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

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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: Heiko Carstens <hca@linux.ibm.com>
This commit is contained in:
Heiko Carstens 2024-02-03 11:45:21 +01:00
parent 4ce69fcf17
commit 3a74f44de2
3 changed files with 20 additions and 16 deletions
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27
arch/s390/include/asm/checksum.h
View File

@ -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);
}
/*

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

@ -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;

6
arch/s390/kernel/os_info.c
View File

@ -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;