[PATCH 5.4 147/177] powerpc/xive: Skip ioremap() of ESB pages for LSI interrupts

Greg Kroah-Hartman
2019-12-16T18:20:25Z

From: Cédric Le Goater <clg@kaod.org>

commit b67a95f2abff0c34e5667c15ab8900de73d8d087 upstream.

The PCI INTx interrupts and other LSI interrupts are handled differently
under a sPAPR platform. When the interrupt source characteristics are
queried, the hypervisor returns an H_INT_ESB flag to inform the OS
that it should be using the H_INT_ESB hcall for interrupt management
and not loads and stores on the interrupt ESB pages.

A default -1 value is returned for the addresses of the ESB pages. The
driver ignores this condition today and performs a bogus IO mapping.
Recent changes and the DEBUG_VM configuration option make the bug
visible with :

kernel BUG at arch/powerpc/include/asm/book3s/64/pgtable.h:612!
Oops: Exception in kernel mode, sig: 5 [#1]
LE PAGE_SIZE=64K MMU=Radix MMU=Hash SMP NR_CPUS=1024 NUMA pSeries
Modules linked in:
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.4.0-0.rc6.git0.1.fc32.ppc64le #1
NIP: c000000000f63294 LR: c000000000f62e44 CTR: 0000000000000000
REGS: c0000000fa45f0d0 TRAP: 0700 Not tainted (5.4.0-0.rc6.git0.1.fc32.ppc64le)
...
NIP ioremap_page_range+0x4c4/0x6e0
LR ioremap_page_range+0x74/0x6e0
Call Trace:
ioremap_page_range+0x74/0x6e0 (unreliable)
do_ioremap+0x8c/0x120
__ioremap_caller+0x128/0x140
ioremap+0x30/0x50
xive_spapr_populate_irq_data+0x170/0x260
xive_irq_domain_map+0x8c/0x170
irq_domain_associate+0xb4/0x2d0
irq_create_mapping+0x1e0/0x3b0
irq_create_fwspec_mapping+0x27c/0x3e0
irq_create_of_mapping+0x98/0xb0
of_irq_parse_and_map_pci+0x168/0x230
pcibios_setup_device+0x88/0x250
pcibios_setup_bus_devices+0x54/0x100
__of_scan_bus+0x160/0x310
pcibios_scan_phb+0x330/0x390
pcibios_init+0x8c/0x128
do_one_initcall+0x60/0x2c0
kernel_init_freeable+0x290/0x378
kernel_init+0x2c/0x148
ret_from_kernel_thread+0x5c/0x80

Fixes: bed81ee181dd ("powerpc/xive: introduce H_INT_ESB hcall")
Cc: stable@vger.kernel.org # v4.14+
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Tested-by: Daniel Axtens <dja@axtens.net>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20191203163642.2428-1-clg@kaod.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
arch/powerpc/sysdev/xive/spapr.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)

--- a/arch/powerpc/sysdev/xive/spapr.c
+++ b/arch/powerpc/sysdev/xive/spapr.c
@@ -392,20 +392,28 @@ static int xive_spapr_populate_irq_data(
data->esb_shift = esb_shift;
data->trig_page = trig_page;

+ data->hw_irq = hw_irq;
+
/*
* No chip-id for the sPAPR backend. This has an impact how we
* pick a target. See xive_pick_irq_target().
*/
data->src_chip = XIVE_INVALID_CHIP_ID;

+ /*
+ * When the H_INT_ESB flag is set, the H_INT_ESB hcall should
+ * be used for interrupt management. Skip the remapping of the
+ * ESB pages which are not available.
+ */
+ if (data->flags & XIVE_IRQ_FLAG_H_INT_ESB)
+ return 0;
+
data->eoi_mmio = ioremap(data->eoi_page, 1u << data->esb_shift);
if (!data->eoi_mmio) {
pr_err("Failed to map EOI page for irq 0x%x\n", hw_irq);
return -ENOMEM;
}

- data->hw_irq = hw_irq;
-
/* Full function page supports trigger */
if (flags & XIVE_SRC_TRIGGER) {
data->trig_mmio = data->eoi_mmio;