72 lines
2.1 KiB
Diff
72 lines
2.1 KiB
Diff
From c149b054fe5b1851860fd01d54596ea75f5008d3 Mon Sep 17 00:00:00 2001
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From: Sandipan Das <sandipan.das@amd.com>
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Date: Wed, 13 Apr 2022 11:45:08 +0530
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Subject: [PATCH 09/15] x86: Fix clock frequency parsing
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AMD processors do not advertise a base clock frequency as
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a part of the "model name" in /proc/cpuinfo. The parsing
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must fail in order to let os_calibrate() determine clock
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speed from cpufreq information or from TSC instead.
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Since the parser fails to find "@", strcspn() returns the
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length of the line instead and sscanf() ends up scanning
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garbage values beyond the null terminator that match the
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format specifier. To avoid this, add an additional check
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that makes the condition fail if "@" is not found.
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Fixes: eaeed92 ("Powerpc: Fix CPU% utilization for PowerVMs")
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Signed-off-by: Sandipan Das <sandipan.das@amd.com>
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---
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x86/util.c | 19 ++++++++++++++-----
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1 file changed, 14 insertions(+), 5 deletions(-)
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diff --git a/x86/util.c b/x86/util.c
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index fdff877..655a677 100644
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--- a/x86/util.c
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+++ b/x86/util.c
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@@ -67,27 +67,36 @@ rdtsc(void)
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/*
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* Check the cpu name in proc info. Intel CPUs always have @ x.y
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- * Ghz and that is the TSC frequency.
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+ * GHz and that is the TSC frequency. AMD CPUs do not advertise
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+ * clock frequency as a part of the model name.
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*/
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int
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arch__cpuinfo_freq(double *freq, char *unit)
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{
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FILE *f;
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char *line = NULL;
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- size_t len = 0;
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+ size_t idx, len = 0;
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int ret = -1;
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if ((f = fopen(CPUINFO_PATH, "r")) == NULL) {
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return (-1);
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}
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- while (getline(&line, &len, f) > 0) {
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+ while ((len = getline(&line, &len, f)) > 0) {
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if (strncmp(line, "model name", sizeof ("model name") - 1) != 0) {
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continue;
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}
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- if (sscanf(line + strcspn(line, "@") + 1, "%lf%10s",
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- freq, unit) == 2) {
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+ idx = strcspn(line, "@") + 1;
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+
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+ /*
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+ * The model name will not change for other processors. So
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+ * bail out if "@" is not found.
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+ */
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+ if (idx >= len)
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+ break;
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+
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+ if (sscanf(line + idx, "%lf%10s", freq, unit) == 2) {
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if (strcasecmp(unit, "GHz") == 0) {
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*freq *= GHZ;
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} else if (strcasecmp(unit, "Mhz") == 0) {
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--
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2.31.1
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