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libbpf: Fix ptr_is_aligned() usages

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Currently ptr_is_aligned() takes size, and not alignment, as a
parameter, which may be overly pessimistic e.g. for __i128 on s390,
which must be only 8-byte aligned. Fix by using btf__align_of().

Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20211021104658.624944-2-iii@linux.ibm.com
This commit is contained in:
Ilya Leoshkevich
2021-10-21 12:46:58 +02:00
committed by Andrii Nakryiko
parent 19c6144c09
commit bde69b0ee0
1 changed files with 12 additions and 8 deletions
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20
src/btf_dump.c
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@@ -1657,9 +1657,15 @@ static int btf_dump_base_type_check_zero(struct btf_dump *d,
return 0; return 0;
} }
static bool ptr_is_aligned(const void *data, int data_sz) static bool ptr_is_aligned(const struct btf *btf, __u32 type_id,
const void *data)
{ {
return ((uintptr_t)data) % data_sz == 0; int alignment = btf__align_of(btf, type_id);
if (alignment == 0)
return false;
return ((uintptr_t)data) % alignment == 0;
} }
static int btf_dump_int_data(struct btf_dump *d, static int btf_dump_int_data(struct btf_dump *d,
@@ -1681,7 +1687,7 @@ static int btf_dump_int_data(struct btf_dump *d,
/* handle packed int data - accesses of integers not aligned on /* handle packed int data - accesses of integers not aligned on
* int boundaries can cause problems on some platforms. * int boundaries can cause problems on some platforms.
*/ */
if (!ptr_is_aligned(data, sz)) { if (!ptr_is_aligned(d->btf, type_id, data)) {
memcpy(buf, data, sz); memcpy(buf, data, sz);
data = buf; data = buf;
} }
@@ -1770,7 +1776,7 @@ static int btf_dump_float_data(struct btf_dump *d,
int sz = t->size; int sz = t->size;
/* handle unaligned data; copy to local union */ /* handle unaligned data; copy to local union */
if (!ptr_is_aligned(data, sz)) { if (!ptr_is_aligned(d->btf, type_id, data)) {
memcpy(&fl, data, sz); memcpy(&fl, data, sz);
flp = &fl; flp = &fl;
} }
@@ -1933,7 +1939,7 @@ static int btf_dump_ptr_data(struct btf_dump *d,
__u32 id, __u32 id,
const void *data) const void *data)
{ {
if (ptr_is_aligned(data, d->ptr_sz) && d->ptr_sz == sizeof(void *)) { if (ptr_is_aligned(d->btf, id, data) && d->ptr_sz == sizeof(void *)) {
btf_dump_type_values(d, "%p", *(void **)data); btf_dump_type_values(d, "%p", *(void **)data);
} else { } else {
union ptr_data pt; union ptr_data pt;
@@ -1953,10 +1959,8 @@ static int btf_dump_get_enum_value(struct btf_dump *d,
__u32 id, __u32 id,
__s64 *value) __s64 *value)
{ {
int sz = t->size;
/* handle unaligned enum value */ /* handle unaligned enum value */
if (!ptr_is_aligned(data, sz)) { if (!ptr_is_aligned(d->btf, id, data)) {
__u64 val; __u64 val;
int err; int err;