Commit bb3860cc authored by Heiko Carstens's avatar Heiko Carstens Committed by Alexander Gordeev
Browse files

s390/nmi: get rid of private slab cache 



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 59bb4798 ("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: default avatarAlexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: default avatarHeiko Carstens <hca@linux.ibm.com>
Signed-off-by: default avatarAlexander Gordeev <agordeev@linux.ibm.com>
parent 742aed05

arch/s390/kernel/nmi.c

+9 −31
Original line number Diff line number Diff line
@@ -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)