| 1 |
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| 2 | #include <signal.h>
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| 3 | #include <stdlib.h>
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| 4 | #include <linux/compiler.h>
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| 5 | #include <unistd.h>
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| 6 | #include "../tests.h"
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| 7 |
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| 8 |
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| 9 | noinline void leaf(void);
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| 10 | noinline void parent(void);
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| 11 |
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| 12 | static volatile sig_atomic_t done asm("leafloop_done");
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| 13 |
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| 14 | static void sighandler(int sig __maybe_unused)
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| 15 | {
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| 16 | done = 1;
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| 17 | }
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| 18 |
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| 19 | #if defined(__aarch64__)
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| 20 | |
| 21 | * Write leaf() in assembly so it stays as a minimal leaf function with no
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| 22 | * stack frame and won't get silently broken in the future by any Perf wide
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| 23 | * compilation options like -fstack-protector-all.
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| 24 |
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| 25 | asm(
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| 26 | ".pushsection .text,\"ax\",%progbits\n"
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| 27 | ".global leaf\n"
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| 28 | ".type leaf, %function\n"
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| 29 | "leaf:\n"
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| 30 | " adrp x1, leafloop_done\n"
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| 31 | " ldr w2, [x1, #:lo12:leafloop_done]\n"
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| 32 | " cbz w2, leaf\n"
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| 33 | " ret\n"
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| 34 | ".size leaf, .-leaf\n"
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| 35 | ".popsection\n"
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| 36 | );
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| 37 |
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| 38 | #else
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| 39 |
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| 40 | noinline void leaf(void)
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| 41 | {
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| 42 | while (!done)
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| 43 | ;
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| 44 | }
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| 45 |
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| 46 | #endif
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| 47 |
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| 48 | noinline void parent(void)
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| 49 | {
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| 50 | leaf();
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| 51 | }
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| 52 |
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| 53 | static int leafloop(int argc, const char **argv)
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| 54 | {
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| 55 | int sec = 1;
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| 56 |
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| 57 | if (argc > 0)
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| 58 | sec = atoi(argv[0]);
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| 59 |
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| 60 | signal(SIGINT, sighandler);
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| 61 | signal(SIGALRM, sighandler);
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| 62 | alarm(sec);
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| 63 |
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| 64 | parent();
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| 65 | return 0;
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| 66 | }
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| 67 |
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| 68 | DEFINE_WORKLOAD(leafloop);
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