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From: Ard Biesheuvel <ardb@kernel.org>
To: linux-efi@vger.kernel.org
Cc: Ard Biesheuvel <ardb@kernel.org>,
	nivedita@alum.mit.edu, mingo@kernel.org, lukas@wunner.de,
	atish.patra@wdc.com
Subject: [PATCH 03/19] efi/libstub: Use hidden visiblity for all source files
Date: Mon, 10 Feb 2020 17:02:32 +0100
Message-ID: <20200210160248.4889-4-ardb@kernel.org> (raw)
In-Reply-To: <20200210160248.4889-1-ardb@kernel.org>

Instead of setting the visibility pragma for a small set of symbol
declarations that could result in absolute references that we cannot
support in the stub, declare hidden visibility for all code in the
EFI stub, which is more robust and future proof.

To ensure that the #pragma is taken into account before any other
includes are processed, put it in a header file of its own and
include it via the compiler command line using the -include option.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
 arch/arm64/include/asm/efi.h              | 3 ---
 drivers/firmware/efi/libstub/Makefile     | 2 +-
 drivers/firmware/efi/libstub/arm64-stub.c | 8 +-------
 drivers/firmware/efi/libstub/hidden.h     | 6 ++++++
 4 files changed, 8 insertions(+), 11 deletions(-)

diff --git a/arch/arm64/include/asm/efi.h b/arch/arm64/include/asm/efi.h
index 44531a69d32b..56ae87401a26 100644
--- a/arch/arm64/include/asm/efi.h
+++ b/arch/arm64/include/asm/efi.h
@@ -107,9 +107,6 @@ static inline void free_screen_info(struct screen_info *si)
 {
 }
 
-/* redeclare as 'hidden' so the compiler will generate relative references */
-extern struct screen_info screen_info __attribute__((__visibility__("hidden")));
-
 static inline void efifb_setup_from_dmi(struct screen_info *si, const char *opt)
 {
 }
diff --git a/drivers/firmware/efi/libstub/Makefile b/drivers/firmware/efi/libstub/Makefile
index f14b7636323a..4efdbd711e8e 100644
--- a/drivers/firmware/efi/libstub/Makefile
+++ b/drivers/firmware/efi/libstub/Makefile
@@ -25,7 +25,7 @@ cflags-$(CONFIG_ARM)		:= $(subst $(CC_FLAGS_FTRACE),,$(KBUILD_CFLAGS)) \
 cflags-$(CONFIG_EFI_ARMSTUB)	+= -I$(srctree)/scripts/dtc/libfdt
 
 KBUILD_CFLAGS			:= $(cflags-y) -DDISABLE_BRANCH_PROFILING \
-				   -D__NO_FORTIFY \
+				   -include hidden.h -D__NO_FORTIFY \
 				   $(call cc-option,-ffreestanding) \
 				   $(call cc-option,-fno-stack-protector) \
 				   -D__DISABLE_EXPORTS
diff --git a/drivers/firmware/efi/libstub/arm64-stub.c b/drivers/firmware/efi/libstub/arm64-stub.c
index 2915b44132e6..719d03a64329 100644
--- a/drivers/firmware/efi/libstub/arm64-stub.c
+++ b/drivers/firmware/efi/libstub/arm64-stub.c
@@ -6,17 +6,11 @@
  * Adapted from ARM version by Mark Salter <msalter@redhat.com>
  */
 
-/*
- * To prevent the compiler from emitting GOT-indirected (and thus absolute)
- * references to the section markers, override their visibility as 'hidden'
- */
-#pragma GCC visibility push(hidden)
-#include <asm/sections.h>
-#pragma GCC visibility pop
 
 #include <linux/efi.h>
 #include <asm/efi.h>
 #include <asm/memory.h>
+#include <asm/sections.h>
 #include <asm/sysreg.h>
 
 #include "efistub.h"
diff --git a/drivers/firmware/efi/libstub/hidden.h b/drivers/firmware/efi/libstub/hidden.h
new file mode 100644
index 000000000000..3493b041f419
--- /dev/null
+++ b/drivers/firmware/efi/libstub/hidden.h
@@ -0,0 +1,6 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * To prevent the compiler from emitting GOT-indirected (and thus absolute)
+ * references to any global symbols, override their visibility as 'hidden'
+ */
+#pragma GCC visibility push(hidden)
-- 
2.17.1


  parent reply index

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-10 16:02 [PATCH 00/19] EFI stub early spring cleaning part 2 Ard Biesheuvel
2020-02-10 16:02 ` [PATCH 01/19] efi/libstub/x86: Remove pointless zeroing of apm_bios_info Ard Biesheuvel
2020-02-10 16:02 ` [PATCH 02/19] efi/libstub/x86: Avoid overflowing code32_start on PE entry Ard Biesheuvel
2020-02-10 16:02 ` Ard Biesheuvel [this message]
2020-02-24 23:15   ` [PATCH 03/19] efi/libstub: Use hidden visiblity for all source files Atish Patra
2020-02-24 23:36     ` Ard Biesheuvel
2020-02-25 19:18       ` Atish Patra
2020-02-10 16:02 ` [PATCH 04/19] efi/libstub/arm: Relax FDT alignment requirement Ard Biesheuvel
2020-02-10 16:02 ` [PATCH 05/19] efi/libstub: Move memory map handling and allocation routines to mem.c Ard Biesheuvel
2020-02-10 16:02 ` [PATCH 06/19] efi/libstub: Simplify efi_high_alloc() and rename to efi_allocate_pages() Ard Biesheuvel
2020-02-10 16:02 ` [PATCH 07/19] efi/libstub/x86: Incorporate eboot.c into libstub Ard Biesheuvel
2020-02-10 16:02 ` [PATCH 08/19] efi/libstub: Use consistent type names for file I/O protocols Ard Biesheuvel
2020-02-10 16:02 ` [PATCH 09/19] efi/libstub: Move stub specific declarations into efistub.h Ard Biesheuvel
2020-02-10 16:02 ` [PATCH 10/19] efi/libstub/x86: Permit bootparams struct to be allocated above 4 GB Ard Biesheuvel
2020-02-10 16:02 ` [PATCH 11/19] efi/libstub/x86: Permit cmdline data " Ard Biesheuvel
2020-02-10 16:02 ` [PATCH 12/19] efi/libstub: Move efi_random_alloc() into separate source file Ard Biesheuvel
2020-02-10 16:02 ` [PATCH 13/19] efi/libstub: Move get_dram_base() into arm-stub.c Ard Biesheuvel
2020-02-17  1:17   ` Atish Patra
2020-02-17  8:37     ` Ard Biesheuvel
2020-02-26 23:34       ` Atish Patra
2020-02-27  7:38         ` Ard Biesheuvel
2020-02-27  7:48           ` Atish Patra
2020-02-27  7:50             ` Ard Biesheuvel
2020-02-10 16:02 ` [PATCH 14/19] efi/libstub: Move file I/O support code into separate file Ard Biesheuvel
2020-02-10 16:02 ` [PATCH 15/19] efi/libstub: Rewrite file I/O routine Ard Biesheuvel
2020-02-10 16:02 ` [PATCH 16/19] efi/libstub: Take soft and hard memory limits into account for initrd loading Ard Biesheuvel
2020-02-10 16:02 ` [PATCH 17/19] efi/libstub: Clean up command line parsing routine Ard Biesheuvel
2020-02-10 16:02 ` [PATCH 18/19] efi/libstub: Expose LocateDevicePath boot service Ard Biesheuvel
2020-02-10 16:02 ` [PATCH 19/19] efi/libstub: Make the LoadFile EFI protocol accessible Ard Biesheuvel

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