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bsp/arm/tms570: protect against baud divide by zero

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tms570_sci_set_attributes has no protection against 0 baud rate
rtems_termios_baud_to_number documentation shows it can return 0
Can result in divide by zero inside tms570_sci_set_attributes in
at least one or two locations (and then also
tms570_sci_interrupt_last_close).
Also adds defensive final break in switch in parity bit switch.
This commit is contained in:
Avi Weiss
2026-04-24 16:03:07 +02:00
parent 7e4ab139d0
commit 1d90aa13b7
1 changed files with 17 additions and 7 deletions
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bsps/arm/tms570/console/tms570-sci.c
+17 -7
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@@ -255,8 +255,15 @@ bool tms570_sci_set_attributes(
rtems_termios_device_lock_acquire( base, &lock_context );
while ( (ctx->regs->GCR1 & TMS570_SCI_GCR1_TXENA) &&
(ctx->regs->FLR & flr_tx_ready) != flr_tx_ready) {
if ( baudrate == 0 ) {
rtems_termios_device_lock_release( base, &lock_context );
return false;
}
while (
( ctx->regs->GCR1 & TMS570_SCI_GCR1_TXENA ) &&
( ctx->regs->FLR & flr_tx_ready ) != flr_tx_ready
) {
/*
* There are pending characters in the hardware,
* change in the middle of the character Tx leads
@@ -298,6 +305,7 @@ bool tms570_sci_set_attributes(
case PARODD:
/* No Parity */
ctx->regs->GCR1 &= ~TMS570_SCI_GCR1_PARITY_ENA;
break;
}
/* Apply baudrate to the hardware */
@@ -594,11 +602,13 @@ static void tms570_sci_interrupt_last_close(
tms570_sci_disable_interrupts( ctx );
rtems_termios_device_lock_release( base, &lock_context );
tw = rtems_clock_get_ticks_per_second();
baudrate = rtems_termios_baud_to_number(cfgetospeed(&tty->termios));
tw = tw * 10 / baudrate + 1;
while ( ( ctx->regs->FLR & TMS570_SCI_FLR_TX_EMPTY ) == 0 ) {
rtems_task_wake_after(tw);
baudrate = rtems_termios_baud_to_number( cfgetospeed( &tty->termios ) );
if ( baudrate > 0 ) {
tw = rtems_clock_get_ticks_per_second();
tw = tw * 10 / baudrate + 1;
while ( ( ctx->regs->FLR & TMS570_SCI_FLR_TX_EMPTY ) == 0 ) {
rtems_task_wake_after( tw );
}
}
/* uninstall ISR */