On 1/29/25 07:30, Helge Deller wrote:
Subject: [PATCH] target/hppa: Implement space register hashing for 64-bit HP-UX
The Linux kernel turns space-register hashing off unconditionally at
bootup. That code was provided by HP at the beginning of the PA-RISC
Linux porting effort, and I don't know why it was decided then why Linux
should not use space register hashing.
32-bit HP-UX versions seem to not use space register hashing either.
But for 64-bit HP-UX versions, Sven Schnelle noticed that space register
hashing needs to be enabled and is required, otherwise the HP-UX kernel
will crash badly.
On 64-bit CPUs space register hashing is controlled by a bit in diagnose
register %dr2. Since we want to support Linux and 32- and 64-bit HP-UX,
we need to fully emulate the diagnose registers and handle specifically
the bit in %dr2.
This patch adds the code to calculate the gva memory mask based on the
space-register hashing bit in %dr2 and the PSW_W (64-bit) flag.
The value is cached in the gva_offset_mask variable in CPUArchState
and recalculated at every modification of the CPU PSW or %dr2.
Signed-off-by: Helge Deller<[email protected]>
Suggested-by: Richard Henderson<[email protected]>
Suggested-by: Sven Schnelle<[email protected]>
Reviewed-by: Richard Henderson <[email protected]>
r~
