diff options
| author | Ben Hutchings <ben@decadent.org.uk> | 2018-09-16 16:05:53 +0100 |
|---|---|---|
| committer | Len Brown <len.brown@intel.com> | 2019-08-31 14:48:24 -0400 |
| commit | adb8049097a9ec4acd09fbd3aa8636199a78df8a (patch) | |
| tree | 53f64a739d15e67245f156603a4a2fbe3be10e94 | |
| parent | a55aa89aab90fae7c815b0551b07be37db359d76 (diff) | |
tools/power x86_energy_perf_policy: Fix "uninitialized variable" warnings at -O2
x86_energy_perf_policy first uses __get_cpuid() to check the maximum
CPUID level and exits if it is too low. It then assumes that later
calls will succeed (which I think is architecturally guaranteed). It
also assumes that CPUID works at all (which is not guaranteed on
x86_32).
If optimisations are enabled, gcc warns about potentially
uninitialized variables. Fix this by adding an exit-on-error after
every call to __get_cpuid() instead of just checking the maximum
level.
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Len Brown <len.brown@intel.com>
| -rw-r--r-- | tools/power/x86/x86_energy_perf_policy/x86_energy_perf_policy.c | 26 |
1 files changed, 15 insertions, 11 deletions
diff --git a/tools/power/x86/x86_energy_perf_policy/x86_energy_perf_policy.c b/tools/power/x86/x86_energy_perf_policy/x86_energy_perf_policy.c index 34a796b303fe..7663abef51e9 100644 --- a/tools/power/x86/x86_energy_perf_policy/x86_energy_perf_policy.c +++ b/tools/power/x86/x86_energy_perf_policy/x86_energy_perf_policy.c @@ -1259,6 +1259,15 @@ void probe_dev_msr(void) if (system("/sbin/modprobe msr > /dev/null 2>&1")) err(-5, "no /dev/cpu/0/msr, Try \"# modprobe msr\" "); } + +static void get_cpuid_or_exit(unsigned int leaf, + unsigned int *eax, unsigned int *ebx, + unsigned int *ecx, unsigned int *edx) +{ + if (!__get_cpuid(leaf, eax, ebx, ecx, edx)) + errx(1, "Processor not supported\n"); +} + /* * early_cpuid() * initialize turbo_is_enabled, has_hwp, has_epb @@ -1266,15 +1275,10 @@ void probe_dev_msr(void) */ void early_cpuid(void) { - unsigned int eax, ebx, ecx, edx, max_level; + unsigned int eax, ebx, ecx, edx; unsigned int fms, family, model; - __get_cpuid(0, &max_level, &ebx, &ecx, &edx); - - if (max_level < 6) - errx(1, "Processor not supported\n"); - - __get_cpuid(1, &fms, &ebx, &ecx, &edx); + get_cpuid_or_exit(1, &fms, &ebx, &ecx, &edx); family = (fms >> 8) & 0xf; model = (fms >> 4) & 0xf; if (family == 6 || family == 0xf) @@ -1288,7 +1292,7 @@ void early_cpuid(void) bdx_highest_ratio = msr & 0xFF; } - __get_cpuid(0x6, &eax, &ebx, &ecx, &edx); + get_cpuid_or_exit(0x6, &eax, &ebx, &ecx, &edx); turbo_is_enabled = (eax >> 1) & 1; has_hwp = (eax >> 7) & 1; has_epb = (ecx >> 3) & 1; @@ -1306,7 +1310,7 @@ void parse_cpuid(void) eax = ebx = ecx = edx = 0; - __get_cpuid(0, &max_level, &ebx, &ecx, &edx); + get_cpuid_or_exit(0, &max_level, &ebx, &ecx, &edx); if (ebx == 0x756e6547 && edx == 0x49656e69 && ecx == 0x6c65746e) genuine_intel = 1; @@ -1315,7 +1319,7 @@ void parse_cpuid(void) fprintf(stderr, "CPUID(0): %.4s%.4s%.4s ", (char *)&ebx, (char *)&edx, (char *)&ecx); - __get_cpuid(1, &fms, &ebx, &ecx, &edx); + get_cpuid_or_exit(1, &fms, &ebx, &ecx, &edx); family = (fms >> 8) & 0xf; model = (fms >> 4) & 0xf; stepping = fms & 0xf; @@ -1340,7 +1344,7 @@ void parse_cpuid(void) errx(1, "CPUID: no MSR"); - __get_cpuid(0x6, &eax, &ebx, &ecx, &edx); + get_cpuid_or_exit(0x6, &eax, &ebx, &ecx, &edx); /* turbo_is_enabled already set */ /* has_hwp already set */ has_hwp_notify = eax & (1 << 8); |