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#include <stddef.h>
#include <stdio.h>
#include <string.h>
#include <sys/mman.h>
#define DEFINE_ASM(_name, _code) \
extern const char _name[]; \
extern const char _name ## _end[]; \
asm(" .globl " #_name "\n" \
#_name ":\n" \
" " _code "\n" \
" .globl " #_name "_end\n" \
#_name "_end:\n");
DEFINE_ASM(br_r14, "br %r14");
DEFINE_ASM(brasl_r0, "brasl %r0,-0x100000000");
DEFINE_ASM(brcl_0xf, "brcl 0xf,-0x100000000");
struct test {
const char *code;
const char *code_end;
};
static const struct test tests[] = {
{
.code = brasl_r0,
.code_end = brasl_r0_end,
},
{
.code = brcl_0xf,
.code_end = brcl_0xf_end,
},
};
int main(void)
{
unsigned char *buf;
size_t length = 0;
size_t i;
for (i = 0; i < sizeof(tests) / sizeof(tests[0]); i++) {
size_t test_length = 0x100000000 + (tests[i].code_end - tests[i].code);
if (test_length > length) {
length = test_length;
}
}
buf = mmap(NULL, length, PROT_READ | PROT_WRITE | PROT_EXEC,
MAP_PRIVATE | MAP_ANONYMOUS | MAP_NORESERVE, -1, 0);
if (buf == MAP_FAILED) {
perror("SKIP: mmap() failed");
return 0;
}
memcpy(buf, br_r14, br_r14_end - br_r14);
for (i = 0; i < sizeof(tests) / sizeof(tests[0]); i++) {
void (*code)(void) = (void *)(buf + 0x100000000);
memcpy(code, tests[i].code, tests[i].code_end - tests[i].code);
code();
memset(code, 0, tests[i].code_end - tests[i].code);
}
munmap(buf, length);
return 0;
}
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