Re: [PATCH v4 15/21] arm64: Add an aliasing facility for the idreg override

David Brazdil
2021-01-18T13:20:05Z

On Mon, Jan 18, 2021 at 09:45:27AM +0000, Marc Zyngier wrote:
> In order to map the override of idregs to options that a user
> can easily understand, let's introduce yet another option
> array, which maps an option to the corresponding idreg options.
>
> Signed-off-by: Marc Zyngier <maz@kernel.org>
Acked-by: David Brazdil <dbrazdil@google.com>

> ---
> arch/arm64/kernel/idreg-override.c | 20 ++++++++++++++++++++
> 1 file changed, 20 insertions(+)
>
> diff --git a/arch/arm64/kernel/idreg-override.c b/arch/arm64/kernel/idreg-override.c
> index 75d9845f489b..16bc8b3b93ae 100644
> --- a/arch/arm64/kernel/idreg-override.c
> +++ b/arch/arm64/kernel/idreg-override.c
> @@ -37,6 +37,12 @@ static const struct reg_desc * const regs[] __initdata = {
> &mmfr1,
> };
>
> +static const struct {
> + const char * const alias;
> + const char * const feature;
> +} aliases[] __initdata = {
> +};
> +
> static int __init find_field(const char *cmdline, const struct reg_desc *reg,
> int f, u64 *v)
> {
> @@ -80,6 +86,18 @@ static void __init match_options(const char *cmdline)
> }
> }
>
> +static __init void match_aliases(const char *cmdline)
> +{
> + int i;
> +
> + for (i = 0; i < ARRAY_SIZE(aliases); i++) {
> + char *str = strstr(cmdline, aliases[i].alias);
> +
> + if ((str == cmdline || (str > cmdline && *(str - 1) == ' ')))

nit: Extract to a 'cmdline_contains' helper? Took me a good few seconds to
parse this in the previous patch. Giving it a name would help, and now it's
also shared.

> + match_options(aliases[i].feature);
> + }
> +}
> +
> static __init void parse_cmdline(void)
> {
> if (!IS_ENABLED(CONFIG_CMDLINE_FORCE)) {
> @@ -100,6 +118,7 @@ static __init void parse_cmdline(void)
> goto out;
>
> match_options(prop);
> + match_aliases(prop);
>
> if (!IS_ENABLED(CONFIG_CMDLINE_EXTEND))
> return;
> @@ -107,6 +126,7 @@ static __init void parse_cmdline(void)
>
> out:
> match_options(CONFIG_CMDLINE);
> + match_aliases(CONFIG_CMDLINE);
> }
>
> void __init init_shadow_regs(void)
> --
> 2.29.2