[RFC PATCH 6/9] arm64: Enable the execmem ROX cache for module text

[Ard Biesheuvel <ardb+git@google.com>]

From: Ard Biesheuvel <ardb@kernel.org>

Wire up the existing support for the execmem ROX cache on arm64, so that
it will be used for module .text and .init.text regions. This will be
relied upon by a subsequent patch in order to allocate those regions
from a single chunk of memory.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
 arch/arm64/Kconfig   |  1 +
 arch/arm64/mm/init.c | 19 ++++++++++++++++++-
 2 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index b3afe0688919..080b97b0bbd5 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -27,6 +27,7 @@ config ARM64
 	select ARCH_HAS_DMA_OPS if XEN
 	select ARCH_HAS_DMA_PREP_COHERENT
 	select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI
+	select ARCH_HAS_EXECMEM_ROX
 	select ARCH_HAS_FAST_MULTIPLIER
 	select ARCH_HAS_FORTIFY_SOURCE
 	select ARCH_HAS_GCOV_PROFILE_ALL
diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
index 97987f850a33..e6c98045046e 100644
--- a/arch/arm64/mm/init.c
+++ b/arch/arm64/mm/init.c
@@ -531,7 +531,8 @@ struct execmem_info __init *execmem_arch_setup(void)
 			[EXECMEM_DEFAULT] = {
 				.start	= start,
 				.end	= end,
-				.pgprot	= PAGE_KERNEL,
+				.pgprot	= PAGE_KERNEL_ROX,
+				.flags	= EXECMEM_ROX_CACHE,
 				.alignment = 1,
 				.fallback_start	= fallback_start,
 				.fallback_end	= fallback_end,
@@ -548,9 +549,25 @@ struct execmem_info __init *execmem_arch_setup(void)
 				.pgprot	= PAGE_KERNEL,
 				.alignment = 1,
 			},
+			[EXECMEM_MODULE_DATA] = {
+				.start	= start,
+				.end	= end,
+				.pgprot	= PAGE_KERNEL,
+				.alignment = 1,
+				.fallback_start	= fallback_start,
+				.fallback_end	= fallback_end,
+			},
 		},
 	};
 
+	if (!system_supports_bbml2_noabort())
+		execmem_info.ranges[EXECMEM_DEFAULT].flags |= EXECMEM_NO_HUGE_VMAP;
+
 	return &execmem_info;
 }
+
+void execmem_fill_trapping_insns(void *ptr, size_t size)
+{
+	memset32(ptr, AARCH64_BREAK_FAULT, size / sizeof(__le32));
+}
 #endif /* CONFIG_EXECMEM */
-- 
2.55.0.860.g4b6b3295ed-goog