The branch stable/13 has been updated by mhorne:
URL:
https://cgit.FreeBSD.org/src/commit/?id=4057fb12a1d7147b85062ad9f3916138c3956cf3
commit 4057fb12a1d7147b85062ad9f3916138c3956cf3
Author: Mitchell Horne <mho...@freebsd.org>
AuthorDate: 2024-01-17 16:45:41 +0000
Commit: Mitchell Horne <mho...@freebsd.org>
CommitDate: 2024-01-22 18:05:27 +0000
arm64: fix db_read_bytes() for size == 8
There is a mistake in the cast, resulting in a truncated read to tmp64.
Switch from int to uint64_t, and adjust the other casts for clarity.
Add a comment explaining why we do this at all.
Reported by: dfr
Reviewed by: dfr, mmel, emaste, jhb (all a previous version)
PR: 276406
Fixes: a67687fcd8f5 ("Use native-sized accesses when accessing
memory from kdb")
Differential Revision: https://reviews.freebsd.org/D43479
(cherry picked from commit 9c2e1a54f71a399fc4645c4b8bed044705629143)
---
sys/arm64/arm64/db_interface.c | 12 +++++++++---
1 file changed, 9 insertions(+), 3 deletions(-)
diff --git a/sys/arm64/arm64/db_interface.c b/sys/arm64/arm64/db_interface.c
index 0c369ba87709..65af5395500e 100644
--- a/sys/arm64/arm64/db_interface.c
+++ b/sys/arm64/arm64/db_interface.c
@@ -125,14 +125,20 @@ db_read_bytes(vm_offset_t addr, size_t size, char *data)
if (ret == 0) {
src = (const char *)addr;
+
+ /*
+ * Perform a native-sized memory access, if possible. This
+ * enables reading from MMIO devices that don't support single
+ * byte access.
+ */
if (size == 8 && (addr & 7) == 0) {
- tmp64 = *((const int *)src);
+ tmp64 = *((const uint64_t *)src);
src = (const char *)&tmp64;
} else if (size == 4 && (addr & 3) == 0) {
- tmp32 = *((const int *)src);
+ tmp32 = *((const uint32_t *)src);
src = (const char *)&tmp32;
} else if (size == 2 && (addr & 1) == 0) {
- tmp16 = *((const short *)src);
+ tmp16 = *((const uint16_t *)src);
src = (const char *)&tmp16;
}
while (size-- > 0)
