| Message ID | alpine.DEB.2.02.1408071340190.2293@kaball.uk.xensource.com |
|---|---|
| State | New |
| Headers | show |
Thanks, I manged to do something similar in the meantime. I am seeing a crash after I do /etc/init.d/xencommns start [<ffffffc00038fee4>] clear_bit+0x14/0x30 [<ffffffc0003d9ca4>] ack_dynirq+0x44/0x58 [<ffffffc0000e6a34>] handle_edge_irq+0x74/0x178 [<ffffffc0003dc0e8>] evtchn_fifo_handle_events+0x280/0x288 [<ffffffc0003d8f50>] __xen_evtchn_do_upcall+0x68/0xd0 [<ffffffc0003d8fc0>] xen_hvm_evtchn_do_upcall+0x8/0x18 [<ffffffc00009271c>] xen_arm_callback+0x4c/0x68 [<ffffffc0000e7560>] handle_percpu_devid_irq+0x88/0x120 [<ffffffc0000e38b4>] generic_handle_irq+0x24/0x40 [<ffffffc000084890>] handle_IRQ+0x40/0xa8 [<ffffffc000081348>] gic_handle_irq+0x50/0xa0 I found that consume_one_event calls handle_irq_for_port which gets IRQ=7 in case of a crash. What is the use of IRQ 7 ? IRQ1 is UART which i saw in cat /proc/interrupts -Regards Manish On 7 August 2014 18:14, Stefano Stabellini <stefano.stabellini@eu.citrix.com > wrote: > On Thu, 7 Aug 2014, manish jaggi wrote: > > Hi Stefano, > > > > I am debugging a kernel crash when I start xencommons. If I add prints > in kernel the prints are only visible in > > dmesg and not on dom0 console. This makes it difficult to view kernel > printks at the time of crash. > > > > I tried xen_raw_printks but the print only comes when you press a key, > so while a crash is happening you cannot > > press a key. > > > > Is there a way to enable printks on hvc0 > > OR > > is there a way to dump __logbuf of linux from xen shell. > > You can hack printk and/or early_printk so that everything will go via > the Xen console, see below. Of course this is very hacky, don't tell > anybody that I wrote this patch ;-) > > > diff --git a/arch/arm64/kernel/early_printk.c > b/arch/arm64/kernel/early_printk.c > index 2dc36d0..38bcf29 100644 > --- a/arch/arm64/kernel/early_printk.c > +++ b/arch/arm64/kernel/early_printk.c > @@ -31,16 +31,16 @@ > static void __iomem *early_base; > static void (*printch)(char ch); > > +void xen_raw_console_write(const char *str); > /* > * PL011 single character TX. > */ > static void pl011_printch(char ch) > { > - while (readl_relaxed(early_base + UART01x_FR) & UART01x_FR_TXFF) > - ; > - writeb_relaxed(ch, early_base + UART01x_DR); > - while (readl_relaxed(early_base + UART01x_FR) & UART01x_FR_BUSY) > - ; > + char buf[2]; > + buf[0] = ch; > + buf[1] = '\0'; > + xen_raw_console_write(buf); > } > > /* > diff --git a/drivers/tty/hvc/hvc_xen.c b/drivers/tty/hvc/hvc_xen.c > index 2dc2831..1f586b3 100644 > --- a/drivers/tty/hvc/hvc_xen.c > +++ b/drivers/tty/hvc/hvc_xen.c > @@ -630,7 +630,7 @@ void xen_raw_console_write(const char *str) > ssize_t len = strlen(str); > int rc = 0; > > - if (xen_domain()) { > + if (1||xen_domain()) { > rc = dom0_write_console(0, str, len); > #ifdef CONFIG_X86 > if (rc == -ENOSYS && xen_hvm_domain()) > diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c > index 7228258..e035871 100644 > --- a/kernel/printk/printk.c > +++ b/kernel/printk/printk.c > @@ -1674,24 +1674,18 @@ EXPORT_SYMBOL(printk_emit); > * > * See the vsnprintf() documentation for format string extensions over > C99. > */ > +void xen_raw_console_write(const char *str); > asmlinkage __visible int printk(const char *fmt, ...) > { > va_list args; > - int r; > + static char buf[512]; > > -#ifdef CONFIG_KGDB_KDB > - if (unlikely(kdb_trap_printk)) { > - va_start(args, fmt); > - r = vkdb_printf(fmt, args); > - va_end(args); > - return r; > - } > -#endif > va_start(args, fmt); > - r = vprintk_emit(0, -1, NULL, 0, fmt, args); > + vsnprintf(buf, sizeof(buf), fmt, args); > va_end(args); > > - return r; > + xen_raw_console_write(buf); > + return 1; > } > EXPORT_SYMBOL(printk); >
diff --git a/arch/arm64/kernel/early_printk.c b/arch/arm64/kernel/early_printk.c index 2dc36d0..38bcf29 100644 --- a/arch/arm64/kernel/early_printk.c +++ b/arch/arm64/kernel/early_printk.c @@ -31,16 +31,16 @@ static void __iomem *early_base; static void (*printch)(char ch); +void xen_raw_console_write(const char *str); /* * PL011 single character TX. */ static void pl011_printch(char ch) { - while (readl_relaxed(early_base + UART01x_FR) & UART01x_FR_TXFF) - ; - writeb_relaxed(ch, early_base + UART01x_DR); - while (readl_relaxed(early_base + UART01x_FR) & UART01x_FR_BUSY) - ; + char buf[2]; + buf[0] = ch; + buf[1] = '\0'; + xen_raw_console_write(buf); } /* diff --git a/drivers/tty/hvc/hvc_xen.c b/drivers/tty/hvc/hvc_xen.c index 2dc2831..1f586b3 100644 --- a/drivers/tty/hvc/hvc_xen.c +++ b/drivers/tty/hvc/hvc_xen.c @@ -630,7 +630,7 @@ void xen_raw_console_write(const char *str) ssize_t len = strlen(str); int rc = 0; - if (xen_domain()) { + if (1||xen_domain()) { rc = dom0_write_console(0, str, len); #ifdef CONFIG_X86 if (rc == -ENOSYS && xen_hvm_domain()) diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index 7228258..e035871 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -1674,24 +1674,18 @@ EXPORT_SYMBOL(printk_emit); * * See the vsnprintf() documentation for format string extensions over C99. */ +void xen_raw_console_write(const char *str); asmlinkage __visible int printk(const char *fmt, ...) { va_list args; - int r; + static char buf[512]; -#ifdef CONFIG_KGDB_KDB - if (unlikely(kdb_trap_printk)) { - va_start(args, fmt); - r = vkdb_printf(fmt, args); - va_end(args); - return r; - } -#endif va_start(args, fmt); - r = vprintk_emit(0, -1, NULL, 0, fmt, args); + vsnprintf(buf, sizeof(buf), fmt, args); va_end(args); - return r; + xen_raw_console_write(buf); + return 1; } EXPORT_SYMBOL(printk);