From cf1489984641369611556bf00c48f945c77bcf02 Mon Sep 17 00:00:00 2001 From: Martin Schwidefsky Date: Tue, 16 Jan 2018 07:03:44 +0100 Subject: [PATCH] s390/alternative: use a copy of the facility bit mask To be able to switch off specific CPU alternatives with kernel parameters make a copy of the facility bit mask provided by STFLE and use the copy for the decision to apply an alternative. Reviewed-by: David Hildenbrand Reviewed-by: Cornelia Huck Signed-off-by: Martin Schwidefsky --- arch/s390/include/asm/facility.h | 18 ++++++++++++++++++ arch/s390/include/asm/lowcore.h | 3 ++- arch/s390/kernel/alternative.c | 3 ++- arch/s390/kernel/early.c | 3 +++ arch/s390/kernel/setup.c | 4 +++- arch/s390/kernel/smp.c | 4 +++- 6 files changed, 31 insertions(+), 4 deletions(-) diff --git a/arch/s390/include/asm/facility.h b/arch/s390/include/asm/facility.h index fbe0c4b..99c8ce3 100644 --- a/arch/s390/include/asm/facility.h +++ b/arch/s390/include/asm/facility.h @@ -15,6 +15,24 @@ #define MAX_FACILITY_BIT (sizeof(((struct lowcore *)0)->stfle_fac_list) * 8) +static inline void __set_facility(unsigned long nr, void *facilities) +{ + unsigned char *ptr = (unsigned char *) facilities; + + if (nr >= MAX_FACILITY_BIT) + return; + ptr[nr >> 3] |= 0x80 >> (nr & 7); +} + +static inline void __clear_facility(unsigned long nr, void *facilities) +{ + unsigned char *ptr = (unsigned char *) facilities; + + if (nr >= MAX_FACILITY_BIT) + return; + ptr[nr >> 3] &= ~(0x80 >> (nr & 7)); +} + static inline int __test_facility(unsigned long nr, void *facilities) { unsigned char *ptr; diff --git a/arch/s390/include/asm/lowcore.h b/arch/s390/include/asm/lowcore.h index ec6592e..c63986a 100644 --- a/arch/s390/include/asm/lowcore.h +++ b/arch/s390/include/asm/lowcore.h @@ -151,7 +151,8 @@ struct lowcore { __u8 pad_0x0e20[0x0f00-0x0e20]; /* 0x0e20 */ /* Extended facility list */ - __u64 stfle_fac_list[32]; /* 0x0f00 */ + __u64 stfle_fac_list[16]; /* 0x0f00 */ + __u64 alt_stfle_fac_list[16]; /* 0x0f80 */ __u8 pad_0x1000[0x11b0-0x1000]; /* 0x1000 */ /* Pointer to the machine check extended save area */ diff --git a/arch/s390/kernel/alternative.c b/arch/s390/kernel/alternative.c index 574e776..1abf4f3 100644 --- a/arch/s390/kernel/alternative.c +++ b/arch/s390/kernel/alternative.c @@ -75,7 +75,8 @@ static void __init_or_module __apply_alternatives(struct alt_instr *start, instr = (u8 *)&a->instr_offset + a->instr_offset; replacement = (u8 *)&a->repl_offset + a->repl_offset; - if (!test_facility(a->facility)) + if (!__test_facility(a->facility, + S390_lowcore.alt_stfle_fac_list)) continue; if (unlikely(a->instrlen % 2 || a->replacementlen % 2)) { diff --git a/arch/s390/kernel/early.c b/arch/s390/kernel/early.c index 497a920..510f218 100644 --- a/arch/s390/kernel/early.c +++ b/arch/s390/kernel/early.c @@ -193,6 +193,9 @@ static noinline __init void setup_facility_list(void) { stfle(S390_lowcore.stfle_fac_list, ARRAY_SIZE(S390_lowcore.stfle_fac_list)); + memcpy(S390_lowcore.alt_stfle_fac_list, + S390_lowcore.stfle_fac_list, + sizeof(S390_lowcore.alt_stfle_fac_list)); } static __init void detect_diag9c(void) diff --git a/arch/s390/kernel/setup.c b/arch/s390/kernel/setup.c index 793da97..bcd2a4a 100644 --- a/arch/s390/kernel/setup.c +++ b/arch/s390/kernel/setup.c @@ -340,7 +340,9 @@ static void __init setup_lowcore(void) lc->preempt_count = S390_lowcore.preempt_count; lc->stfl_fac_list = S390_lowcore.stfl_fac_list; memcpy(lc->stfle_fac_list, S390_lowcore.stfle_fac_list, - MAX_FACILITY_BIT/8); + sizeof(lc->stfle_fac_list)); + memcpy(lc->alt_stfle_fac_list, S390_lowcore.alt_stfle_fac_list, + sizeof(lc->alt_stfle_fac_list)); nmi_alloc_boot_cpu(lc); vdso_alloc_boot_cpu(lc); lc->sync_enter_timer = S390_lowcore.sync_enter_timer; diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c index a919b2f..fc28c95 100644 --- a/arch/s390/kernel/smp.c +++ b/arch/s390/kernel/smp.c @@ -266,7 +266,9 @@ static void pcpu_prepare_secondary(struct pcpu *pcpu, int cpu) __ctl_store(lc->cregs_save_area, 0, 15); save_access_regs((unsigned int *) lc->access_regs_save_area); memcpy(lc->stfle_fac_list, S390_lowcore.stfle_fac_list, - MAX_FACILITY_BIT/8); + sizeof(lc->stfle_fac_list)); + memcpy(lc->alt_stfle_fac_list, S390_lowcore.alt_stfle_fac_list, + sizeof(lc->alt_stfle_fac_list)); arch_spin_lock_setup(cpu); } -- 2.7.4