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s390/maccess: rework absolute lowcore accessors 

Macro mem_assign_absolute() is able to access the whole memory, but
is only used and makes sense when updating the absolute lowcore.
Instead, introduce get_abs_lowcore() and put_abs_lowcore() macros
that limit access to absolute lowcore addresses only.

Suggested-by: Heiko Carstens <hca@linux.ibm.com>
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
This commit is contained in:
Alexander Gordeev 2022-03-17 15:03:03 +01:00 committed by Vasily Gorbik
parent 9097fc793f
commit ed0192bc64
6 changed files with 32 additions and 24 deletions
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17
arch/s390/include/asm/processor.h
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@ -319,11 +319,18 @@ extern void (*s390_base_pgm_handler_fn)(struct pt_regs *regs);
extern int memcpy_real(void *, unsigned long, size_t);
extern void memcpy_absolute(void *, void *, size_t);
#define mem_assign_absolute(dest, val) do { \
__typeof__(dest) __tmp = (val); \
\
BUILD_BUG_ON(sizeof(__tmp) != sizeof(val)); \
memcpy_absolute(&(dest), &__tmp, sizeof(__tmp)); \
#define put_abs_lowcore(member, x) do { \
unsigned long __abs_address = offsetof(struct lowcore, member); \
__typeof__(((struct lowcore *)0)->member) __tmp = (x); \
\
memcpy_absolute(__va(__abs_address), &__tmp, sizeof(__tmp)); \
} while (0)
#define get_abs_lowcore(x, member) do { \
unsigned long __abs_address = offsetof(struct lowcore, member); \
__typeof__(((struct lowcore *)0)->member) *__ptr = &(x); \
\
memcpy_absolute(__ptr, __va(__abs_address), sizeof(*__ptr)); \
} while (0)
extern int s390_isolate_bp(void);

4
arch/s390/kernel/ipl.c
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@ -1646,8 +1646,8 @@ static void dump_reipl_run(struct shutdown_trigger *trigger)
csum = (__force unsigned int)
csum_partial(reipl_block_actual, reipl_block_actual->hdr.len, 0);
mem_assign_absolute(S390_lowcore.ipib, ipib);
mem_assign_absolute(S390_lowcore.ipib_checksum, csum);
put_abs_lowcore(ipib, ipib);
put_abs_lowcore(ipib_checksum, csum);
dump_run(trigger);
}

2
arch/s390/kernel/machine_kexec.c
View File

@ -226,7 +226,7 @@ void arch_crash_save_vmcoreinfo(void)
vmcoreinfo_append_str("SAMODE31=%lx\n", __samode31);
vmcoreinfo_append_str("EAMODE31=%lx\n", __eamode31);
vmcoreinfo_append_str("KERNELOFFSET=%lx\n", kaslr_offset());
mem_assign_absolute(S390_lowcore.vmcore_info, paddr_vmcoreinfo_note());
put_abs_lowcore(vmcore_info, paddr_vmcoreinfo_note());
}
void machine_shutdown(void)

2
arch/s390/kernel/os_info.c
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@ -63,7 +63,7 @@ void __init os_info_init(void)
os_info.version_minor = OS_INFO_VERSION_MINOR;
os_info.magic = OS_INFO_MAGIC;
os_info.csum = os_info_csum(&os_info);
mem_assign_absolute(S390_lowcore.os_info, __pa(ptr));
put_abs_lowcore(os_info, __pa(ptr));
}
#ifdef CONFIG_CRASH_DUMP

19
arch/s390/kernel/setup.c
View File

@ -481,11 +481,11 @@ static void __init setup_lowcore_dat_off(void)
lc->mcck_stack = mcck_stack + STACK_INIT_OFFSET;
/* Setup absolute zero lowcore */
mem_assign_absolute(S390_lowcore.restart_stack, lc->restart_stack);
mem_assign_absolute(S390_lowcore.restart_fn, lc->restart_fn);
mem_assign_absolute(S390_lowcore.restart_data, lc->restart_data);
mem_assign_absolute(S390_lowcore.restart_source, lc->restart_source);
mem_assign_absolute(S390_lowcore.restart_psw, lc->restart_psw);
put_abs_lowcore(restart_stack, lc->restart_stack);
put_abs_lowcore(restart_fn, lc->restart_fn);
put_abs_lowcore(restart_data, lc->restart_data);
put_abs_lowcore(restart_source, lc->restart_source);
put_abs_lowcore(restart_psw, lc->restart_psw);
lc->spinlock_lockval = arch_spin_lockval(0);
lc->spinlock_index = 0;
@ -501,6 +501,7 @@ static void __init setup_lowcore_dat_off(void)
static void __init setup_lowcore_dat_on(void)
{
struct lowcore *lc = lowcore_ptr[0];
int cr;
__ctl_clear_bit(0, 28);
S390_lowcore.external_new_psw.mask |= PSW_MASK_DAT;
@ -509,10 +510,10 @@ static void __init setup_lowcore_dat_on(void)
S390_lowcore.io_new_psw.mask |= PSW_MASK_DAT;
__ctl_store(S390_lowcore.cregs_save_area, 0, 15);
__ctl_set_bit(0, 28);
mem_assign_absolute(S390_lowcore.restart_flags, RESTART_FLAG_CTLREGS);
mem_assign_absolute(S390_lowcore.program_new_psw, lc->program_new_psw);
memcpy_absolute(&S390_lowcore.cregs_save_area, lc->cregs_save_area,
sizeof(S390_lowcore.cregs_save_area));
put_abs_lowcore(restart_flags, RESTART_FLAG_CTLREGS);
put_abs_lowcore(program_new_psw, lc->program_new_psw);
for (cr = 0; cr < ARRAY_SIZE(lc->cregs_save_area); cr++)
put_abs_lowcore(cregs_save_area[cr], lc->cregs_save_area[cr]);
}
static struct resource code_resource = {

12
arch/s390/kernel/smp.c
View File

@ -332,10 +332,10 @@ static void pcpu_delegate(struct pcpu *pcpu,
lc->restart_data = (unsigned long)data;
lc->restart_source = source_cpu;
} else {
mem_assign_absolute(lc->restart_stack, stack);
mem_assign_absolute(lc->restart_fn, (unsigned long)func);
mem_assign_absolute(lc->restart_data, (unsigned long)data);
mem_assign_absolute(lc->restart_source, source_cpu);
put_abs_lowcore(restart_stack, stack);
put_abs_lowcore(restart_fn, (unsigned long)func);
put_abs_lowcore(restart_data, (unsigned long)data);
put_abs_lowcore(restart_source, source_cpu);
}
__bpon();
asm volatile(
@ -591,9 +591,9 @@ void smp_ctl_set_clear_bit(int cr, int bit, bool set)
parms.andval = ~(1UL << bit);
}
spin_lock(&ctl_lock);
memcpy_absolute(&ctlreg, &S390_lowcore.cregs_save_area[cr], sizeof(ctlreg));
get_abs_lowcore(ctlreg, cregs_save_area[cr]);
ctlreg = (ctlreg & parms.andval) | parms.orval;
memcpy_absolute(&S390_lowcore.cregs_save_area[cr], &ctlreg, sizeof(ctlreg));
put_abs_lowcore(cregs_save_area[cr], ctlreg);
spin_unlock(&ctl_lock);
on_each_cpu(smp_ctl_bit_callback, &parms, 1);
}