From: Peter Delevoryas <pdel@fb.com>

Hey everyone,

I think there might be a bug aspeed_gpio_update, when it's selecting a
GPIO IRQ to update. I was testing booting Facebook's OpenBMC platform
"YosemiteV2" (fby2), and I was hitting a segfault in QEMU:

qemu-system-arm -machine ast2500-evb \
    -drive file=fby2.mtd,format=raw,if=mtd \
    -serial stdio -display none
...
Setup Caching for Bridge IC info..done.
Setup Front Panel Daemon..done.
Setup fan speed...
FAN CONFIG : Single Rotor FAN
Unexpected 4 Servers config! Run FSC 4 TLs Config as default config
Setting Zone 0 speed to 70%
Setting Zone 1 speed to 70%
ok: run: fscd: (pid 1726) 0s
done.
Powering fru 1 to ON state...
Segmentation fault (core dumped)

In gdb:

Thread 3 "qemu-system-arm" received signal SIGSEGV, Segmentation fault.
[Switching to Thread 0x7ffff20ee700 (LWP 1840353)]
qemu_set_irq (irq=0xffffffff00000000, level=1) at ../hw/core/irq.c:45
45          irq->handler(irq->opaque, irq->n, level);
(gdb) p irq
$1 = (qemu_irq) 0xffffffff00000000
(gdb) up
#1  0x00005555558e36f5 in aspeed_gpio_update (s=0x7ffff7ecffb0, regs=0x7ffff7ed0c94, value=128) at ../hw/gpio/aspeed_gpio.c:287
287                     qemu_set_irq(s->gpios[offset], !!(new & mask));
(gdb) p s->gpios
$2 = {0x0 <repeats 228 times>}
(gdb) p offset
$3 = 231
(gdb) p set
$5 = 7
(gdb) p gpio
$4 = 7

The commit message for the fix has a little more info on the bug here,
see that for more info.

I tested this by verifying that after this diff, I can boot this fby2
platform. I don't see any unit or qtest's for aspeed gpio's, maybe I
could add one? I figured that, first, I could just put out an email to
let everyone know about it, and get the diff reviewed.

The image I was using is here:

https://github.com/peterdelevoryas/openbmc/releases/tag/fby2.debug.mtd

Peter Delevoryas (1):
  hw: aspeed_gpio: Fix GPIO array indexing

 hw/gpio/aspeed_gpio.c         | 80 +++++++++++++++--------------------
 include/hw/gpio/aspeed_gpio.h |  5 +--
 2 files changed, 35 insertions(+), 50 deletions(-)

-- 
2.30.2