Since commit 5ec3a23e6c8 ("serial: convert PIO to new memory
api read/write") we don't need to worry about accesses bigger
than 8-bit. Use the extract()/deposit() functions to access
the correct part of the 16-bit 'divider' register.
Reported-by: Jonathan D. Belanger <jbelanger1@rochester.rr.com>
Buglink: https://bugs.launchpad.net/qemu/+bug/1904331
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
---
Cc: Bug 1904331 <1904331@bugs.launchpad.net>
---
hw/char/serial.c | 13 +++++--------
1 file changed, 5 insertions(+), 8 deletions(-)
diff --git a/hw/char/serial.c b/hw/char/serial.c
index 97f71879ff2..62c627f486f 100644
--- a/hw/char/serial.c
+++ b/hw/char/serial.c
@@ -24,6 +24,7 @@
*/
#include "qemu/osdep.h"
+#include "qemu/bitops.h"
#include "hw/char/serial.h"
#include "hw/irq.h"
#include "migration/vmstate.h"
@@ -338,11 +339,7 @@ static void serial_ioport_write(void *opaque, hwaddr addr, uint64_t val,
default:
case 0:
if (s->lcr & UART_LCR_DLAB) {
- if (size == 1) {
- s->divider = (s->divider & 0xff00) | val;
- } else {
- s->divider = val;
- }
+ s->divider = deposit32(s->divider, 8 * addr, 8, val);
serial_update_parameters(s);
} else {
s->thr = (uint8_t) val;
@@ -364,7 +361,7 @@ static void serial_ioport_write(void *opaque, hwaddr addr, uint64_t val,
break;
case 1:
if (s->lcr & UART_LCR_DLAB) {
- s->divider = (s->divider & 0x00ff) | (val << 8);
+ s->divider = deposit32(s->divider, 8 * addr, 8, val);
serial_update_parameters(s);
} else {
uint8_t changed = (s->ier ^ val) & 0x0f;
@@ -478,7 +475,7 @@ static uint64_t serial_ioport_read(void *opaque, hwaddr addr, unsigned size)
default:
case 0:
if (s->lcr & UART_LCR_DLAB) {
- ret = s->divider & 0xff;
+ ret = extract16(s->divider, 8 * addr, 8);
} else {
if(s->fcr & UART_FCR_FE) {
ret = fifo8_is_empty(&s->recv_fifo) ?
@@ -502,7 +499,7 @@ static uint64_t serial_ioport_read(void *opaque, hwaddr addr, unsigned size)
break;
case 1:
if (s->lcr & UART_LCR_DLAB) {
- ret = (s->divider >> 8) & 0xff;
+ ret = extract16(s->divider, 8 * addr, 8);
} else {
ret = s->ier;
}
--
2.26.2
On 20/11/20 17:19, Philippe Mathieu-Daudé wrote: > Since commit 5ec3a23e6c8 ("serial: convert PIO to new memory > api read/write") we don't need to worry about accesses bigger > than 8-bit. Use the extract()/deposit() functions to access > the correct part of the 16-bit 'divider' register. > > Reported-by: Jonathan D. Belanger <jbelanger1@rochester.rr.com> > Buglink: https://bugs.launchpad.net/qemu/+bug/1904331 > Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org> > --- > Cc: Bug 1904331 <1904331@bugs.launchpad.net> > --- > hw/char/serial.c | 13 +++++-------- > 1 file changed, 5 insertions(+), 8 deletions(-) Looks good, but certainly not for 5.2. Paolo > diff --git a/hw/char/serial.c b/hw/char/serial.c > index 97f71879ff2..62c627f486f 100644 > --- a/hw/char/serial.c > +++ b/hw/char/serial.c > @@ -24,6 +24,7 @@ > */ > > #include "qemu/osdep.h" > +#include "qemu/bitops.h" > #include "hw/char/serial.h" > #include "hw/irq.h" > #include "migration/vmstate.h" > @@ -338,11 +339,7 @@ static void serial_ioport_write(void *opaque, hwaddr addr, uint64_t val, > default: > case 0: > if (s->lcr & UART_LCR_DLAB) { > - if (size == 1) { > - s->divider = (s->divider & 0xff00) | val; > - } else { > - s->divider = val; > - } > + s->divider = deposit32(s->divider, 8 * addr, 8, val); > serial_update_parameters(s); > } else { > s->thr = (uint8_t) val; > @@ -364,7 +361,7 @@ static void serial_ioport_write(void *opaque, hwaddr addr, uint64_t val, > break; > case 1: > if (s->lcr & UART_LCR_DLAB) { > - s->divider = (s->divider & 0x00ff) | (val << 8); > + s->divider = deposit32(s->divider, 8 * addr, 8, val); > serial_update_parameters(s); > } else { > uint8_t changed = (s->ier ^ val) & 0x0f; > @@ -478,7 +475,7 @@ static uint64_t serial_ioport_read(void *opaque, hwaddr addr, unsigned size) > default: > case 0: > if (s->lcr & UART_LCR_DLAB) { > - ret = s->divider & 0xff; > + ret = extract16(s->divider, 8 * addr, 8); > } else { > if(s->fcr & UART_FCR_FE) { > ret = fifo8_is_empty(&s->recv_fifo) ? > @@ -502,7 +499,7 @@ static uint64_t serial_ioport_read(void *opaque, hwaddr addr, unsigned size) > break; > case 1: > if (s->lcr & UART_LCR_DLAB) { > - ret = (s->divider >> 8) & 0xff; > + ret = extract16(s->divider, 8 * addr, 8); > } else { > ret = s->ier; > } >
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