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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: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220916040755.2398112-2-npiggin@gmail.com
This commit is contained in:
Nicholas Piggin 2022-09-16 14:07:49 +10:00 committed by Michael Ellerman
parent b150a4d12b
commit 7082f8e7d2
5 changed files with 8 additions and 6 deletions
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1
arch/powerpc/kernel/vmlinux.lds.S
View File

@ -219,6 +219,7 @@ SECTIONS
*/
. = ALIGN(STRICT_ALIGN_SIZE);
__srwx_boundary = .;
__end_rodata = .;
__init_begin = .;
/*

2
arch/powerpc/mm/book3s32/mmu.c
View File

@ -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;
}

2
arch/powerpc/mm/book3s64/hash_pgtable.c
View File

@ -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);

2
arch/powerpc/mm/book3s64/radix_pgtable.c
View File

@ -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);
}

7
arch/powerpc/mm/pgtable_32.c
View File

@ -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);