diff options
| author | Philippe Mathieu-Daudé <philmd@redhat.com> | 2019-07-15 14:17:03 +0100 |
|---|---|---|
| committer | Peter Maydell <peter.maydell@linaro.org> | 2019-07-15 14:17:03 +0100 |
| commit | c0bccee9b40ec58c9d165b406ae3d4f63652ce53 (patch) | |
| tree | aaf792340eece638dce1a5c3cd0cf3e09044ab18 | |
| parent | 526668c734e6a07f2fedfd378840a61b70c1cbab (diff) | |
hw/ssi/mss-spi: Avoid crash when reading empty RX FIFO
Reading the RX_DATA register when the RX_FIFO is empty triggers
an abort. This can be easily reproduced:
$ qemu-system-arm -M emcraft-sf2 -monitor stdio -S
QEMU 4.0.50 monitor - type 'help' for more information
(qemu) x 0x40001010
Aborted (core dumped)
(gdb) bt
#1 0x00007f035874f895 in abort () at /lib64/libc.so.6
#2 0x00005628686591ff in fifo8_pop (fifo=0x56286a9a4c68) at util/fifo8.c:66
#3 0x00005628683e0b8e in fifo32_pop (fifo=0x56286a9a4c68) at include/qemu/fifo32.h:137
#4 0x00005628683e0efb in spi_read (opaque=0x56286a9a4850, addr=4, size=4) at hw/ssi/mss-spi.c:168
#5 0x0000562867f96801 in memory_region_read_accessor (mr=0x56286a9a4b60, addr=16, value=0x7ffeecb0c5c8, size=4, shift=0, mask=4294967295, attrs=...) at memory.c:439
#6 0x0000562867f96cdb in access_with_adjusted_size (addr=16, value=0x7ffeecb0c5c8, size=4, access_size_min=1, access_size_max=4, access_fn=0x562867f967c3 <memory_region_read_accessor>, mr=0x56286a9a4b60, attrs=...) at memory.c:569
#7 0x0000562867f99940 in memory_region_dispatch_read1 (mr=0x56286a9a4b60, addr=16, pval=0x7ffeecb0c5c8, size=4, attrs=...) at memory.c:1420
#8 0x0000562867f99a08 in memory_region_dispatch_read (mr=0x56286a9a4b60, addr=16, pval=0x7ffeecb0c5c8, size=4, attrs=...) at memory.c:1447
#9 0x0000562867f38721 in flatview_read_continue (fv=0x56286aec6360, addr=1073745936, attrs=..., buf=0x7ffeecb0c7c0 "\340ǰ\354\376\177", len=4, addr1=16, l=4, mr=0x56286a9a4b60) at exec.c:3385
#10 0x0000562867f38874 in flatview_read (fv=0x56286aec6360, addr=1073745936, attrs=..., buf=0x7ffeecb0c7c0 "\340ǰ\354\376\177", len=4) at exec.c:3423
#11 0x0000562867f388ea in address_space_read_full (as=0x56286aa3e890, addr=1073745936, attrs=..., buf=0x7ffeecb0c7c0 "\340ǰ\354\376\177", len=4) at exec.c:3436
#12 0x0000562867f389c5 in address_space_rw (as=0x56286aa3e890, addr=1073745936, attrs=..., buf=0x7ffeecb0c7c0 "\340ǰ\354\376\177", len=4, is_write=false) at exec.c:3466
#13 0x0000562867f3bdd7 in cpu_memory_rw_debug (cpu=0x56286aa19d00, addr=1073745936, buf=0x7ffeecb0c7c0 "\340ǰ\354\376\177", len=4, is_write=0) at exec.c:3976
#14 0x000056286811ed51 in memory_dump (mon=0x56286a8c32d0, count=1, format=120, wsize=4, addr=1073745936, is_physical=0) at monitor/misc.c:730
#15 0x000056286811eff1 in hmp_memory_dump (mon=0x56286a8c32d0, qdict=0x56286b15c400) at monitor/misc.c:785
#16 0x00005628684740ee in handle_hmp_command (mon=0x56286a8c32d0, cmdline=0x56286a8caeb2 "0x40001010") at monitor/hmp.c:1082
From the datasheet "Actel SmartFusion Microcontroller Subsystem
User's Guide" Rev.1, Table 13-3 "SPI Register Summary", this
register has a reset value of 0.
Check the FIFO is not empty before accessing it, else log an
error message.
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-id: 20190709113715.7761-3-philmd@redhat.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
| -rw-r--r-- | hw/ssi/mss-spi.c | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/hw/ssi/mss-spi.c b/hw/ssi/mss-spi.c index 918b1f3e82..4c9da5d2b2 100644 --- a/hw/ssi/mss-spi.c +++ b/hw/ssi/mss-spi.c @@ -165,7 +165,13 @@ spi_read(void *opaque, hwaddr addr, unsigned int size) case R_SPI_RX: s->regs[R_SPI_STATUS] &= ~S_RXFIFOFUL; s->regs[R_SPI_STATUS] &= ~S_RXCHOVRF; - ret = fifo32_pop(&s->rx_fifo); + if (fifo32_is_empty(&s->rx_fifo)) { + qemu_log_mask(LOG_GUEST_ERROR, + "%s: Reading empty RX_FIFO\n", + __func__); + } else { + ret = fifo32_pop(&s->rx_fifo); + } if (fifo32_is_empty(&s->rx_fifo)) { s->regs[R_SPI_STATUS] |= S_RXFIFOEMP; } |