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authorNicholas Piggin <npiggin@gmail.com>2022-09-16 14:07:49 +1000
committerMichael Ellerman <mpe@ellerman.id.au>2022-09-26 20:58:16 +1000
commit7082f8e7d2276575a8806370007cbb4a7b9abdce (patch)
tree8b534ee44f283a58de7353121e364a7f9e524747 /arch/powerpc/mm
parentb150a4d12b919baf956b807aa305cf78df03d0fe (diff)
downloadlinux-7082f8e7d2276575a8806370007cbb4a7b9abdce.tar.gz
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

Diffstat (limited to 'arch/powerpc/mm')
-rw-r--r--arch/powerpc/mm/book3s32/mmu.c2
-rw-r--r--arch/powerpc/mm/book3s64/hash_pgtable.c2
-rw-r--r--arch/powerpc/mm/book3s64/radix_pgtable.c2
-rw-r--r--arch/powerpc/mm/pgtable_32.c7
4 files changed, 7 insertions, 6 deletions
diff --git a/arch/powerpc/mm/book3s32/mmu.c b/arch/powerpc/mm/book3s32/mmu.c
index 250d174459d4..e5ee05c234c7 100644
--- a/arch/powerpc/mm/book3s32/mmu.c
+++ b/arch/powerpc/mm/book3s32/mmu.c
@@ -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;
 	}
 
diff --git a/arch/powerpc/mm/book3s64/hash_pgtable.c b/arch/powerpc/mm/book3s64/hash_pgtable.c
index ae008b9df0e6..28332001bd87 100644
--- a/arch/powerpc/mm/book3s64/hash_pgtable.c
+++ b/arch/powerpc/mm/book3s64/hash_pgtable.c
@@ -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);
 
diff --git a/arch/powerpc/mm/book3s64/radix_pgtable.c b/arch/powerpc/mm/book3s64/radix_pgtable.c
index 9f880f91f584..60c277a9b043 100644
--- a/arch/powerpc/mm/book3s64/radix_pgtable.c
+++ b/arch/powerpc/mm/book3s64/radix_pgtable.c
@@ -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);
 }
diff --git a/arch/powerpc/mm/pgtable_32.c b/arch/powerpc/mm/pgtable_32.c
index 3ac73f9fb5d5..5c02fd08d61e 100644
--- a/arch/powerpc/mm/pgtable_32.c
+++ b/arch/powerpc/mm/pgtable_32.c
@@ -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);