Re: [PATCH v4 22/22] x86/fpu/xstate: Introduce boot-parameters to control state component support

On 2/21/21 12:10 PM, Bae, Chang Seok wrote:

On Feb 21, 2021, at 11:30, Randy Dunlap [off-list ref] wrote:

quoted

Can we tell people (in this Doc file) where to look up the values that can be
used in xstate.enable and xstate.disable?

Perhaps add something like this with the change below:
    “See comment before function fpu__init_parse_early_param() in
     arch/x86/kernel/fpu/init.c."

Hi,

I was thinking more along the lines of where can I find the value
0x60000 or BIT(22) or BIT(19), for example and see what they mean,
even though it will likely be some abbreviation.

/*
 * The kernel parameter "xstate.enable='mask'" and "xstate.disable='mask'" have a
 * mask value in a subset of XFEATURE_MASK_CONFIGURABLE.
 *
 * The longest parameter is 22 octal number characters with '0' prefix and an extra
 * '\0' for termination.
 */
#define MAX_XSTATE_MASK_CHARS   24

/**
 * fpu__init_parse_early_param() - parse the xstate kernel parameters
 *
 * Parse them early because fpu__init_system() is executed before
 * parse_early_param().
 */
static void __init fpu__init_parse_early_param(void)

thanks.
-- 
~Randy