| 1 | // SPDX-License-Identifier: GPL-2.0-only |
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| 2 | /* |
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| 3 | * Copyright 2015, Michael Neuling, IBM Corp. |
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| 4 | * |
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| 5 | * Test the kernel's signal delievery code to ensure that we don't |
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| 6 | * trelaim twice in the kernel signal delivery code. This can happen |
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| 7 | * if we trigger a signal when in a transaction and the stack pointer |
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| 8 | * is bogus. |
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| 9 | * |
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| 10 | * This test case registers a SEGV handler, sets the stack pointer |
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| 11 | * (r1) to NULL, starts a transaction and then generates a SEGV. The |
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| 12 | * SEGV should be handled but we exit here as the stack pointer is |
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| 13 | * invalid and hance we can't sigreturn. We only need to check that |
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| 14 | * this flow doesn't crash the kernel. |
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| 15 | */ |
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| 16 | |
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| 17 | #include <unistd.h> |
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| 18 | #include <sys/types.h> |
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| 19 | #include <sys/wait.h> |
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| 20 | #include <stdlib.h> |
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| 21 | #include <stdio.h> |
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| 22 | #include <signal.h> |
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| 23 | |
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| 24 | #include "utils.h" |
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| 25 | #include "tm.h" |
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| 26 | |
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| 27 | void signal_segv(int signum) |
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| 28 | { |
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| 29 | /* This should never actually run since stack is foobar */ |
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| 30 | exit(1); |
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| 31 | } |
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| 32 | |
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| 33 | int tm_signal_stack() |
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| 34 | { |
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| 35 | int pid; |
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| 36 | |
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| 37 | SKIP_IF(!have_htm()); |
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| 38 | SKIP_IF(htm_is_synthetic()); |
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| 39 | |
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| 40 | pid = fork(); |
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| 41 | if (pid < 0) |
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| 42 | exit(1); |
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| 43 | |
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| 44 | if (pid) { /* Parent */ |
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| 45 | /* |
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| 46 | * It's likely the whole machine will crash here so if |
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| 47 | * the child ever exits, we are good. |
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| 48 | */ |
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| 49 | wait(NULL); |
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| 50 | return 0; |
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| 51 | } |
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| 52 | |
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| 53 | /* |
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| 54 | * The flow here is: |
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| 55 | * 1) register a signal handler (so signal delievery occurs) |
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| 56 | * 2) make stack pointer (r1) = NULL |
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| 57 | * 3) start transaction |
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| 58 | * 4) cause segv |
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| 59 | */ |
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| 60 | if (signal(SIGSEGV, signal_segv) == SIG_ERR) |
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| 61 | exit(1); |
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| 62 | asm volatile("li 1, 0 ;" /* stack ptr == NULL */ |
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| 63 | "1:" |
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| 64 | "tbegin.;" |
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| 65 | "beq 1b ;" /* retry forever */ |
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| 66 | "tsuspend.;" |
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| 67 | "ld 2, 0(1) ;" /* trigger segv" */ |
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| 68 | : : : "memory" ); |
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| 69 | |
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| 70 | /* This should never get here due to above segv */ |
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| 71 | return 1; |
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| 72 | } |
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| 73 | |
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| 74 | int main(void) |
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| 75 | { |
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| 76 | return test_harness(tm_signal_stack, "tm_signal_stack" ); |
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| 77 | } |
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| 78 | |
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