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// SPDX-License-Identifier: MIT
/*
* Copyright © 2021 Intel Corporation
*/
#include <stdio.h>
#include "igt_taints.h"
/* see Linux's include/linux/kernel.h */
static const struct {
int bit;
int bad;
const char *explanation;
} abort_taints[] = {
{ 5, 1, "TAINT_BAD_PAGE: Bad page reference or an unexpected page flags." },
{ 7, 1, "TAINT_DIE: Kernel has died - BUG/OOPS." },
{ 9, 1, "TAINT_WARN: WARN_ON has happened." },
{ -1 }
};
/**
* igt_explain_taints:
* @taints: mask of taints requiring an explanation [inout]
*
* Inspects the mask and looks up the first reason corresponding to a set
* bit in the mask. It returns the reason as a string constant, and removes
* the bit from the mask. If the mask is empty, or we have no known reason
* matching the mask, NULL is returned.
*
* This may be used in a loop to extract all known reasons for why the
* kernel is tainted:
*
* while (reason = igt_explain_taints(&taints))
* igt_info("%s", reason);
*
* Returns the first reason corresponding to a taint bit.
*/
const char *igt_explain_taints(unsigned long *taints)
{
for (typeof(*abort_taints) *taint = abort_taints;
taint->bit >= 0;
taint++) {
if (*taints & (1ul << taint->bit)) {
*taints &= ~(1ul << taint->bit);
return taint->explanation;
}
}
return NULL;
}
/**
* igt_bad_taints:
*
* Returns the mask of kernel taints that IGT considers fatal.
* Such as TAINT_WARN set when the kernel oopses.
*/
unsigned long igt_bad_taints(void)
{
static unsigned long bad_taints;
if (!bad_taints) {
for (typeof(*abort_taints) *taint = abort_taints;
taint->bit >= 0;
taint++) {
if (taint->bad)
bad_taints |= 1ul << taint->bit;
}
}
return bad_taints;
}
/**
* igt_kernel_tainted:
* @taints: bitmask of kernel taints [out]
*
* Reads the bitmask of kernel taints from "/proc/sys/kernel/tainted",
* see linux/kernel.h for the full set of flags. These are set whenever
* the kernel encounters an exceptional condition that may impair functionality.
* The kernel only sets the taint once, and so once a "fatal" condition has
* been encountered, it is generally not advisable to continue testing, as at
* least all future taint reporting will be lost.
*
* igt_kernel_tainted() returns the set of _all_ taints reported via @taints,
* and also the set of _fatal_ taints as its return value.
*
* Returns a mask of fatal taints; 0 if untainted.
*/
unsigned long igt_kernel_tainted(unsigned long *taints)
{
FILE *f;
*taints = 0;
f = fopen("/proc/sys/kernel/tainted", "r");
if (f) {
fscanf(f, "%lu", taints);
fclose(f);
}
return is_tainted(*taints);
}
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