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hv:use spinlock_irqsave_obtain api for uart

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replace spinlock_obtain/spinlock_release with spinlock_irqsave_obtain
and spinlock_irqrestore_release to avoid dead lock for uart module.

this uart lock may be accessed in ISR context like this path:
   dispatch_interrupt->pr_err/pr_xxx or printf
   ->console_write->uart16550_puts

Tracked-On: #4958

Signed-off-by: Mingqiang Chi <mingqiang.chi@intel.com>
This commit is contained in:
Mingqiang Chi 2020-07-01 14:53:25 +08:00 committed by wenlingz
parent 0080c6ca72
commit b1357cdc0d
1 changed files with 8 additions and 5 deletions
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13
hypervisor/debug/uart16550.c
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@ -172,20 +172,20 @@ void uart16550_init(bool early_boot)
char uart16550_getc(void) char uart16550_getc(void)
{ {
char ret = -1; char ret = -1;
uint64_t rflags;
if (!uart.enabled) { if (!uart.enabled) {
return ret; return ret;
} }
spinlock_obtain(&uart.rx_lock); spinlock_irqsave_obtain(&uart.rx_lock, &rflags);
/* If a character has been received, read it */ /* If a character has been received, read it */
if ((uart16550_read_reg(uart, UART16550_LSR) & LSR_DR) == LSR_DR) { if ((uart16550_read_reg(uart, UART16550_LSR) & LSR_DR) == LSR_DR) {
/* Read a character */ /* Read a character */
ret = uart16550_read_reg(uart, UART16550_RBR); ret = uart16550_read_reg(uart, UART16550_RBR);
} }
spinlock_release(&uart.rx_lock); spinlock_irqrestore_release(&uart.rx_lock, rflags);
return ret; return ret;
} }
@ -210,10 +210,13 @@ static void uart16550_putc(char c)
size_t uart16550_puts(const char *buf, uint32_t len) size_t uart16550_puts(const char *buf, uint32_t len)
{ {
uint32_t i; uint32_t i;
uint64_t rflags;
if (!uart.enabled) { if (!uart.enabled) {
return len; return len;
} }
spinlock_obtain(&uart.tx_lock);
spinlock_irqsave_obtain(&uart.tx_lock, &rflags);
for (i = 0U; i < len; i++) { for (i = 0U; i < len; i++) {
/* Transmit character */ /* Transmit character */
uart16550_putc(*buf); uart16550_putc(*buf);
@ -223,7 +226,7 @@ size_t uart16550_puts(const char *buf, uint32_t len)
} }
buf++; buf++;
} }
spinlock_release(&uart.tx_lock); spinlock_irqrestore_release(&uart.tx_lock, rflags);
return len; return len;
} }