diff options
Diffstat (limited to 'arch/x86_64')
| -rw-r--r-- | arch/x86_64/kernel/early_printk.c | 46 |
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); |