| Message ID | 1369320611-24956-1-git-send-email-julien.grall@linaro.org |
|---|---|
| State | Accepted, archived |
| Headers | show |
On Thu, 2013-05-23 at 15:50 +0100, Julien Grall wrote: > Introduce the function early_flush to wait until the UART has finished to > transfer the character. > When early printk is enabled, it's possible to loose the last characters if: > - the UART is initialized by the UART driver > - Xen hang > > This is result to a truncated message. To be sure that the message is fully > transfered by early_printk, add a call to early_flush. This will avoid lost > characters. > > Signed-off-by: Julien Grall <julien.grall@linaro.org> Acked + applied, thanks.
diff --git a/xen/arch/arm/arm32/debug.S b/xen/arch/arm/arm32/debug.S index 1bfbfc1..92f5724 100644 --- a/xen/arch/arm/arm32/debug.S +++ b/xen/arch/arm/arm32/debug.S @@ -32,6 +32,13 @@ early_putch: early_uart_transmit r1, r0 mov pc, lr +.globl early_flush +/* Flush the UART - this function is called by C */ +early_flush: + ldr r1, =FIXMAP_ADDR(FIXMAP_CONSOLE) /* r1 := VA UART base address */ + early_uart_ready r1, r2 + mov pc, lr + /* * Local variables: * mode: ASM diff --git a/xen/arch/arm/arm64/debug.S b/xen/arch/arm/arm64/debug.S index 38b7c74..c7b5e6c 100644 --- a/xen/arch/arm/arm64/debug.S +++ b/xen/arch/arm/arm64/debug.S @@ -32,6 +32,13 @@ early_putch: early_uart_transmit x15, w0 ret +.globl early_flush +/* Flush the UART - this function is called by C */ +early_flush: + ldr x15, =FIXMAP_ADDR(FIXMAP_CONSOLE) /* x15 := VA UART base address */ + early_uart_ready x15, 1 + ret + /* * Local variables: * mode: ASM diff --git a/xen/arch/arm/early_printk.c b/xen/arch/arm/early_printk.c index 5950323..ca151a5 100644 --- a/xen/arch/arm/early_printk.c +++ b/xen/arch/arm/early_printk.c @@ -16,6 +16,7 @@ #include <asm/early_printk.h> void early_putch(char c); +void early_flush(void); /* Early printk buffer */ static char __initdata buf[512]; @@ -34,6 +35,12 @@ static void __init early_vprintk(const char *fmt, va_list args) { vsnprintf(buf, sizeof(buf), fmt, args); early_puts(buf); + + /* + * Wait the UART has finished to transfer all characters before + * to continue. This will avoid lost characters if Xen abort. + */ + early_flush(); } void __init early_printk(const char *fmt, ...)
Introduce the function early_flush to wait until the UART has finished to transfer the character. When early printk is enabled, it's possible to loose the last characters if: - the UART is initialized by the UART driver - Xen hang This is result to a truncated message. To be sure that the message is fully transfered by early_printk, add a call to early_flush. This will avoid lost characters. Signed-off-by: Julien Grall <julien.grall@linaro.org> --- xen/arch/arm/arm32/debug.S | 7 +++++++ xen/arch/arm/arm64/debug.S | 7 +++++++ xen/arch/arm/early_printk.c | 7 +++++++ 3 files changed, 21 insertions(+)