From: Helge Deller deller@gmx.de
commit 527a1d1ede98479bf90c31a64822107ac7e6d276 upstream.
According to the found documentation, data cache flushes and sync instructions are needed on the PCX-U+ (PA8200, e.g. C200/C240) platforms, while PCX-W (PA8500, e.g. C360) platforms aparently don't need those flushes when changing the IO PDIR data structures.
We have no documentation for PCX-W+ (PA8600) and PCX-W2 (PA8700) CPUs, but Carlo Pisani reported that his C3600 machine (PA8600, PCX-W+) fails when the fdc instructions were removed. His firmware didn't set the NIOP bit, so one may assume it's a firmware bug since other C3750 machines had the bit set.
Even if documentation (as mentioned above) states that PCX-W (PA8500, e.g. J5000) does not need fdc flushes, Sven could show that an Adaptec 29320A PCI-X SCSI controller reliably failed on a dd command during the first five minutes in his J5000 when fdc flushes were missing.
Going forward, we will now NOT replace the fdc and sync assembler instructions by NOPS if: a) the NP iopdir_fdc bit was set by firmware, or b) we find a CPU up to and including a PCX-W+ (PA8600).
This fixes the HPMC crashes on a C240 and C36XX machines. For other machines we rely on the firmware to set the bit when needed.
In case one finds HPMC issues, people could try to boot their machines with the "no-alternatives" kernel option to turn off any alternative patching.
Reported-by: Sven Schnelle svens@stackframe.org Reported-by: Carlo Pisani carlojpisani@gmail.com Tested-by: Sven Schnelle svens@stackframe.org Fixes: 3847dab77421 ("parisc: Add alternative coding infrastructure") Signed-off-by: Helge Deller deller@gmx.de Cc: stable@vger.kernel.org # 5.0+ Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- arch/parisc/kernel/alternative.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
--- a/arch/parisc/kernel/alternative.c +++ b/arch/parisc/kernel/alternative.c @@ -56,7 +56,8 @@ void __init_or_module apply_alternatives * time IO-PDIR is changed in Ike/Astro. */ if ((cond & ALT_COND_NO_IOC_FDC) && - (boot_cpu_data.pdc.capabilities & PDC_MODEL_IOPDIR_FDC)) + ((boot_cpu_data.cpu_type <= pcxw_) || + (boot_cpu_data.pdc.capabilities & PDC_MODEL_IOPDIR_FDC))) continue;
/* Want to replace pdtlb by a pdtlb,l instruction? */