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s390/nmi: get rid of private slab cache

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Get rid of private "nmi_save_areas" slab cache. The only reason this was
introduced years ago was that with some slab debugging options allocations
would only guarantee a minimum alignment of ARCH_KMALLOC_MINALIGN, which
was eight bytes back then. This is not sufficient for the extended machine
check save area.

However since commit 59bb47985c ("mm, sl[aou]b: guarantee natural
alignment for kmalloc(power-of-two)") kmalloc guarantees a power-of-two
alignment even with debugging options enabled.

Therefore the private slab cache can be removed.

Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
This commit is contained in:
Heiko Carstens 2022-11-30 19:43:28 +01:00 committed by Alexander Gordeev
parent 742aed05af
commit bb3860cc02
1 changed files with 9 additions and 31 deletions
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40
arch/s390/kernel/nmi.c
View file

@ -42,21 +42,12 @@ struct mcck_struct {
};
static DEFINE_PER_CPU(struct mcck_struct, cpu_mcck);
static struct kmem_cache *mcesa_cache;
static unsigned long mcesa_origin_lc;
static inline int nmi_needs_mcesa(void)
{
return MACHINE_HAS_VX || MACHINE_HAS_GS;
}
static inline unsigned long nmi_get_mcesa_size(void)
{
if (MACHINE_HAS_GS)
return MCESA_MAX_SIZE;
return MCESA_MIN_SIZE;
}
/*
* The initial machine check extended save area for the boot CPU.
* It will be replaced on the boot CPU reinit with an allocated
@ -74,36 +65,23 @@ void __init nmi_alloc_mcesa_early(u64 *mcesad)
*mcesad |= ilog2(MCESA_MAX_SIZE);
}
static void __init nmi_alloc_cache(void)
int nmi_alloc_mcesa(u64 *mcesad)
{
unsigned long size;
if (!nmi_needs_mcesa())
return;
size = nmi_get_mcesa_size();
if (size > MCESA_MIN_SIZE)
mcesa_origin_lc = ilog2(size);
/* create slab cache for the machine-check-extended-save-areas */
mcesa_cache = kmem_cache_create("nmi_save_areas", size, size, 0, NULL);
if (!mcesa_cache)
panic("Couldn't create nmi save area cache");
}
int __ref nmi_alloc_mcesa(u64 *mcesad)
{
unsigned long origin;
void *origin;
*mcesad = 0;
if (!nmi_needs_mcesa())
return 0;
if (!mcesa_cache)
nmi_alloc_cache();
origin = (unsigned long) kmem_cache_alloc(mcesa_cache, GFP_KERNEL);
size = MACHINE_HAS_GS ? MCESA_MAX_SIZE : MCESA_MIN_SIZE;
origin = kmalloc(size, GFP_KERNEL);
if (!origin)
return -ENOMEM;
/* The pointer is stored with mcesa_bits ORed in */
kmemleak_not_leak((void *) origin);
*mcesad = __pa(origin) | mcesa_origin_lc;
kmemleak_not_leak(origin);
*mcesad = __pa(origin);
if (MACHINE_HAS_GS)
*mcesad |= ilog2(MCESA_MAX_SIZE);
return 0;
}
@ -111,7 +89,7 @@ void nmi_free_mcesa(u64 *mcesad)
{
if (!nmi_needs_mcesa())
return;
kmem_cache_free(mcesa_cache, __va(*mcesad & MCESA_ORIGIN_MASK));
kfree(__va(*mcesad & MCESA_ORIGIN_MASK));
}
static __always_inline char *nmi_puts(char *dest, const char *src)