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/*
* Branch target identification, basic notskip cases.
*/
#include <stdio.h>
#include <signal.h>
#include <string.h>
#include <unistd.h>
#include <sys/mman.h>
#ifndef PROT_BTI
#define PROT_BTI 0x10
#endif
static void skip2_sigill(int sig, siginfo_t *info, void *vuc)
{
ucontext_t *uc = vuc;
uc->uc_mcontext.pc += 8;
uc->uc_mcontext.pstate = 1;
}
#define NOP "nop"
#define BTI_N "hint #32"
#define BTI_C "hint #34"
#define BTI_J "hint #36"
#define BTI_JC "hint #38"
#define BTYPE_1(DEST) \
"mov x1, #1\n\t" \
"adr x16, 1f\n\t" \
"br x16\n" \
"1: " DEST "\n\t" \
"mov x1, #0"
#define BTYPE_2(DEST) \
"mov x1, #1\n\t" \
"adr x16, 1f\n\t" \
"blr x16\n" \
"1: " DEST "\n\t" \
"mov x1, #0"
#define BTYPE_3(DEST) \
"mov x1, #1\n\t" \
"adr x15, 1f\n\t" \
"br x15\n" \
"1: " DEST "\n\t" \
"mov x1, #0"
#define TEST(WHICH, DEST, EXPECT) \
WHICH(DEST) "\n" \
".if " #EXPECT "\n\t" \
"eor x1, x1," #EXPECT "\n" \
".endif\n\t" \
"add x0, x0, x1\n\t"
asm("\n"
"test_begin:\n\t"
BTI_C "\n\t"
"mov x2, x30\n\t"
"mov x0, #0\n\t"
TEST(BTYPE_1, NOP, 1)
TEST(BTYPE_1, BTI_N, 1)
TEST(BTYPE_1, BTI_C, 0)
TEST(BTYPE_1, BTI_J, 0)
TEST(BTYPE_1, BTI_JC, 0)
TEST(BTYPE_2, NOP, 1)
TEST(BTYPE_2, BTI_N, 1)
TEST(BTYPE_2, BTI_C, 0)
TEST(BTYPE_2, BTI_J, 1)
TEST(BTYPE_2, BTI_JC, 0)
TEST(BTYPE_3, NOP, 1)
TEST(BTYPE_3, BTI_N, 1)
TEST(BTYPE_3, BTI_C, 1)
TEST(BTYPE_3, BTI_J, 0)
TEST(BTYPE_3, BTI_JC, 0)
"ret x2\n"
"test_end:"
);
int main()
{
struct sigaction sa;
void *tb, *te;
void *p = mmap(0, getpagesize(),
PROT_EXEC | PROT_READ | PROT_WRITE | PROT_BTI,
MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
if (p == MAP_FAILED) {
perror("mmap");
return 1;
}
memset(&sa, 0, sizeof(sa));
sa.sa_sigaction = skip2_sigill;
sa.sa_flags = SA_SIGINFO;
if (sigaction(SIGILL, &sa, NULL) < 0) {
perror("sigaction");
return 1;
}
/*
* ??? With "extern char test_begin[]", some compiler versions
* will use :got references, and some linker versions will
* resolve this reference to a static symbol incorrectly.
* Bypass this error by using a pc-relative reference directly.
*/
asm("adr %0, test_begin; adr %1, test_end" : "=r"(tb), "=r"(te));
memcpy(p, tb, te - tb);
return ((int (*)(void))p)();
}
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