s390/alternative: use a copy of the facility bit mask

[ Upstream commit cf1489984641369611556bf00c48f945c77bcf02 ]

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 <david@redhat.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/arch/s390/include/asm/facility.h b/arch/s390/include/asm/facility.h
index f040644..2d58478 100644 (file)
--- 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 917f734..26d742f 100644 (file)
--- a/arch/s390/include/asm/lowcore.h
+++ b/arch/s390/include/asm/lowcore.h
@@ -155,7 +155,8 @@ 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 315986a..f5060af 100644 (file)
--- a/arch/s390/kernel/alternative.c
+++ b/arch/s390/kernel/alternative.c
@@ -74,7 +74,8 @@ 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 f7b280f..901d62e 100644 (file)
--- a/arch/s390/kernel/early.c
+++ b/arch/s390/kernel/early.c
@@ -329,6 +329,9 @@ 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 c6d2d54..a9f0516 100644 (file)
--- a/arch/s390/kernel/setup.c
+++ b/arch/s390/kernel/setup.c
@@ -339,7 +339,9 @@ 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));
        if (MACHINE_HAS_VX || MACHINE_HAS_GS) {
                unsigned long bits, size;
 

diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c
index 7ffaf9f..e906b77 100644 (file)
--- a/arch/s390/kernel/smp.c
+++ b/arch/s390/kernel/smp.c
@@ -282,7 +282,9 @@ 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));
 }
 
 static void pcpu_attach_task(struct pcpu *pcpu, struct task_struct *tsk)