Re: Dom0 kernel for Xen4.6 on R-Car H2 (LAGER)

[Julien Grall <julien.grall@citrix.com>]

On 21/10/15 17:05, Ferger, Max wrote:
> Hi!

Hello,

> Thanks for both DT fixes, the "add ranges;", and the "complete memory map".
> 
> Here are some findings:
> 
> * Linus' most recent version of the kernel [1] (configured with a mix of Xen/OMAP description [2] and lager_defconfig [3]) needs the 'add "ranges;"'-fixes, but does not access the otherwise unmapped address regions.
> * Renesas' Yocto/Poky 
> 
> Unfortunately, neither gives any message on the console, so I don't know their status.
> 
> [1] git clone git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
> [2] http://wiki.xenproject.org/wiki/Xen_ARM_with_Virtualization_Extensions/OMAP5432_uEVM
> [3] git clone https://github.com/renesas-devel/lager-config
> 
> As I see it, Xen issues no further warnings, but still Dom0 remains silent.

The console parameter in "xen,dom0-bootargs" seems to be wrong.
It should be console=hvc0

If it still doesn't work, you can apply the patch [1] to Linux
(it's based on the latest version). It will print everything on Xen
console even if the HVC console is not ready.

> I'm somewhat at a loss.  :-(
> 
> Greetings from Germany!

Regards,


[1]
diff --git a/drivers/tty/hvc/hvc_xen.c b/drivers/tty/hvc/hvc_xen.c
index fa816b7..b57ace0 100644
--- a/drivers/tty/hvc/hvc_xen.c
+++ b/drivers/tty/hvc/hvc_xen.c
@@ -638,7 +638,7 @@ 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 8f0324e..29a19af 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -1652,6 +1652,8 @@ static size_t cont_print_text(char *text, size_t size)
        return textlen;
 }
 
+#include <xen/hvc-console.h>
+
 asmlinkage int vprintk_emit(int facility, int level,
                            const char *dict, size_t dictlen,
                            const char *fmt, va_list args)
@@ -1719,6 +1721,7 @@ asmlinkage int vprintk_emit(int facility, int level,
         * prefix which might be passed-in as a parameter.
         */
        text_len = vscnprintf(text, sizeof(textbuf), fmt, args);
+       xen_raw_console_write(text);
 
        /* mark and strip a trailing newline */
        if (text_len && text[text_len-1] == '\n') {




-- 
Julien Grall