Commit a762f4ff authored by Marc Zyngier's avatar Marc Zyngier Committed by Will Deacon
Browse files

arm64: Move "nokaslr" over to the early cpufeature infrastructure 



Given that the early cpufeature infrastructure has borrowed quite
a lot of code from the kaslr implementation, let's reimplement
the matching of the "nokaslr" option with it.

Signed-off-by: default avatarMarc Zyngier <maz@kernel.org>
Acked-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
Acked-by: default avatarDavid Brazdil <dbrazdil@google.com>
Link: https://lore.kernel.org/r/20210208095732.3267263-20-maz@kernel.org


Signed-off-by: default avatarWill Deacon <will@kernel.org>
parent 166cc2a4

arch/arm64/kernel/idreg-override.c

+15 −0
Original line number Diff line number Diff line
@@ -37,8 +37,22 @@ static const struct ftr_set_desc mmfr1 __initconst = { 
	},

};



extern struct arm64_ftr_override kaslr_feature_override;



static const struct ftr_set_desc kaslr __initconst = {

	.name		= "kaslr",

#ifdef CONFIG_RANDOMIZE_BASE

	.override	= &kaslr_feature_override,

#endif

	.fields		= {

		{ "disabled", 0 },

		{}

	},

};



static const struct ftr_set_desc * const regs[] __initconst = {

	&mmfr1,

	&kaslr,

};



static const struct {
@@ -47,6 +61,7 @@ static const struct { 
} aliases[] __initconst = {

	{ "kvm-arm.mode=nvhe",		"id_aa64mmfr1.vh=0" },

	{ "kvm-arm.mode=protected",	"id_aa64mmfr1.vh=0" },

	{ "nokaslr",			"kaslr.disabled=1" },

};



static int __init find_field(const char *cmdline,

arch/arm64/kernel/kaslr.c

+2 −34
Original line number Diff line number Diff line
@@ -51,39 +51,7 @@ static __init u64 get_kaslr_seed(void *fdt) 
	return ret;

}



static __init bool cmdline_contains_nokaslr(const u8 *cmdline)

{

	const u8 *str;



	str = strstr(cmdline, "nokaslr");

	return str == cmdline || (str > cmdline && *(str - 1) == ' ');

}



static __init bool is_kaslr_disabled_cmdline(void *fdt)

{

	if (!IS_ENABLED(CONFIG_CMDLINE_FORCE)) {

		int node;

		const u8 *prop;



		node = fdt_path_offset(fdt, "/chosen");

		if (node < 0)

			goto out;



		prop = fdt_getprop(fdt, node, "bootargs", NULL);

		if (!prop)

			goto out;



		if (cmdline_contains_nokaslr(prop))

			return true;



		if (IS_ENABLED(CONFIG_CMDLINE_EXTEND))

			goto out;



		return false;

	}

out:

	return cmdline_contains_nokaslr(CONFIG_CMDLINE);

}

struct arm64_ftr_override kaslr_feature_override __initdata;



/*

 * This routine will be executed with the kernel mapped at its default virtual
@@ -126,7 +94,7 @@ u64 __init kaslr_early_init(void) 
	 * Check if 'nokaslr' appears on the command line, and

	 * return 0 if that is the case.

	 */

	if (is_kaslr_disabled_cmdline(fdt)) {

	if (kaslr_feature_override.val & kaslr_feature_override.mask & 0xf) {

		kaslr_status = KASLR_DISABLED_CMDLINE;

		return 0;

	}