigned long)func;
expected.exception = exception;
if (func == stg) {
stg(addr, val);
} else {
assert(func == mvc_8);
mvc_8(addr, &val);
}
assert(*addr == val);
err = munmap(page, 4096);
assert(err == 0);
}
int main_1(void)
{
struct sigaction act;
int err;
memset(&act, 0, sizeof(act));
act.sa_sigaction = handle_signal;
act.sa_flags = SA_SIGINFO;
err = sigaction(SIGILL, &act, NULL);
assert(err == 0);
err = sigaction(SIGSEGV, &act, NULL);
assert(err == 0);
safe_puts("[ RUN ] Operation exception");
expected.sig = SIGILL;
expected.addr = illegal_op;
expected.psw_addr = (unsigned long)&after_illegal_op;
expected.exception = exception_operation;
illegal_op();
safe_puts("[ OK ]");
safe_puts("[ RUN ] Translation exception from stg");
check_sigsegv(stg, exception_translation, 42);
safe_puts("[ OK ]");
safe_puts("[ RUN ] Translation exception from mvc");
check_sigsegv(mvc_8, exception_translation, 4242);
safe_puts("[ OK ]");
safe_puts("[ RUN ] Protection exception from stg");
check_sigsegv(stg, exception_protection, 424242);
safe_puts("[ OK ]");
safe_puts("[ RUN ] Protection exception from mvc");
check_sigsegv(mvc_8, exception_protection, 42424242);
safe_puts("[ OK ]");
safe_puts("[ PASSED ]");
_exit(0);
}
/*
* Define main() in assembly in order to test that unwinding from signal
* handlers until main() works. This way we can define a specific point that
* the unwinder should reach. This is also better than defining main() in C
* and using inline assembly to call main_1(), since it's not easy to get all
* the clobbers right.
*/
DEFINE_ASM_FUNCTION(main,
"stmg %r14,%r15,112(%r15)\n"
".cfi_offset 14,-48\n"
".cfi_offset 15,-40\n"
"lay %r15,-160(%r15)\n"
".cfi_def_cfa_offset 320\n"
"brasl %r14,main_1\n"
".globl return_from_main_1\n"
"return_from_main_1:\n"
"lmg %r14,%r15,272(%r15)\n"
".cfi_restore 15\n"
".cfi_restore 14\n"
".cfi_def_cfa_offset 160");
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