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From:   Arvind Sankar <nivedita@alum.mit.edu>
To:     Ard Biesheuvel <ardb@kernel.org>
Cc:     linux-efi@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        x86@kernel.org, Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        linux-kernel@vger.kernel.org
Subject: [PATCH 2/5] efi/libstub: Factor out relocation checking
Date:   Wed, 15 Apr 2020 18:15:17 -0400
Message-Id: <20200415221520.2692512-3-nivedita@alum.mit.edu>
In-Reply-To: <20200415221520.2692512-1-nivedita@alum.mit.edu>
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In preparation for using STUBCOPY for x86 as well, which doesn't require
relocation checking, move the checking code into its own variable so it
can be left out for x86.

Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
---
 drivers/firmware/efi/libstub/Makefile | 30 ++++++++++++++++-----------
 1 file changed, 18 insertions(+), 12 deletions(-)

diff --git a/drivers/firmware/efi/libstub/Makefile b/drivers/firmware/efi/libstub/Makefile
index 45ffe0822df1..e5e76677f2da 100644
--- a/drivers/firmware/efi/libstub/Makefile
+++ b/drivers/firmware/efi/libstub/Makefile
@@ -80,6 +80,15 @@ STUBCOPY_FLAGS-$(CONFIG_ARM64)	+= --prefix-alloc-sections=.init \
 				   --prefix-symbols=__efistub_
 STUBCOPY_RELOC-$(CONFIG_ARM64)	:= R_AARCH64_ABS
 
+#
+# ARM discards the .data section because it disallows r/w data in the
+# decompressor. So move our .data to .data.efistub and .bss to .bss.efistub,
+# which are preserved explicitly by the decompressor linker script.
+#
+STUBCOPY_FLAGS-$(CONFIG_ARM)	+= --rename-section .data=.data.efistub	\
+				   --rename-section .bss=.bss.efistub,load,alloc
+STUBCOPY_RELOC-$(CONFIG_ARM)	:= R_ARM_ABS
+
 $(obj)/%.stub.o: $(obj)/%.o FORCE
 	$(call if_changed,stubcopy)
 
@@ -89,20 +98,17 @@ $(obj)/%.stub.o: $(obj)/%.o FORCE
 # such relocations. If none are found, regenerate the output object, but
 # this time, use objcopy and leave all sections in place.
 #
-quiet_cmd_stubcopy = STUBCPY $@
-      cmd_stubcopy =							\
+
+cmd_stubrelocs_check-y = /bin/true
+
+cmd_stubrelocs_check-$(CONFIG_EFI_ARMSTUB) =				\
 	$(STRIP) --strip-debug -o $@ $<;				\
 	if $(OBJDUMP) -r $@ | grep $(STUBCOPY_RELOC-y); then		\
 		echo "$@: absolute symbol references not allowed in the EFI stub" >&2; \
 		/bin/false;						\
-	fi;								\
-	$(OBJCOPY) $(STUBCOPY_FLAGS-y) $< $@
+	fi
 
-#
-# ARM discards the .data section because it disallows r/w data in the
-# decompressor. So move our .data to .data.efistub and .bss to .bss.efistub,
-# which are preserved explicitly by the decompressor linker script.
-#
-STUBCOPY_FLAGS-$(CONFIG_ARM)	+= --rename-section .data=.data.efistub	\
-				   --rename-section .bss=.bss.efistub,load,alloc
-STUBCOPY_RELOC-$(CONFIG_ARM)	:= R_ARM_ABS
+quiet_cmd_stubcopy = STUBCPY $@
+      cmd_stubcopy =							\
+	$(cmd_stubrelocs_check-y);					\
+	$(OBJCOPY) $(STUBCOPY_FLAGS-y) $< $@
-- 
2.24.1