x86 setup: early cmdline parser handle boolean options
This patch extends the early commandline parser to support boolean options.
The current version in mainline only supports parsing "option=arg" value pairs.
With this it should be easy making other messages like "Uncompressing kernel"
honour the "quiet" parameter, too.
Signed-off-by: Roland Kletzing <devzero@web.de>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/arch/x86/boot/cmdline.c b/arch/x86/boot/cmdline.c
index 34bb778..cc65a33 100644
--- a/arch/x86/boot/cmdline.c
+++ b/arch/x86/boot/cmdline.c
@@ -95,3 +95,68 @@
return len;
}
+
+/*
+ * Find a boolean option (like quiet,noapic,nosmp....)
+ *
+ * Returns the position of that option (starts counting with 1)
+ * or 0 on not found
+ */
+int cmdline_find_option_bool(const char *option)
+{
+ u32 cmdline_ptr = boot_params.hdr.cmd_line_ptr;
+ addr_t cptr;
+ char c;
+ int pos =0 , wstart = 0;
+ const char *opptr = NULL;
+ enum {
+ st_wordstart, /* Start of word/after whitespace */
+ st_wordcmp, /* Comparing this word */
+ st_wordskip, /* Miscompare, skip */
+ } state = st_wordstart;
+
+ if (!cmdline_ptr || cmdline_ptr >= 0x100000)
+ return -1; /* No command line, or inaccessible */
+
+ cptr = cmdline_ptr & 0xf;
+ set_fs(cmdline_ptr >> 4);
+
+ while (cptr < 0x10000) {
+ c = rdfs8(cptr++);
+ pos++;
+
+ switch (state) {
+ case st_wordstart:
+ if (!c)
+ return 0;
+ else if (myisspace(c))
+ break;
+
+ state = st_wordcmp;
+ opptr = option;
+ wstart = pos;
+ /* fall through */
+
+ case st_wordcmp:
+ if (!*opptr)
+ if (!c || myisspace(c))
+ return wstart;
+ else
+ state = st_wordskip;
+ else if (!c)
+ return 0;
+ else if (c != *opptr++)
+ state = st_wordskip;
+ break;
+
+ case st_wordskip:
+ if (!c)
+ return 0;
+ else if (myisspace(c))
+ state = st_wordstart;
+ break;
+ }
+ }
+
+ return 0; /* Buffer overrun */
+}