From 17328f218fb760c9c6accc5b52494889243a6b98 Mon Sep 17 00:00:00 2001 From: Frederic Barrat Date: Mon, 13 Jan 2020 14:01:18 +0100 Subject: [PATCH] powerpc/xive: Discard ESB load value when interrupt is invalid MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit A load on an ESB page returning all 1's means that the underlying device has invalidated the access to the PQ state of the interrupt through mmio. It may happen, for example when querying a PHB interrupt while the PHB is in an error state. In that case, we should consider the interrupt to be invalid when checking its state in the irq_get_irqchip_state() handler. Fixes: da15c03b047d ("powerpc/xive: Implement get_irqchip_state method for XIVE to fix shutdown race") Cc: stable@vger.kernel.org # v5.4+ Signed-off-by: Frederic Barrat [clg: wrote a commit log, introduced XIVE_ESB_INVALID ] Signed-off-by: Cédric Le Goater Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20200113130118.27969-1-clg@kaod.org --- arch/powerpc/include/asm/xive-regs.h | 1 + arch/powerpc/sysdev/xive/common.c | 15 ++++++++++++--- 2 files changed, 13 insertions(+), 3 deletions(-) diff --git a/arch/powerpc/include/asm/xive-regs.h b/arch/powerpc/include/asm/xive-regs.h index f2dfcd50a2d3..33aee7490cbb 100644 --- a/arch/powerpc/include/asm/xive-regs.h +++ b/arch/powerpc/include/asm/xive-regs.h @@ -39,6 +39,7 @@ #define XIVE_ESB_VAL_P 0x2 #define XIVE_ESB_VAL_Q 0x1 +#define XIVE_ESB_INVALID 0xFF /* * Thread Management (aka "TM") registers diff --git a/arch/powerpc/sysdev/xive/common.c b/arch/powerpc/sysdev/xive/common.c index f5fadbd2533a..9651ca061828 100644 --- a/arch/powerpc/sysdev/xive/common.c +++ b/arch/powerpc/sysdev/xive/common.c @@ -972,12 +972,21 @@ static int xive_get_irqchip_state(struct irq_data *data, enum irqchip_irq_state which, bool *state) { struct xive_irq_data *xd = irq_data_get_irq_handler_data(data); + u8 pq; switch (which) { case IRQCHIP_STATE_ACTIVE: - *state = !xd->stale_p && - (xd->saved_p || - !!(xive_esb_read(xd, XIVE_ESB_GET) & XIVE_ESB_VAL_P)); + pq = xive_esb_read(xd, XIVE_ESB_GET); + + /* + * The esb value being all 1's means we couldn't get + * the PQ state of the interrupt through mmio. It may + * happen, for example when querying a PHB interrupt + * while the PHB is in an error state. We consider the + * interrupt to be inactive in that case. + */ + *state = (pq != XIVE_ESB_INVALID) && !xd->stale_p && + (xd->saved_p || !!(pq & XIVE_ESB_VAL_P)); return 0; default: return -EINVAL;