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

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[ 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>
This commit is contained in:
Martin Schwidefsky 2018-04-27 07:36:50 +02:00 committed by Greg Kroah-Hartman
parent cf6bc919fa
commit bc650e567c
6 changed files with 31 additions and 4 deletions
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18
arch/s390/include/asm/facility.h
View File

@ -13,6 +13,24 @@
#define MAX_FACILITY_BIT (256*8) /* stfle_fac_list has 256 bytes */
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;

3
arch/s390/include/asm/lowcore.h
View File

@ -170,7 +170,8 @@ 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 vector register save area */

3
arch/s390/kernel/alternative.c
View File

@ -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)) {

3
arch/s390/kernel/early.c
View File

@ -279,6 +279,9 @@ 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)

4
arch/s390/kernel/setup.c
View File

@ -334,7 +334,9 @@ static void __init setup_lowcore(void)
lc->machine_flags = S390_lowcore.machine_flags;
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)
lc->vector_save_area_addr =
(unsigned long) &lc->vector_save_area;

4
arch/s390/kernel/smp.c
View File

@ -250,7 +250,9 @@ 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)