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		1d9ac91baf
		
	
	
	
	
		
			
			The note test requires gcc 10 for -mbranch-protection=standard. The mmap test uses PROT_BTI and does not require special compiler support. Acked-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org> Message-id: 20201021173749.111103-13-richard.henderson@linaro.org Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
		
			
				
	
	
		
			117 lines
		
	
	
		
			2.5 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			117 lines
		
	
	
		
			2.5 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
| /*
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|  * Branch target identification, basic notskip cases.
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|  */
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| 
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| #include <stdio.h>
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| #include <signal.h>
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| #include <string.h>
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| #include <unistd.h>
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| #include <sys/mman.h>
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| 
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| #ifndef PROT_BTI
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| #define PROT_BTI  0x10
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| #endif
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| 
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| static void skip2_sigill(int sig, siginfo_t *info, void *vuc)
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| {
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|     ucontext_t *uc = vuc;
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|     uc->uc_mcontext.pc += 8;
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|     uc->uc_mcontext.pstate = 1;
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| }
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| 
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| #define NOP       "nop"
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| #define BTI_N     "hint #32"
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| #define BTI_C     "hint #34"
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| #define BTI_J     "hint #36"
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| #define BTI_JC    "hint #38"
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| 
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| #define BTYPE_1(DEST)    \
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|     "mov x1, #1\n\t"     \
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|     "adr x16, 1f\n\t"    \
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|     "br x16\n"           \
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| "1: " DEST "\n\t"        \
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|     "mov x1, #0"
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| 
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| #define BTYPE_2(DEST)    \
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|     "mov x1, #1\n\t"     \
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|     "adr x16, 1f\n\t"    \
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|     "blr x16\n"          \
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| "1: " DEST "\n\t"        \
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|     "mov x1, #0"
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| 
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| #define BTYPE_3(DEST)    \
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|     "mov x1, #1\n\t"     \
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|     "adr x15, 1f\n\t"    \
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|     "br x15\n"           \
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| "1: " DEST "\n\t"        \
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|     "mov x1, #0"
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| 
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| #define TEST(WHICH, DEST, EXPECT) \
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|     WHICH(DEST) "\n"              \
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|     ".if " #EXPECT "\n\t"         \
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|     "eor x1, x1," #EXPECT "\n"    \
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|     ".endif\n\t"                  \
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|     "add x0, x0, x1\n\t"
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| 
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| asm("\n"
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| "test_begin:\n\t"
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|     BTI_C "\n\t"
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|     "mov x2, x30\n\t"
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|     "mov x0, #0\n\t"
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| 
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|     TEST(BTYPE_1, NOP, 1)
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|     TEST(BTYPE_1, BTI_N, 1)
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|     TEST(BTYPE_1, BTI_C, 0)
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|     TEST(BTYPE_1, BTI_J, 0)
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|     TEST(BTYPE_1, BTI_JC, 0)
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| 
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|     TEST(BTYPE_2, NOP, 1)
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|     TEST(BTYPE_2, BTI_N, 1)
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|     TEST(BTYPE_2, BTI_C, 0)
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|     TEST(BTYPE_2, BTI_J, 1)
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|     TEST(BTYPE_2, BTI_JC, 0)
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| 
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|     TEST(BTYPE_3, NOP, 1)
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|     TEST(BTYPE_3, BTI_N, 1)
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|     TEST(BTYPE_3, BTI_C, 1)
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|     TEST(BTYPE_3, BTI_J, 0)
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|     TEST(BTYPE_3, BTI_JC, 0)
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| 
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|     "ret x2\n"
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| "test_end:"
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| );
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| 
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| int main()
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| {
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|     struct sigaction sa;
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|     void *tb, *te;
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| 
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|     void *p = mmap(0, getpagesize(),
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|                    PROT_EXEC | PROT_READ | PROT_WRITE | PROT_BTI,
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|                    MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
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|     if (p == MAP_FAILED) {
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|         perror("mmap");
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|         return 1;
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|     }
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| 
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|     memset(&sa, 0, sizeof(sa));
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|     sa.sa_sigaction = skip2_sigill;
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|     sa.sa_flags = SA_SIGINFO;
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|     if (sigaction(SIGILL, &sa, NULL) < 0) {
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|         perror("sigaction");
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|         return 1;
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|     }
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| 
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|     /*
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|      * ??? With "extern char test_begin[]", some compiler versions
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|      * will use :got references, and some linker versions will
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|      * resolve this reference to a static symbol incorrectly.
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|      * Bypass this error by using a pc-relative reference directly.
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|      */
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|     asm("adr %0, test_begin; adr %1, test_end" : "=r"(tb), "=r"(te));
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| 
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|     memcpy(p, tb, te - tb);
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| 
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|     return ((int (*)(void))p)();
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| }
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