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cpufreq: powernv: fix stack bloat and hard limit on number of CPUs 

commit db0d32d84031188443e25edbd50a71a6e7ac5d1d upstream.

The following build warning occurred on powerpc 64-bit builds:

drivers/cpufreq/powernv-cpufreq.c: In function 'init_chip_info':
drivers/cpufreq/powernv-cpufreq.c:1070:1: warning: the frame size of
1040 bytes is larger than 1024 bytes [-Wframe-larger-than=]

This is with a cross-compiler based on gcc 8.1.0, which I got from:
  https://mirrors.edge.kernel.org/pub/tools/crosstool/files/bin/x86_64/8.1.0/

The warning is due to putting 1024 bytes on the stack:

    unsigned int chip[256];

...and it's also undesirable to have a hard limit on the number of
CPUs here.

Fix both problems by dynamically allocating based on num_possible_cpus,
as recommended by Michael Ellerman.

Fixes: 053819e0bf ("cpufreq: powernv: Handle throttling due to Pmax capping at chip level")
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Cc: 4.10+ <stable@vger.kernel.org> # 4.10+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
John Hubbard 2019-10-30 22:21:59 -07:00 committed by Greg Kroah-Hartman
parent 1b5d4a3a09
commit 5ec6a40b88
1 changed files with 13 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

17
drivers/cpufreq/powernv-cpufreq.c
View File

@ -1041,9 +1041,14 @@ static struct cpufreq_driver powernv_cpufreq_driver = {
static int init_chip_info(void)
{
unsigned int chip[256];
unsigned int *chip;
unsigned int cpu, i;
unsigned int prev_chip_id = UINT_MAX;
int ret = 0;
chip = kcalloc(num_possible_cpus(), sizeof(*chip), GFP_KERNEL);
if (!chip)
return -ENOMEM;
for_each_possible_cpu(cpu) {
unsigned int id = cpu_to_chip_id(cpu);
@ -1055,8 +1060,10 @@ static int init_chip_info(void)
}
chips = kcalloc(nr_chips, sizeof(struct chip), GFP_KERNEL);
if (!chips)
return -ENOMEM;
if (!chips) {
ret = -ENOMEM;
goto free_and_return;
}
for (i = 0; i < nr_chips; i++) {
chips[i].id = chip[i];
@ -1066,7 +1073,9 @@ static int init_chip_info(void)
per_cpu(chip_info, cpu) = &chips[i];
}
return 0;
free_and_return:
kfree(chip);
return ret;
}
static inline void clean_chip_info(void)