[PATCH RFC 01/17] arm64: consolidate rox page protection logic

[Russell King (Oracle)]

Consolidate the arm64 decision making for the page protections used
for executable pages, used by both the trampoline code and the kernel
text mapping code.

Signed-off-by: Russell King (Oracle) <rmk+kernel at armlinux.org.uk>
---
 arch/arm64/mm/mmu.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index af6bc8403ee4..4829abe017e9 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -663,12 +663,17 @@ static void __init map_kernel_segment(pgd_t *pgdp, void *va_start, void *va_end,
 	vm_area_add_early(vma);
 }
 
+static pgprot_t kernel_exec_prot(void)
+{
+	return rodata_enabled ? PAGE_KERNEL_ROX : PAGE_KERNEL_EXEC;
+}
+
 #ifdef CONFIG_UNMAP_KERNEL_AT_EL0
 static int __init map_entry_trampoline(void)
 {
 	int i;
 
-	pgprot_t prot = rodata_enabled ? PAGE_KERNEL_ROX : PAGE_KERNEL_EXEC;
+	pgprot_t prot = kernel_exec_prot();
 	phys_addr_t pa_start = __pa_symbol(__entry_tramp_text_start);
 
 	/* The trampoline is always mapped and can therefore be global */
@@ -723,7 +728,7 @@ static void __init map_kernel(pgd_t *pgdp)
 	 * mapping to install SW breakpoints. Allow this (only) when
 	 * explicitly requested with rodata=off.
 	 */
-	pgprot_t text_prot = rodata_enabled ? PAGE_KERNEL_ROX : PAGE_KERNEL_EXEC;
+	pgprot_t text_prot = kernel_exec_prot();
 
 	/*
 	 * If we have a CPU that supports BTI and a kernel built for
-- 
2.30.2