[2/3] efi/libstub: arm64: force 'hidden' visibility for section markers

Message ID 20170518090953.32628-3-ard.biesheuvel@linaro.org
State New
Headers show
Series
  • efi: arm64: use -fpie for building the stub
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Commit Message

Ard Biesheuvel May 18, 2017, 9:09 a.m.
To prevent the compiler from emitting absolute references to the section
markers when running in PIC mode, override the visibility to 'hidden' for
all contents of asm/sections.h

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>

---
 drivers/firmware/efi/libstub/arm64-stub.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

-- 
2.9.3

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Comments

Matthias Kaehlcke June 8, 2017, 7:07 p.m. | #1
El Thu, May 18, 2017 at 10:09:52AM +0100 Ard Biesheuvel ha dit:

> To prevent the compiler from emitting absolute references to the section

> markers when running in PIC mode, override the visibility to 'hidden' for

> all contents of asm/sections.h

> 

> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>


Tested-by: Matthias Kaehlcke <mka@chromium.org>

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Patch hide | download patch | download mbox

diff --git a/drivers/firmware/efi/libstub/arm64-stub.c b/drivers/firmware/efi/libstub/arm64-stub.c
index b4c2589d7c91..f7a6970e9abc 100644
--- a/drivers/firmware/efi/libstub/arm64-stub.c
+++ b/drivers/firmware/efi/libstub/arm64-stub.c
@@ -9,9 +9,17 @@ 
  * published by the Free Software Foundation.
  *
  */
+
+/*
+ * 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/sections.h>
 #include <asm/sysreg.h>
 
 #include "efistub.h"