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Commit 0c2a3913 authored by Andi Kleen's avatar Andi Kleen Committed by Ingo Molnar
Browse files

x86/fpu: Parse clearcpuid= as early XSAVE argument 



With a followon patch we want to make clearcpuid affect the XSAVE
configuration. But xsave is currently initialized before arguments
are parsed. Move the clearcpuid= parsing into the special
early xsave argument parsing code.

Since clearcpuid= contains a = we need to keep the old __setup
around as a dummy, otherwise it would end up as a environment
variable in init's environment.

Signed-off-by: default avatarAndi Kleen <ak@linux.intel.com>
Reviewed-by: default avatarThomas Gleixner <tglx@linutronix.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20171013215645.23166-4-andi@firstfloor.org


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 0b00de85

arch/x86/kernel/cpu/common.c

+7 −9
Original line number Diff line number Diff line
@@ -1301,18 +1301,16 @@ void print_cpu_info(struct cpuinfo_x86 *c) 
		pr_cont(")\n");

}



static __init int setup_disablecpuid(char *arg)

/*

 * clearcpuid= was already parsed in fpu__init_parse_early_param.

 * But we need to keep a dummy __setup around otherwise it would

 * show up as an environment variable for init.

 */

static __init int setup_clearcpuid(char *arg)

{

	int bit;



	if (get_option(&arg, &bit) && bit >= 0 && bit < NCAPINTS * 32)

		setup_clear_cpu_cap(bit);

	else

		return 0;



	return 1;

}

__setup("clearcpuid=", setup_disablecpuid);

__setup("clearcpuid=", setup_clearcpuid);



#ifdef CONFIG_X86_64

DEFINE_PER_CPU_FIRST(union irq_stack_union,

arch/x86/kernel/fpu/init.c

+11 −0
Original line number Diff line number Diff line
@@ -249,6 +249,10 @@ static void __init fpu__init_system_ctx_switch(void) 
 */

static void __init fpu__init_parse_early_param(void)

{

	char arg[32];

	char *argptr = arg;

	int bit;



	if (cmdline_find_option_bool(boot_command_line, "no387"))

		setup_clear_cpu_cap(X86_FEATURE_FPU);
@@ -266,6 +270,13 @@ static void __init fpu__init_parse_early_param(void) 


	if (cmdline_find_option_bool(boot_command_line, "noxsaves"))

		setup_clear_cpu_cap(X86_FEATURE_XSAVES);



	if (cmdline_find_option(boot_command_line, "clearcpuid", arg,

				sizeof(arg)) &&

	    get_option(&argptr, &bit) &&

	    bit >= 0 &&

	    bit < NCAPINTS * 32)

		setup_clear_cpu_cap(bit);

}



/*