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On pre-r6 systems with the MT ASE the CPS SMP code included checks to halt the VPE running mips_cps_boot_vpes() if its bit in the struct core_boot_config vpe_mask field is clear. This was largely done in order to allow us to start arbitrary VPEs within a core despite the fact that hardware is typically configured to run only VPE0 after powering up a core. VPE0 would start the desired other VPEs, halt itself, and the fact that VPE0 started would be largely hidden & irrelevant. In MIPSr6 multithreading we have control over which VPs start executing when a core powers up via the cores CPC registers accessed remotely through the redirect block. For this reason the MIPSr6 multithreading path in mips_cps_boot_vpes() hasn't bothered up until now to handle halting the VP running it. However it is possible to power up cores entirely in hardware by using a pwr_up pin associated with the core. Unfortunately some systems wire this pin to a logic 1, which means that it is possible for a core to power up at a point that software doesn't expect. The result is that we generally go execute the kernel on a CPU that ought not to be running & the results can be unpredictable. Handle this case by stopping VPs that we don't expect to be running in mips_cps_boot_vpes() - with this change even if a core powers up it will do nothing useful & all VPs within it will stop running before they proceed to run general kernel code & do any damage. Ideally we would produce some sort of warning here, but given the stage of core bringup this happens at that would be non-trivial. We also will only hit this if a core starts up after being offlined via hotplug, and when that happens we will already produce a warning that the CPU didn't power down in cps_cpu_die() which seems sufficient. Signed-off-by: Paul Burton <paul.burton@imgtec.com> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/16198/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org> |
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| alchemy | ||
| ar7 | ||
| ath25 | ||
| ath79 | ||
| bcm47xx | ||
| bcm63xx | ||
| bmips | ||
| boot | ||
| cavium-octeon | ||
| cobalt | ||
| configs | ||
| dec | ||
| emma | ||
| fw | ||
| generic | ||
| include | ||
| jazz | ||
| jz4740 | ||
| kernel | ||
| kvm | ||
| lantiq | ||
| lasat | ||
| lib | ||
| loongson32 | ||
| loongson64 | ||
| math-emu | ||
| mm | ||
| mti-malta | ||
| net | ||
| netlogic | ||
| oprofile | ||
| paravirt | ||
| pci | ||
| pic32 | ||
| pistachio | ||
| pmcs-msp71xx | ||
| pnx833x | ||
| power | ||
| ralink | ||
| rb532 | ||
| sgi-ip22 | ||
| sgi-ip27 | ||
| sgi-ip32 | ||
| sibyte | ||
| sni | ||
| txx9 | ||
| vdso | ||
| vr41xx | ||
| xilfpga | ||
| Kbuild | ||
| Kbuild.platforms | ||
| Kconfig | ||
| Kconfig.debug | ||
| Makefile | ||
| Makefile.postlink | ||