starfive-tech/linux.git, branch rt-linux-release

cpupri: a work around for non-rt test panic

2023-11-06T11:36:13+00:00

kernel BUG at kernel/sched/cpupri.c:151! The same issue can be seen in link. https://www.spinics.net/lists/kernel/msg4184866.html Signed-off-by: Minda Chen

riscv: rt: add riscv lazy preempt support.

2023-11-06T11:36:10+00:00

The code is origin from arm64/x86 Signed-off-by: Minda Chen

config: add vf2 PREEMPT_RT and other config

2023-11-06T11:31:56+00:00

enable full preempt RT config. Set HZ 1000 and set no tickless Signed-off-by: Minda Chen

riscv: Allow riscv PREEMPT_RT config.

2023-11-06T11:25:49+00:00

RISCV allow to select RT Signed-off-by: minda.chen

POWERPC: Allow to enable RT

2023-11-06T11:24:53+00:00

Allow to select RT. Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Thomas Gleixner

powerpc/stackprotector: work around stack-guard init from atomic

2023-11-06T11:24:53+00:00

This is invoked from the secondary CPU in atomic context. On x86 we use tsc instead. On Power we XOR it against mftb() so lets use stack address as the initial value. Cc: stable-rt@vger.kernel.org Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Thomas Gleixner

powerpc/kvm: Disable in-kernel MPIC emulation for PREEMPT_RT

2023-11-06T11:24:53+00:00

While converting the openpic emulation code to use a raw_spinlock_t enables guests to run on RT, there's still a performance issue. For interrupts sent in directed delivery mode with a multiple CPU mask, the emulated openpic will loop through all of the VCPUs, and for each VCPUs, it call IRQ_check, which will loop through all the pending interrupts for that VCPU. This is done while holding the raw_lock, meaning that in all this time the interrupts and preemption are disabled on the host Linux. A malicious user app can max both these number and cause a DoS. This temporary fix is sent for two reasons. First is so that users who want to use the in-kernel MPIC emulation are aware of the potential latencies, thus making sure that the hardware MPIC and their usage scenario does not involve interrupts sent in directed delivery mode, and the number of possible pending interrupts is kept small. Secondly, this should incentivize the development of a proper openpic emulation that would be better suited for RT. Acked-by: Scott Wood Signed-off-by: Bogdan Purcareata Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Thomas Gleixner

powerpc/pseries/iommu: Use a locallock instead local_irq_save()

2023-11-06T11:24:52+00:00

The locallock protects the per-CPU variable tce_page. The function attempts to allocate memory while tce_page is protected (by disabling interrupts). Use local_irq_save() instead of local_irq_disable(). Cc: stable-rt@vger.kernel.org Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Thomas Gleixner

powerpc: traps: Use PREEMPT_RT

2023-11-06T11:24:52+00:00

Add PREEMPT_RT to the backtrace if enabled. Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Thomas Gleixner

ARM: Allow to enable RT

2023-11-06T11:24:52+00:00

Allow to select RT. Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Thomas Gleixner