aboutsummaryrefslogtreecommitdiff
path: root/arch/x86_64
diff options
context:
space:
mode:
Diffstat (limited to 'arch/x86_64')
-rw-r--r--arch/x86_64/kernel/early_printk.c46
1 files changed, 46 insertions, 0 deletions
diff --git a/arch/x86_64/kernel/early_printk.c b/arch/x86_64/kernel/early_printk.c
index 9631c747c5e..9cd968dd0f5 100644
--- a/arch/x86_64/kernel/early_printk.c
+++ b/arch/x86_64/kernel/early_printk.c
@@ -5,6 +5,7 @@
#include <linux/tty.h>
#include <asm/io.h>
#include <asm/processor.h>
+#include <asm/fcntl.h>
/* Simple VGA output */
@@ -158,6 +159,47 @@ static struct console early_serial_console = {
.index = -1,
};
+/* Console interface to a host file on AMD's SimNow! */
+
+static int simnow_fd;
+
+enum {
+ MAGIC1 = 0xBACCD00A,
+ MAGIC2 = 0xCA110000,
+ XOPEN = 5,
+ XWRITE = 4,
+};
+
+static noinline long simnow(long cmd, long a, long b, long c)
+{
+ long ret;
+ asm volatile("cpuid" :
+ "=a" (ret) :
+ "b" (a), "c" (b), "d" (c), "0" (MAGIC1), "D" (cmd + MAGIC2));
+ return ret;
+}
+
+void __init simnow_init(char *str)
+{
+ char *fn = "klog";
+ if (*str == '=')
+ fn = ++str;
+ /* error ignored */
+ simnow_fd = simnow(XOPEN, (unsigned long)fn, O_WRONLY|O_APPEND|O_CREAT, 0644);
+}
+
+static void simnow_write(struct console *con, const char *s, unsigned n)
+{
+ simnow(XWRITE, simnow_fd, (unsigned long)s, n);
+}
+
+static struct console simnow_console = {
+ .name = "simnow",
+ .write = simnow_write,
+ .flags = CON_PRINTBUFFER,
+ .index = -1,
+};
+
/* Direct interface for emergencies */
struct console *early_console = &early_vga_console;
static int early_console_initialized = 0;
@@ -205,6 +247,10 @@ int __init setup_early_printk(char *opt)
max_xpos = SCREEN_INFO.orig_video_cols;
max_ypos = SCREEN_INFO.orig_video_lines;
early_console = &early_vga_console;
+ } else if (!strncmp(buf, "simnow", 6)) {
+ simnow_init(buf + 6);
+ early_console = &simnow_console;
+ keep_early = 1;
}
early_console_initialized = 1;
register_console(early_console);