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| author | Mitchell Horne <mhorne@FreeBSD.org> | 2024-01-17 16:45:41 +0000 |
|---|---|---|
| committer | Mitchell Horne <mhorne@FreeBSD.org> | 2024-01-18 17:20:42 +0000 |
| commit | 9c2e1a54f71a399fc4645c4b8bed044705629143 (patch) | |
| tree | ed9c67466d41555f76e5f7435a358a82261a4c56 | |
| parent | a2544cc8243f4136a912e08dbe86d8590d25a53d (diff) | |
| download | src-9c2e1a54f71a399fc4645c4b8bed044705629143.tar.gz src-9c2e1a54f71a399fc4645c4b8bed044705629143.zip | |
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
MFC after: 3 days
Fixes: a67687fcd8f5 ("Use native-sized accesses when accessing memory from kdb")
Differential Revision: https://reviews.freebsd.org/D43479
| -rw-r--r-- | sys/arm64/arm64/db_interface.c | 12 |
1 files changed, 9 insertions, 3 deletions
diff --git a/sys/arm64/arm64/db_interface.c b/sys/arm64/arm64/db_interface.c index 8d97ab46a837..0b1c58ca88a0 100644 --- a/sys/arm64/arm64/db_interface.c +++ b/sys/arm64/arm64/db_interface.c @@ -124,14 +124,20 @@ 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) |