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Diffstat (limited to 'tools/testing/selftests/powerpc/tm/tm-poison.c')
| -rw-r--r-- | tools/testing/selftests/powerpc/tm/tm-poison.c | 182 |
1 files changed, 182 insertions, 0 deletions
diff --git a/tools/testing/selftests/powerpc/tm/tm-poison.c b/tools/testing/selftests/powerpc/tm/tm-poison.c new file mode 100644 index 000000000..29e5f26af --- /dev/null +++ b/tools/testing/selftests/powerpc/tm/tm-poison.c @@ -0,0 +1,182 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright 2019, Gustavo Romero, Michael Neuling, IBM Corp. + * + * This test will spawn two processes. Both will be attached to the same + * CPU (CPU 0). The child will be in a loop writing to FP register f31 and + * VMX/VEC/Altivec register vr31 a known value, called poison, calling + * sched_yield syscall after to allow the parent to switch on the CPU. + * Parent will set f31 and vr31 to 1 and in a loop will check if f31 and + * vr31 remain 1 as expected until a given timeout (2m). If the issue is + * present child's poison will leak into parent's f31 or vr31 registers, + * otherwise, poison will never leak into parent's f31 and vr31 registers. + */ + +#define _GNU_SOURCE +#include <stdio.h> +#include <stdlib.h> +#include <unistd.h> +#include <inttypes.h> +#include <sched.h> +#include <sys/types.h> +#include <signal.h> +#include <inttypes.h> + +#include "tm.h" + +int tm_poison_test(void) +{ + int cpu, pid; + cpu_set_t cpuset; + uint64_t poison = 0xdeadbeefc0dec0fe; + uint64_t unknown = 0; + bool fail_fp = false; + bool fail_vr = false; + + SKIP_IF(!have_htm()); + + cpu = pick_online_cpu(); + FAIL_IF(cpu < 0); + + // Attach both Child and Parent to the same CPU + CPU_ZERO(&cpuset); + CPU_SET(cpu, &cpuset); + FAIL_IF(sched_setaffinity(0, sizeof(cpuset), &cpuset) != 0); + + pid = fork(); + if (!pid) { + /** + * child + */ + while (1) { + sched_yield(); + asm ( + "mtvsrd 31, %[poison];" // f31 = poison + "mtvsrd 63, %[poison];" // vr31 = poison + + : : [poison] "r" (poison) : ); + } + } + + /** + * parent + */ + asm ( + /* + * Set r3, r4, and f31 to known value 1 before entering + * in transaction. They won't be written after that. + */ + " li 3, 0x1 ;" + " li 4, 0x1 ;" + " mtvsrd 31, 4 ;" + + /* + * The Time Base (TB) is a 64-bit counter register that is + * independent of the CPU clock and which is incremented + * at a frequency of 512000000 Hz, so every 1.953125ns. + * So it's necessary 120s/0.000000001953125s = 61440000000 + * increments to get a 2 minutes timeout. Below we set that + * value in r5 and then use r6 to track initial TB value, + * updating TB values in r7 at every iteration and comparing it + * to r6. When r7 (current) - r6 (initial) > 61440000000 we bail + * out since for sure we spent already 2 minutes in the loop. + * SPR 268 is the TB register. + */ + " lis 5, 14 ;" + " ori 5, 5, 19996 ;" + " sldi 5, 5, 16 ;" // r5 = 61440000000 + + " mfspr 6, 268 ;" // r6 (TB initial) + "1: mfspr 7, 268 ;" // r7 (TB current) + " subf 7, 6, 7 ;" // r7 - r6 > 61440000000 ? + " cmpd 7, 5 ;" + " bgt 3f ;" // yes, exit + + /* + * Main loop to check f31 + */ + " tbegin. ;" // no, try again + " beq 1b ;" // restart if no timeout + " mfvsrd 3, 31 ;" // read f31 + " cmpd 3, 4 ;" // f31 == 1 ? + " bne 2f ;" // broken :-( + " tabort. 3 ;" // try another transaction + "2: tend. ;" // commit transaction + "3: mr %[unknown], 3 ;" // record r3 + + : [unknown] "=r" (unknown) + : + : "cr0", "r3", "r4", "r5", "r6", "r7", "vs31" + + ); + + /* + * On leak 'unknown' will contain 'poison' value from child, + * otherwise (no leak) 'unknown' will contain the same value + * as r3 before entering in transactional mode, i.e. 0x1. + */ + fail_fp = unknown != 0x1; + if (fail_fp) + printf("Unknown value %#"PRIx64" leaked into f31!\n", unknown); + else + printf("Good, no poison or leaked value into FP registers\n"); + + asm ( + /* + * Set r3, r4, and vr31 to known value 1 before entering + * in transaction. They won't be written after that. + */ + " li 3, 0x1 ;" + " li 4, 0x1 ;" + " mtvsrd 63, 4 ;" + + " lis 5, 14 ;" + " ori 5, 5, 19996 ;" + " sldi 5, 5, 16 ;" // r5 = 61440000000 + + " mfspr 6, 268 ;" // r6 (TB initial) + "1: mfspr 7, 268 ;" // r7 (TB current) + " subf 7, 6, 7 ;" // r7 - r6 > 61440000000 ? + " cmpd 7, 5 ;" + " bgt 3f ;" // yes, exit + + /* + * Main loop to check vr31 + */ + " tbegin. ;" // no, try again + " beq 1b ;" // restart if no timeout + " mfvsrd 3, 63 ;" // read vr31 + " cmpd 3, 4 ;" // vr31 == 1 ? + " bne 2f ;" // broken :-( + " tabort. 3 ;" // try another transaction + "2: tend. ;" // commit transaction + "3: mr %[unknown], 3 ;" // record r3 + + : [unknown] "=r" (unknown) + : + : "cr0", "r3", "r4", "r5", "r6", "r7", "vs63" + + ); + + /* + * On leak 'unknown' will contain 'poison' value from child, + * otherwise (no leak) 'unknown' will contain the same value + * as r3 before entering in transactional mode, i.e. 0x1. + */ + fail_vr = unknown != 0x1; + if (fail_vr) + printf("Unknown value %#"PRIx64" leaked into vr31!\n", unknown); + else + printf("Good, no poison or leaked value into VEC registers\n"); + + kill(pid, SIGKILL); + + return (fail_fp | fail_vr); +} + +int main(int argc, char *argv[]) +{ + /* Test completes in about 4m */ + test_harness_set_timeout(250); + return test_harness(tm_poison_test, "tm_poison_test"); +} |