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Commit adb80490 authored by Ben Hutchings's avatar Ben Hutchings Committed by Len Brown
Browse files

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: default avatarBen Hutchings <ben@decadent.org.uk>
Signed-off-by: default avatarLen Brown <len.brown@intel.com>
parent a55aa89a

tools/power/x86/x86_energy_perf_policy/x86_energy_perf_policy.c

+15 −11
Original line number Diff line number Diff line
@@ -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);