mirror of
https://github.com/raspberrypi/linux.git
synced 2025-12-09 03:20:05 +00:00
1c745df519
The s390 specific diag288_wdt watchdog driver makes use of the virtual watchdog timer, which is available in most machine configurations. If executing the diagnose instruction with subcode 0x288 results in an exception the watchdog timer is not available, otherwise it is available. In order to allow module autoload of the diag288_wdt module, move the detection of the virtual watchdog timer to early boot code, and provide its availability as a cpu feature. This allows to make use of module_cpu_feature_match() to automatically load the module iff the virtual watchdog timer is available. Suggested-by: Marc Hartmayer <mhartmay@linux.ibm.com> Tested-by: Mete Durlu <meted@linux.ibm.com> Acked-by: Guenter Roeck <linux@roeck-us.net> Link: https://lore.kernel.org/r/20250410095036.1525057-1-hca@linux.ibm.com Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
52 lines
1.2 KiB
C
52 lines
1.2 KiB
C
// SPDX-License-Identifier: GPL-2.0
|
|
/*
|
|
* Copyright IBM Corp. 2022
|
|
*/
|
|
|
|
#include <linux/cpufeature.h>
|
|
#include <linux/bug.h>
|
|
#include <asm/machine.h>
|
|
#include <asm/elf.h>
|
|
|
|
enum {
|
|
TYPE_HWCAP,
|
|
TYPE_FACILITY,
|
|
TYPE_MACHINE,
|
|
};
|
|
|
|
struct s390_cpu_feature {
|
|
unsigned int type : 4;
|
|
unsigned int num : 28;
|
|
};
|
|
|
|
static struct s390_cpu_feature s390_cpu_features[MAX_CPU_FEATURES] = {
|
|
[S390_CPU_FEATURE_MSA] = {.type = TYPE_HWCAP, .num = HWCAP_NR_MSA},
|
|
[S390_CPU_FEATURE_VXRS] = {.type = TYPE_HWCAP, .num = HWCAP_NR_VXRS},
|
|
[S390_CPU_FEATURE_UV] = {.type = TYPE_FACILITY, .num = 158},
|
|
[S390_CPU_FEATURE_D288] = {.type = TYPE_MACHINE, .num = MFEATURE_DIAG288},
|
|
};
|
|
|
|
/*
|
|
* cpu_have_feature - Test CPU features on module initialization
|
|
*/
|
|
int cpu_have_feature(unsigned int num)
|
|
{
|
|
struct s390_cpu_feature *feature;
|
|
|
|
if (WARN_ON_ONCE(num >= MAX_CPU_FEATURES))
|
|
return 0;
|
|
feature = &s390_cpu_features[num];
|
|
switch (feature->type) {
|
|
case TYPE_HWCAP:
|
|
return !!(elf_hwcap & BIT(feature->num));
|
|
case TYPE_FACILITY:
|
|
return test_facility(feature->num);
|
|
case TYPE_MACHINE:
|
|
return test_machine_feature(feature->num);
|
|
default:
|
|
WARN_ON_ONCE(1);
|
|
return 0;
|
|
}
|
|
}
|
|
EXPORT_SYMBOL(cpu_have_feature);
|