[PATCH] arm64: fix rodata=full again

[Ard Biesheuvel]

Commit 2e8cff0a0eee87b2 ("arm64: fix rodata=full") addressed a couple of
issues with the rodata= kernel command line option, which is not a
simple boolean on arm64, and inadvertently got broken due to changes in
the generic bool handling.

Unfortunately, the resulting code never clears the rodata_full boolean
variable if it defaults to true and rodata=on or rodata=off is passed,
as the generic code is not aware of the existence of this variable.

Given the way this code is plumbed together, clearing rodata_full when
returning false from arch_parse_debug_rodata() may result in
inconsistencies if the generic code decides that it cannot parse the
right hand side, so the best way to deal with this is to only take
rodata_full in account if rodata_enabled is also true.

Fixes: 2e8cff0a0eee87b2 ("arm64: fix rodata=full")
Signed-off-by: Ard Biesheuvel <ardb at kernel.org>
---
 arch/arm64/mm/pageattr.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/mm/pageattr.c b/arch/arm64/mm/pageattr.c
index d107c3d434e22455..5922178d7a064c1c 100644
--- a/arch/arm64/mm/pageattr.c
+++ b/arch/arm64/mm/pageattr.c
@@ -26,7 +26,7 @@ bool can_set_direct_map(void)
 	 * mapped at page granularity, so that it is possible to
 	 * protect/unprotect single pages.
 	 */
-	return rodata_full || debug_pagealloc_enabled() ||
+	return (rodata_enabled && rodata_full) || debug_pagealloc_enabled() ||
 		IS_ENABLED(CONFIG_KFENCE);
 }
 
@@ -102,7 +102,8 @@ static int change_memory_common(unsigned long addr, int numpages,
 	 * If we are manipulating read-only permissions, apply the same
 	 * change to the linear mapping of the pages that back this VM area.
 	 */
-	if (rodata_full && (pgprot_val(set_mask) == PTE_RDONLY ||
+	if (rodata_enabled &&
+	    rodata_full && (pgprot_val(set_mask) == PTE_RDONLY ||
 			    pgprot_val(clear_mask) == PTE_RDONLY)) {
 		for (i = 0; i < area->nr_pages; i++) {
 			__change_memory_common((u64)page_address(area->pages[i]),
-- 
2.35.1