diff options
| author | kamil <kamil@NetBSD.org> | 2018-05-30 17:31:34 +0000 |
|---|---|---|
| committer | kamil <kamil@NetBSD.org> | 2018-05-30 17:31:34 +0000 |
| commit | ca6ad33a9855119a058a070fb46daeaeb6f91155 (patch) | |
| tree | c1de9e147fe68146eb298d269c6c43ac95e73d75 /sys/dev/microcode/tools | |
| parent | ee9284b3760b1356dfe874b7ea49091ee6c7edc0 (diff) | |
Make the trigger_bus() test compatible with more CPUs (at least ALPHA)
If we write a byte character into a pointer, a compiler can emit a
read-modify-write operation, especially when a CPU cannot access directly
a character wide address.
In this scenario calling mmap(2) with PROT_WRITE, without PROT_READ will
emit unexpected trap.
There are two possible workarounds for this issue:
- write register wide memory without rmw sequence,
- mark the region with additional protection PROT_READ
Both work for NetBSD/alpha.
Go for the latter as perhaps more safe for dump compilers emitting rmw
sequences.
Investigated by <martin>
Diffstat (limited to 'sys/dev/microcode/tools')
0 files changed, 0 insertions, 0 deletions
