Commit 7082f8e7 authored by Nicholas Piggin's avatar Nicholas Piggin Committed by Michael Ellerman
Browse files

powerpc: move __end_rodata to cover arch read-only sections 



powerpc has a number of read-only sections and tables that are put after
RO_DATA(). Move the __end_rodata symbol to cover these as well.

Setting memory to read-only at boot is done using __init_begin, change
that to use __end_rodata.

This makes is_kernel_rodata() exactly cover the read-only region, as
well as other things using __end_rodata (e.g., kernel/dma/debug.c).
Boot dmesg also prints the rodata size more accurately.

Signed-off-by: default avatarNicholas Piggin <npiggin@gmail.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220916040755.2398112-2-npiggin@gmail.com
parent b150a4d1

arch/powerpc/kernel/vmlinux.lds.S

+1 −0
Original line number Diff line number Diff line
@@ -219,6 +219,7 @@ SECTIONS 
	 */

	. = ALIGN(STRICT_ALIGN_SIZE);

	__srwx_boundary = .;

	__end_rodata = .;

	__init_begin = .;



/*

arch/powerpc/mm/book3s32/mmu.c

+1 −1
Original line number Diff line number Diff line
@@ -240,7 +240,7 @@ void mmu_mark_rodata_ro(void) 
	for (i = 0; i < nb; i++) {

		struct ppc_bat *bat = BATS[i];



		if (bat_addrs[i].start < (unsigned long)__init_begin)

		if (bat_addrs[i].start < (unsigned long)__end_rodata)

			bat[1].batl = (bat[1].batl & ~BPP_RW) | BPP_RX;

	}

arch/powerpc/mm/book3s64/hash_pgtable.c

+1 −1
Original line number Diff line number Diff line
@@ -541,7 +541,7 @@ void hash__mark_rodata_ro(void) 
	unsigned long start, end, pp;



	start = (unsigned long)_stext;

	end = (unsigned long)__init_begin;

	end = (unsigned long)__end_rodata;



	pp = htab_convert_pte_flags(pgprot_val(PAGE_KERNEL_ROX), HPTE_USE_KERNEL_KEY);

arch/powerpc/mm/book3s64/radix_pgtable.c

+1 −1
Original line number Diff line number Diff line
@@ -228,7 +228,7 @@ void radix__mark_rodata_ro(void) 
	unsigned long start, end;



	start = (unsigned long)_stext;

	end = (unsigned long)__init_begin;

	end = (unsigned long)__end_rodata;



	radix__change_memory_range(start, end, _PAGE_WRITE);

}

arch/powerpc/mm/pgtable_32.c

+4 −3
Original line number Diff line number Diff line
@@ -158,10 +158,11 @@ void mark_rodata_ro(void) 
	}



	/*

	 * mark .text and .rodata as read only. Use __init_begin rather than

	 * __end_rodata to cover NOTES and EXCEPTION_TABLE.

	 * mark text and rodata as read only. __end_rodata is set by

	 * powerpc's linker script and includes tables and data

	 * requiring relocation which are not put in RO_DATA.

	 */

	numpages = PFN_UP((unsigned long)__init_begin) -

	numpages = PFN_UP((unsigned long)__end_rodata) -

		   PFN_DOWN((unsigned long)_stext);



	set_memory_ro((unsigned long)_stext, numpages);