[PATCH] x86_64: Check that early arguments are words on their own

We've always had the problem that arguments only did a prefix match,
which resulted e.g.  in noapic and noapictimer getting confused.

Fix the early argument parsing code to always check that arguments are
whole words (except for those that take additional arguments of course)
I factored out the checking code for that while also makes the code
easier to maintain.

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

arch/x86_64/kernel/setup.c

@@ -46,6 +46,7 @@
 #include <linux/cpufreq.h>
 #include <linux/dmi.h>
 #include <linux/dma-mapping.h>
+#include <linux/ctype.h>
 
 #include <asm/mtrr.h>
 #include <asm/uaccess.h>
@@ -270,6 +271,13 @@ static void __init probe_roms(void)
 	}
 }
 
+/* Check for full argument with no trailing characters */
+static int fullarg(char *p, char *arg)
+{
+	int l = strlen(arg);
+	return !memcmp(p, arg, l) && (p[l] == 0 || isspace(p[l]));
+}
+
 static __init void parse_cmdline_early (char ** cmdline_p)
 {
 	char c = ' ', *to = command_line, *from = COMMAND_LINE;
@@ -293,63 +301,58 @@ static __init void parse_cmdline_early (char ** cmdline_p)
 #endif
 #ifdef CONFIG_ACPI
 		/* "acpi=off" disables both ACPI table parsing and interpreter init */
-		if (!memcmp(from, "acpi=off", 8))
+		if (fullarg(from,"acpi=off"))
 			disable_acpi();
 
-		if (!memcmp(from, "acpi=force", 10)) { 
+		if (fullarg(from, "acpi=force")) { 
 			/* add later when we do DMI horrors: */
 			acpi_force = 1;
 			acpi_disabled = 0;
 		}
 
 		/* acpi=ht just means: do ACPI MADT parsing 
 		   at bootup, but don't enable the full ACPI interpreter */
-		if (!memcmp(from, "acpi=ht", 7)) { 
+		if (fullarg(from, "acpi=ht")) { 
 			if (!acpi_force)
 				disable_acpi();
 			acpi_ht = 1; 
 		}
-                else if (!memcmp(from, "pci=noacpi", 10)) 
+                else if (fullarg(from, "pci=noacpi")) 
 			acpi_disable_pci();
-		else if (!memcmp(from, "acpi=noirq", 10))
+		else if (fullarg(from, "acpi=noirq"))
 			acpi_noirq_set();
 
-		else if (!memcmp(from, "acpi_sci=edge", 13))
+		else if (fullarg(from, "acpi_sci=edge"))
 			acpi_sci_flags.trigger =  1;
-		else if (!memcmp(from, "acpi_sci=level", 14))
+		else if (fullarg(from, "acpi_sci=level"))
 			acpi_sci_flags.trigger = 3;
-		else if (!memcmp(from, "acpi_sci=high", 13))
+		else if (fullarg(from, "acpi_sci=high"))
 			acpi_sci_flags.polarity = 1;
-		else if (!memcmp(from, "acpi_sci=low", 12))
+		else if (fullarg(from, "acpi_sci=low"))
 			acpi_sci_flags.polarity = 3;
 
 		/* acpi=strict disables out-of-spec workarounds */
-		else if (!memcmp(from, "acpi=strict", 11)) {
+		else if (fullarg(from, "acpi=strict")) {
 			acpi_strict = 1;
 		}
 #ifdef CONFIG_X86_IO_APIC
-		else if (!memcmp(from, "acpi_skip_timer_override", 24))
+		else if (fullarg(from, "acpi_skip_timer_override"))
 			acpi_skip_timer_override = 1;
 #endif
 #endif
 
-		if (!memcmp(from, "disable_timer_pin_1", 19))
+		if (fullarg(from, "disable_timer_pin_1"))
 			disable_timer_pin_1 = 1;
-		if (!memcmp(from, "enable_timer_pin_1", 18))
+		if (fullarg(from, "enable_timer_pin_1"))
 			disable_timer_pin_1 = -1;
 
-		if (!memcmp(from, "nolapic", 7) ||
-		    !memcmp(from, "disableapic", 11))
+		if (fullarg(from, "nolapic") || fullarg(from, "disableapic"))
 			disable_apic = 1;
 
-		/* Don't confuse with noapictimer */
-		if (!memcmp(from, "noapic", 6) &&
-			(from[6] == ' ' || from[6] == 0))
+		if (fullarg(from, "noapic"))
 			skip_ioapic_setup = 1;
 
-		/* Make sure to not confuse with apic= */
-		if (!memcmp(from, "apic", 4) &&
-			(from[4] == ' ' || from[4] == 0)) {
+		if (fullarg(from,"apic")) {
 			skip_ioapic_setup = 0;
 			ioapic_force = 1;
 		}
@@ -388,7 +391,7 @@ static __init void parse_cmdline_early (char ** cmdline_p)
 			iommu_setup(from+6); 
 		}
 
-		if (!memcmp(from,"oops=panic", 10))
+		if (fullarg(from,"oops=panic"))
 			panic_on_oops = 1;
 
 		if (!memcmp(from, "noexec=", 7))