Remove "noreplacement" kernel command line option. (72538d85) · Commits · 戴 / test

It is no longer valid to not replace instructions, since we depend on different behaviour depending on CPU capabilities. If you need to limit the capabilities of the replacements (because the boot CPU has features that non-boot CPU's do not have, for example), you need to explicitly disable those capabilities that are not shared across all CPU's. For example, if your boot CPU has FXSR, but other CPU's in your system do not, you need to use the "nofxsr" kernel command line, not disable instruction replacement per se.

arch/i386/kernel/setup.c

+1 −13

Original line number	Diff line number	Diff line
		@@ -1414,7 +1414,7 @@ static struct nop {
		This runs before SMP is initialized to avoid SMP problems with
		self modifying code. This implies that assymetric systems where
		APs have less capabilities than the boot processor are not handled.
		In this case boot with "noreplacement". */
		Tough. Make sure you disable such features by hand. */
		void apply_alternatives(void start, void end)
		{
		struct alt_instr *a;
		@@ -1442,24 +1442,12 @@ void apply_alternatives(void start, void end)
		}
		}

		static int no_replacement __initdata = 0;

		void __init alternative_instructions(void)
		{
		extern struct alt_instr __alt_instructions[], __alt_instructions_end[];
		if (no_replacement)
		return;
		apply_alternatives(__alt_instructions, __alt_instructions_end);
		}

		static int __init noreplacement_setup(char *s)
		{
		no_replacement = 1;
		return 0;
		}

		__setup("noreplacement", noreplacement_setup);

		static char * __init machine_specific_memory_setup(void);

		#ifdef CONFIG_MCA

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