diff mbox series

[bpf-next,v3,1/1] libbpf: Fix ptr_is_aligned() usages

Message ID 20211021104658.624944-2-iii@linux.ibm.com (mailing list archive)
State Accepted
Commit 632f96d2652e0d4188de837f88a977eedb55aee1
Delegated to: BPF
Headers show
Series btf_dump fixes for s390 | expand

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netdev/fixes_present success Fixes tag not required for -next series
netdev/patch_count success Link
netdev/tree_selection success Clearly marked for bpf-next
netdev/subject_prefix success Link
netdev/cc_maintainers warning 7 maintainers not CCed: john.fastabend@gmail.com yhs@fb.com netdev@vger.kernel.org songliubraving@fb.com kafai@fb.com kpsingh@kernel.org andrii@kernel.org
netdev/source_inline success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/module_param success Was 0 now: 0
netdev/build_32bit success Errors and warnings before: 0 this patch: 0
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/verify_fixes success No Fixes tag
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 52 lines checked
netdev/build_allmodconfig_warn success Errors and warnings before: 0 this patch: 0
netdev/header_inline success No static functions without inline keyword in header files
bpf/vmtest-bpf-next-PR success PR summary
bpf/vmtest-bpf-next success VM_Test

Commit Message

Ilya Leoshkevich Oct. 21, 2021, 10:46 a.m. UTC 
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>
---
 tools/lib/bpf/btf_dump.c | 20 ++++++++++++--------
 1 file changed, 12 insertions(+), 8 deletions(-)
diff mbox series

Patch

diff --git a/tools/lib/bpf/btf_dump.c b/tools/lib/bpf/btf_dump.c
index e98c201f29b5..e9e5801ece4c 100644
--- a/tools/lib/bpf/btf_dump.c
+++ b/tools/lib/bpf/btf_dump.c
@@ -1657,9 +1657,15 @@  static int btf_dump_base_type_check_zero(struct btf_dump *d,
 	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,
@@ -1681,7 +1687,7 @@  static int btf_dump_int_data(struct btf_dump *d,
 	/* handle packed int data - accesses of integers not aligned on
 	 * 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);
 		data = buf;
 	}
@@ -1770,7 +1776,7 @@  static int btf_dump_float_data(struct btf_dump *d,
 	int sz = t->size;
 
 	/* 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);
 		flp = &fl;
 	}
@@ -1933,7 +1939,7 @@  static int btf_dump_ptr_data(struct btf_dump *d,
 			      __u32 id,
 			      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);
 	} else {
 		union ptr_data pt;
@@ -1953,10 +1959,8 @@  static int btf_dump_get_enum_value(struct btf_dump *d,
 				   __u32 id,
 				   __s64 *value)
 {
-	int sz = t->size;
-
 	/* handle unaligned enum value */
-	if (!ptr_is_aligned(data, sz)) {
+	if (!ptr_is_aligned(d->btf, id, data)) {
 		__u64 val;
 		int err;