Commit a004393f authored by Ard Biesheuvel's avatar Ard Biesheuvel Committed by Will Deacon
Browse files

arm64: idreg-override: use early FDT mapping in ID map 



Instead of calling into the kernel to map the FDT into the kernel page
tables before even calling start_kernel(), let's switch to the initial,
temporary mapping of the device tree that has been added to the ID map.

Signed-off-by: default avatarArd Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20220624150651.1358849-16-ardb@kernel.org


Signed-off-by: default avatarWill Deacon <will@kernel.org>
parent f70b3a23

arch/arm64/kernel/head.S

+1 −0
Original line number Diff line number Diff line
@@ -472,6 +472,7 @@ SYM_FUNC_START_LOCAL(__primary_switched) 
#endif

	mov	x0, x21				// pass FDT address in x0

	bl	early_fdt_map			// Try mapping the FDT early

	mov	x0, x22				// pass FDT address in x0

	bl	init_feature_override		// Parse cpu feature overrides

#ifdef CONFIG_RANDOMIZE_BASE

	tst	x23, ~(MIN_KIMG_ALIGN - 1)	// already running randomized?

arch/arm64/kernel/idreg-override.c

+6 −11
Original line number Diff line number Diff line
@@ -201,16 +201,11 @@ static __init void __parse_cmdline(const char *cmdline, bool parse_aliases) 
	} while (1);

}



static __init const u8 *get_bootargs_cmdline(void)

static __init const u8 *get_bootargs_cmdline(const void *fdt)

{

	const u8 *prop;

	void *fdt;

	int node;



	fdt = get_early_fdt_ptr();

	if (!fdt)

		return NULL;



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

	if (node < 0)

		return NULL;
@@ -222,9 +217,9 @@ static __init const u8 *get_bootargs_cmdline(void) 
	return strlen(prop) ? prop : NULL;

}



static __init void parse_cmdline(void)

static __init void parse_cmdline(const void *fdt)

{

	const u8 *prop = get_bootargs_cmdline();

	const u8 *prop = get_bootargs_cmdline(fdt);



	if (IS_ENABLED(CONFIG_CMDLINE_FORCE) || !prop)

		__parse_cmdline(CONFIG_CMDLINE, true);
@@ -234,9 +229,9 @@ static __init void parse_cmdline(void) 
}



/* Keep checkers quiet */

void init_feature_override(void);

void init_feature_override(const void *fdt);



asmlinkage void __init init_feature_override(void)

asmlinkage void __init init_feature_override(const void *fdt)

{

	int i;
@@ -247,7 +242,7 @@ asmlinkage void __init init_feature_override(void) 
		}

	}



	parse_cmdline();

	parse_cmdline(fdt);



	for (i = 0; i < ARRAY_SIZE(regs); i++) {

		if (regs[i]->override)