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authorVincenzo Frascino <vincenzo.frascino@arm.com>2019-04-15 10:49:37 +0100
committerWill Deacon <will.deacon@arm.com>2019-04-23 18:01:58 +0100
commitaf1b3cf2c2a3f42bbb680812ff1bbd715ac8af69 (patch)
tree67550d4018c6cc1e368214556d744317da53e689 /arch/arm64/kernel/Makefile
parent1255a7341bee6cd96df056ed0c13e44b59023687 (diff)
arm64: compat: Add KUSER_HELPERS config option
When kuser helpers are enabled the kernel maps the relative code at a fixed address (0xffff0000). Making configurable the option to disable them means that the kernel can remove this mapping and any access to this memory area results in a sigfault. Add a KUSER_HELPERS config option that can be used to disable the mapping when it is turned off. This option can be turned off if and only if the applications are designed specifically for the platform and they do not make use of the kuser helpers code. Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> [will: Use IS_ENABLED() instead of #ifdef] Signed-off-by: Will Deacon <will.deacon@arm.com>
Diffstat (limited to 'arch/arm64/kernel/Makefile')
-rw-r--r--arch/arm64/kernel/Makefile3
1 files changed, 2 insertions, 1 deletions
diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile
index c18c34d56029..9e7dcb2c31c7 100644
--- a/arch/arm64/kernel/Makefile
+++ b/arch/arm64/kernel/Makefile
@@ -27,8 +27,9 @@ OBJCOPYFLAGS := --prefix-symbols=__efistub_
$(obj)/%.stub.o: $(obj)/%.o FORCE
$(call if_changed,objcopy)
-obj-$(CONFIG_COMPAT) += sys32.o kuser32.o signal32.o \
+obj-$(CONFIG_COMPAT) += sys32.o signal32.o \
sigreturn32.o sys_compat.o
+obj-$(CONFIG_KUSER_HELPERS) += kuser32.o
obj-$(CONFIG_FUNCTION_TRACER) += ftrace.o entry-ftrace.o
obj-$(CONFIG_MODULES) += module.o
obj-$(CONFIG_ARM64_MODULE_PLTS) += module-plts.o