This is a note to let you know that I've just added the patch titled mailbox: pcc: Handle all PCC subtypes correctly in pcc_mbox_irq to the 5.16-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: mailbox-pcc-handle-all-pcc-subtypes-correctly-in-pcc.patch and it can be found in the queue-5.16 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit b1008eaae7f1b5192837f67ac6165535050beb8d Author: Sudeep Holla <sudeep.holla@xxxxxxx> Date: Thu Dec 9 09:21:46 2021 +0000 mailbox: pcc: Handle all PCC subtypes correctly in pcc_mbox_irq [ Upstream commit 7215a7857e796c655ae1184b313556102fa8bc40 ] Commit c45ded7e1135 ("mailbox: pcc: Add support for PCCT extended PCC subspaces(type 3/4)") enabled the type3/4 of PCCT, but the change in pcc_mbox_irq breaks the other PCC subtypes. The kernel reports a warning on an Ampere eMag server -->8 CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.16.0-rc4 #127 Hardware name: MiTAC RAPTOR EV-883832-X3-0001/RAPTOR, BIOS 0.14 02/22/2019 Call trace: dump_backtrace+0x0/0x200 show_stack+0x20/0x30 dump_stack_lvl+0x68/0x84 dump_stack+0x18/0x34 __report_bad_irq+0x54/0x17c note_interrupt+0x330/0x428 handle_irq_event_percpu+0x90/0x98 handle_irq_event+0x4c/0x148 handle_fasteoi_irq+0xc4/0x188 generic_handle_domain_irq+0x44/0x68 gic_handle_irq+0x84/0x2ec call_on_irq_stack+0x28/0x34 do_interrupt_handler+0x88/0x90 el1_interrupt+0x48/0xb0 el1h_64_irq_handler+0x18/0x28 el1h_64_irq+0x7c/0x80 Fixes: c45ded7e1135 ("mailbox: pcc: Add support for PCCT extended PCC subspaces(type 3/4)") Reported-by: Justin He <justin.he@xxxxxxx> Tested-by: Justin He <justin.he@xxxxxxx> Signed-off-by: Sudeep Holla <sudeep.holla@xxxxxxx> Signed-off-by: Jassi Brar <jaswinder.singh@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/mailbox/pcc.c b/drivers/mailbox/pcc.c index e0a1ab3861f0d..ed18936b8ce68 100644 --- a/drivers/mailbox/pcc.c +++ b/drivers/mailbox/pcc.c @@ -241,9 +241,11 @@ static irqreturn_t pcc_mbox_irq(int irq, void *p) if (ret) return IRQ_NONE; - val &= pchan->cmd_complete.status_mask; - if (!val) - return IRQ_NONE; + if (val) { /* Ensure GAS exists and value is non-zero */ + val &= pchan->cmd_complete.status_mask; + if (!val) + return IRQ_NONE; + } ret = pcc_chan_reg_read(&pchan->error, &val); if (ret)