Commit 3a74f44d authored by Heiko Carstens's avatar Heiko Carstens
Browse files

s390/checksum: provide and use cksm() inline assembly 



Convert those callers of csum_partial() to use the cksm instruction,
which are either very early or in critical paths, like panic/dump, so
they don't have to rely on a working kernel infrastructure, which will
be introduced with a subsequent patch.

Signed-off-by: default avatarHeiko Carstens <hca@linux.ibm.com>
parent 4ce69fcf

arch/s390/include/asm/checksum.h

+16 −11
Original line number Diff line number Diff line
@@ -15,6 +15,21 @@ 
#include <linux/instrumented.h>

#include <linux/in6.h>



static inline __wsum cksm(const void *buff, int len, __wsum sum)

{

	union register_pair rp = {

		.even = (unsigned long)buff,

		.odd = (unsigned long)len,

	};



	instrument_read(buff, len);

	asm volatile("\n"

		"0:	cksm	%[sum],%[rp]\n"

		"	jo	0b\n"

		: [sum] "+&d" (sum), [rp] "+&d" (rp.pair) : : "cc", "memory");

	return sum;

}



/*

 * Computes the checksum of a memory block at buff, length len,

 * and adds in "sum" (32-bit).
@@ -29,17 +44,7 @@ 
 */

static inline __wsum csum_partial(const void *buff, int len, __wsum sum)

{

	union register_pair rp = {

		.even = (unsigned long) buff,

		.odd = (unsigned long) len,

	};



	instrument_read(buff, len);

	asm volatile(

		"0:	cksm	%[sum],%[rp]\n"

		"	jo	0b\n"

		: [sum] "+&d" (sum), [rp] "+&d" (rp.pair) : : "cc", "memory");

	return sum;

	return cksm(buff, len, sum);

}



/*

arch/s390/kernel/ipl.c

+1 −2
Original line number Diff line number Diff line
@@ -1941,8 +1941,7 @@ static void dump_reipl_run(struct shutdown_trigger *trigger) 
	    reipl_type == IPL_TYPE_UNKNOWN)

		os_info_flags |= OS_INFO_FLAG_REIPL_CLEAR;

	os_info_entry_add(OS_INFO_FLAGS_ENTRY, &os_info_flags, sizeof(os_info_flags));

	csum = (__force unsigned int)

	       csum_partial(reipl_block_actual, reipl_block_actual->hdr.len, 0);

	csum = (__force unsigned int)cksm(reipl_block_actual, reipl_block_actual->hdr.len, 0);

	abs_lc = get_abs_lowcore();

	abs_lc->ipib = __pa(reipl_block_actual);

	abs_lc->ipib_checksum = csum;

arch/s390/kernel/os_info.c

+3 −3
Original line number Diff line number Diff line
@@ -29,7 +29,7 @@ static struct os_info os_info __page_aligned_data; 
u32 os_info_csum(struct os_info *os_info)

{

	int size = sizeof(*os_info) - offsetof(struct os_info, version_major);

	return (__force u32)csum_partial(&os_info->version_major, size, 0);

	return (__force u32)cksm(&os_info->version_major, size, 0);

}



/*
@@ -49,7 +49,7 @@ void os_info_entry_add(int nr, void *ptr, u64 size) 
{

	os_info.entry[nr].addr = __pa(ptr);

	os_info.entry[nr].size = size;

	os_info.entry[nr].csum = (__force u32)csum_partial(ptr, size, 0);

	os_info.entry[nr].csum = (__force u32)cksm(ptr, size, 0);

	os_info.csum = os_info_csum(&os_info);

}
@@ -98,7 +98,7 @@ static void os_info_old_alloc(int nr, int align) 
		msg = "copy failed";

		goto fail_free;

	}

	csum = (__force u32)csum_partial(buf_align, size, 0);

	csum = (__force u32)cksm(buf_align, size, 0);

	if (csum != os_info_old->entry[nr].csum) {

		msg = "checksum failed";

		goto fail_free;