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authorCédric Le Goater <clg@kaod.org>2019-10-31 07:31:00 +0100
committerMichael Ellerman <mpe@ellerman.id.au>2019-11-13 16:58:10 +1100
commit1ca3dec2b2dff9d286ce6cd64108bda0e98f9710 (patch)
tree6b42f60ef8f269333fc0db134fe89d274e720ce7 /arch/powerpc/sysdev
parent1db550f44ab672b5ded14a94e092b9a9a2d29c8c (diff)
powerpc/xive: Prevent page fault issues in the machine crash handler
When the machine crash handler is invoked, all interrupts are masked but interrupts which have not been started yet do not have an ESB page mapped in the Linux address space. This crashes the 'crash kexec' sequence on sPAPR guests. To fix, force the mapping of the ESB page when an interrupt is being mapped in the Linux IRQ number space. This is done by setting the initial state of the interrupt to OFF which is not necessarily the case on PowerNV. Fixes: 243e25112d06 ("powerpc/xive: Native exploitation of the XIVE interrupt controller") Cc: stable@vger.kernel.org # v4.12+ Signed-off-by: Cédric Le Goater <clg@kaod.org> Reviewed-by: Greg Kurz <groug@kaod.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20191031063100.3864-1-clg@kaod.org
Diffstat (limited to 'arch/powerpc/sysdev')
-rw-r--r--arch/powerpc/sysdev/xive/common.c9
1 files changed, 9 insertions, 0 deletions
diff --git a/arch/powerpc/sysdev/xive/common.c b/arch/powerpc/sysdev/xive/common.c
index df832b09e3e9..f5fadbd2533a 100644
--- a/arch/powerpc/sysdev/xive/common.c
+++ b/arch/powerpc/sysdev/xive/common.c
@@ -1035,6 +1035,15 @@ static int xive_irq_alloc_data(unsigned int virq, irq_hw_number_t hw)
xd->target = XIVE_INVALID_TARGET;
irq_set_handler_data(virq, xd);
+ /*
+ * Turn OFF by default the interrupt being mapped. A side
+ * effect of this check is the mapping the ESB page of the
+ * interrupt in the Linux address space. This prevents page
+ * fault issues in the crash handler which masks all
+ * interrupts.
+ */
+ xive_esb_read(xd, XIVE_ESB_SET_PQ_01);
+
return 0;
}