Commit a86aa72e authored by Ard Biesheuvel's avatar Ard Biesheuvel Committed by Catalin Marinas
Browse files

arm64: kernel: Don't rely on objcopy to make code under pi/ __init 



We will add some code under pi/ that contains global variables that
should not end up in __initdata, as they will not be writable via the
initial ID map. So only rely on objcopy for making the libfdt code
__init, and use explicit annotations for the rest.

Signed-off-by: default avatarArd Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20240214122845.2033971-47-ardb+git@google.com


Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
parent 48157aa3

arch/arm64/kernel/pi/Makefile

+4 −2
Original line number Diff line number Diff line
@@ -28,11 +28,13 @@ quiet_cmd_piobjcopy = $(quiet_cmd_objcopy) 
      cmd_piobjcopy = $(cmd_objcopy) && $(obj)/relacheck $(@) $(<)



$(obj)/%.pi.o: OBJCOPYFLAGS := --prefix-symbols=__pi_ \

			       --remove-section=.note.gnu.property \

			       --prefix-alloc-sections=.init

			       --remove-section=.note.gnu.property

$(obj)/%.pi.o: $(obj)/%.o $(obj)/relacheck FORCE

	$(call if_changed,piobjcopy)



# ensure that all the lib- code ends up as __init code and data

$(obj)/lib-%.pi.o: OBJCOPYFLAGS += --prefix-alloc-sections=.init



$(obj)/lib-%.o: $(srctree)/lib/%.c FORCE

	$(call if_changed_rule,cc_o_c)

arch/arm64/kernel/pi/kaslr_early.c

+9 −7
Original line number Diff line number Diff line
@@ -17,7 +17,7 @@ 
#include <asm/pgtable.h>



/* taken from lib/string.c */

static char *__strstr(const char *s1, const char *s2)

static char *__init __strstr(const char *s1, const char *s2)

{

	size_t l1, l2;
@@ -33,7 +33,7 @@ static char *__strstr(const char *s1, const char *s2) 
	}

	return NULL;

}

static bool cmdline_contains_nokaslr(const u8 *cmdline)

static bool __init cmdline_contains_nokaslr(const u8 *cmdline)

{

	const u8 *str;
@@ -41,7 +41,7 @@ static bool cmdline_contains_nokaslr(const u8 *cmdline) 
	return str == cmdline || (str > cmdline && *(str - 1) == ' ');

}



static bool is_kaslr_disabled_cmdline(void *fdt)

static bool __init is_kaslr_disabled_cmdline(void *fdt)

{

	if (!IS_ENABLED(CONFIG_CMDLINE_FORCE)) {

		int node;
@@ -67,17 +67,19 @@ static bool is_kaslr_disabled_cmdline(void *fdt) 
	return cmdline_contains_nokaslr(CONFIG_CMDLINE);

}



static u64 get_kaslr_seed(void *fdt)

static u64 __init get_kaslr_seed(void *fdt)

{

	static char const chosen_str[] __initconst = "chosen";

	static char const seed_str[] __initconst = "kaslr-seed";

	int node, len;

	fdt64_t *prop;

	u64 ret;



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

	node = fdt_path_offset(fdt, chosen_str);

	if (node < 0)

		return 0;



	prop = fdt_getprop_w(fdt, node, "kaslr-seed", &len);

	prop = fdt_getprop_w(fdt, node, seed_str, &len);

	if (!prop || len != sizeof(u64))

		return 0;
@@ -86,7 +88,7 @@ static u64 get_kaslr_seed(void *fdt) 
	return ret;

}



asmlinkage u64 kaslr_early_init(void *fdt)

asmlinkage u64 __init kaslr_early_init(void *fdt)

{

	u64 seed, range;