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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
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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>
105 lines
2.5 KiB
C
105 lines
2.5 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* Copyright IBM Corp. 2024
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*/
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#ifndef __ASM_S390_MACHINE_H
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#define __ASM_S390_MACHINE_H
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#include <linux/const.h>
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#define MFEATURE_LOWCORE 0
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#define MFEATURE_PCI_MIO 1
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#define MFEATURE_SCC 2
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#define MFEATURE_TLB_GUEST 3
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#define MFEATURE_TX 4
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#define MFEATURE_ESOP 5
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#define MFEATURE_DIAG9C 6
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#define MFEATURE_VM 7
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#define MFEATURE_KVM 8
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#define MFEATURE_LPAR 9
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#define MFEATURE_DIAG288 10
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#ifndef __ASSEMBLY__
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#include <linux/bitops.h>
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#include <asm/alternative.h>
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extern unsigned long machine_features[1];
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#define MAX_MFEATURE_BIT (sizeof(machine_features) * BITS_PER_BYTE)
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static inline void __set_machine_feature(unsigned int nr, unsigned long *mfeatures)
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{
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if (nr >= MAX_MFEATURE_BIT)
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return;
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__set_bit(nr, mfeatures);
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}
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static inline void set_machine_feature(unsigned int nr)
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{
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__set_machine_feature(nr, machine_features);
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}
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static inline void __clear_machine_feature(unsigned int nr, unsigned long *mfeatures)
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{
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if (nr >= MAX_MFEATURE_BIT)
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return;
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__clear_bit(nr, mfeatures);
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}
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static inline void clear_machine_feature(unsigned int nr)
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{
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__clear_machine_feature(nr, machine_features);
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}
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static bool __test_machine_feature(unsigned int nr, unsigned long *mfeatures)
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{
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if (nr >= MAX_MFEATURE_BIT)
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return false;
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return test_bit(nr, mfeatures);
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}
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static bool test_machine_feature(unsigned int nr)
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{
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return __test_machine_feature(nr, machine_features);
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}
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static __always_inline bool __test_machine_feature_constant(unsigned int nr)
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{
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asm goto(
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ALTERNATIVE("brcl 15,%l[l_no]", "brcl 0,0", ALT_FEATURE(%[nr]))
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:
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: [nr] "i" (nr)
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:
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: l_no);
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return true;
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l_no:
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return false;
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}
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#define DEFINE_MACHINE_HAS_FEATURE(name, feature) \
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static __always_inline bool machine_has_##name(void) \
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{ \
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if (!__is_defined(__DECOMPRESSOR) && __builtin_constant_p(feature)) \
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return __test_machine_feature_constant(feature); \
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return test_machine_feature(feature); \
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}
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DEFINE_MACHINE_HAS_FEATURE(relocated_lowcore, MFEATURE_LOWCORE)
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DEFINE_MACHINE_HAS_FEATURE(scc, MFEATURE_SCC)
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DEFINE_MACHINE_HAS_FEATURE(tlb_guest, MFEATURE_TLB_GUEST)
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DEFINE_MACHINE_HAS_FEATURE(tx, MFEATURE_TX)
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DEFINE_MACHINE_HAS_FEATURE(esop, MFEATURE_ESOP)
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DEFINE_MACHINE_HAS_FEATURE(diag9c, MFEATURE_DIAG9C)
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DEFINE_MACHINE_HAS_FEATURE(vm, MFEATURE_VM)
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DEFINE_MACHINE_HAS_FEATURE(kvm, MFEATURE_KVM)
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DEFINE_MACHINE_HAS_FEATURE(lpar, MFEATURE_LPAR)
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#define machine_is_vm machine_has_vm
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#define machine_is_kvm machine_has_kvm
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#define machine_is_lpar machine_has_lpar
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#endif /* __ASSEMBLY__ */
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#endif /* __ASM_S390_MACHINE_H */
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