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authordevzero@web.de <devzero@web.de>2008-01-30 13:33:02 +0100
committerIngo Molnar <mingo@elte.hu>2008-01-30 13:33:02 +0100
commit32d0b9898029b7b3c7f161d31f57c4831d9049eb (patch)
tree3423478d043a18042590d494876ae7d0223bcea5 /arch/x86/boot/cmdline.c
parent811a0fff5d6e80e18e06be88e0fb685f3924bf8f (diff)
downloadlinux-32d0b9898029b7b3c7f161d31f57c4831d9049eb.tar.bz2
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>
Diffstat (limited to 'arch/x86/boot/cmdline.c')
-rw-r--r--arch/x86/boot/cmdline.c65
1 files changed, 65 insertions, 0 deletions
diff --git a/arch/x86/boot/cmdline.c b/arch/x86/boot/cmdline.c
index 34bb778c4357..cc65a33bf65c 100644
--- a/arch/x86/boot/cmdline.c
+++ b/arch/x86/boot/cmdline.c
@@ -95,3 +95,68 @@ int cmdline_find_option(const char *option, char *buffer, int bufsize)
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 */
+}