Commit 213aa670 authored by Helge Deller's avatar Helge Deller
Browse files

parisc: Delay write-protection until mark_rodata_ro() call 



Do not write-protect the kernel read-only and __ro_after_init sections
earlier than before mark_rodata_ro() is called.  This fixes a boot issue on
parisc which is triggered by commit 91a1d97e ("jump_label,module: Don't
alloc static_key_mod for __ro_after_init keys"). That commit may modify
static key contents in the __ro_after_init section at bootup, so this
section needs to be writable at least until mark_rodata_ro() is called.

Signed-off-by: default avatarHelge Deller <deller@gmx.de>
Reported-by: default avatarmatoro <matoro_mailinglist_kernel@matoro.tk>
Reported-by: default avatarChristoph Biedl <linux-kernel.bfrz@manchmal.in-ulm.de>
Tested-by: default avatarChristoph Biedl <linux-kernel.bfrz@manchmal.in-ulm.de>
Link: https://lore.kernel.org/linux-parisc/096cad5aada514255cd7b0b9dbafc768@matoro.tk/#r
Fixes: 91a1d97e ("jump_label,module: Don't alloc static_key_mod for __ro_after_init keys")
Cc: stable@vger.kernel.org # v6.10+
parent 5be63fc1

arch/parisc/mm/init.c

+11 −5
Original line number Diff line number Diff line
@@ -459,7 +459,6 @@ void free_initmem(void) 
	unsigned long kernel_end  = (unsigned long)&_end;



	/* Remap kernel text and data, but do not touch init section yet. */

	kernel_set_to_readonly = true;

	map_pages(init_end, __pa(init_end), kernel_end - init_end,

		  PAGE_KERNEL, 0);
@@ -493,11 +492,18 @@ void free_initmem(void) 
#ifdef CONFIG_STRICT_KERNEL_RWX

void mark_rodata_ro(void)

{

	/* rodata memory was already mapped with KERNEL_RO access rights by

           pagetable_init() and map_pages(). No need to do additional stuff here */

	unsigned long roai_size = __end_ro_after_init - __start_ro_after_init;

	unsigned long start = (unsigned long) &__start_rodata;

	unsigned long end = (unsigned long) &__end_rodata;



	pr_info("Write protecting the kernel read-only data: %luk\n",

	       (end - start) >> 10);



	kernel_set_to_readonly = true;

	map_pages(start, __pa(start), end - start, PAGE_KERNEL, 0);



	pr_info("Write protected read-only-after-init data: %luk\n", roai_size >> 10);

	/* force the kernel to see the new page table entries */

	flush_cache_all();

	flush_tlb_all();

}

#endif