linux-kernel - [PATCH 4.19 125/148] arm64: drop linker script hack to hide __efistub

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Date:   Fri, 11 Jan 2019 15:15:03 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Nick Desaulniers <ndesaulniers@...gle.com>,
        Ard Biesheuvel <ard.biesheuvel@...aro.org>,
        Will Deacon <will.deacon@....com>
Subject: [PATCH 4.19 125/148] arm64: drop linker script hack to hide __efistub_ symbols

4.19-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Ard Biesheuvel <ard.biesheuvel@...aro.org>

commit dd6846d774693bfa27d7db4dae5ea67dfe373fa1 upstream.

Commit 1212f7a16af4 ("scripts/kallsyms: filter arm64's __efistub_
symbols") updated the kallsyms code to filter out symbols with
the __efistub_ prefix explicitly, so we no longer require the
hack in our linker script to emit them as absolute symbols.

Cc: Nick Desaulniers <ndesaulniers@...gle.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@...aro.org>
Signed-off-by: Will Deacon <will.deacon@....com>
Signed-off-by: Nick Desaulniers <ndesaulniers@...gle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 arch/arm64/kernel/image.h |   46 ++++++++++++++++++----------------------------
 1 file changed, 18 insertions(+), 28 deletions(-)

--- a/arch/arm64/kernel/image.h
+++ b/arch/arm64/kernel/image.h
@@ -76,16 +76,6 @@
 __efistub_stext_offset = stext - _text;
 
 /*
- * Prevent the symbol aliases below from being emitted into the kallsyms
- * table, by forcing them to be absolute symbols (which are conveniently
- * ignored by scripts/kallsyms) rather than section relative symbols.
- * The distinction is only relevant for partial linking, and only for symbols
- * that are defined within a section declaration (which is not the case for
- * the definitions below) so the resulting values will be identical.
- */
-#define KALLSYMS_HIDE(sym)	ABSOLUTE(sym)
-
-/*
  * The EFI stub has its own symbol namespace prefixed by __efistub_, to
  * isolate it from the kernel proper. The following symbols are legally
  * accessed by the stub, so provide some aliases to make them accessible.
@@ -94,28 +84,28 @@ __efistub_stext_offset = stext - _text;
  * linked at. The routines below are all implemented in assembler in a
  * position independent manner
  */
-__efistub_memcmp		= KALLSYMS_HIDE(__pi_memcmp);
-__efistub_memchr		= KALLSYMS_HIDE(__pi_memchr);
-__efistub_memcpy		= KALLSYMS_HIDE(__pi_memcpy);
-__efistub_memmove		= KALLSYMS_HIDE(__pi_memmove);
-__efistub_memset		= KALLSYMS_HIDE(__pi_memset);
-__efistub_strlen		= KALLSYMS_HIDE(__pi_strlen);
-__efistub_strnlen		= KALLSYMS_HIDE(__pi_strnlen);
-__efistub_strcmp		= KALLSYMS_HIDE(__pi_strcmp);
-__efistub_strncmp		= KALLSYMS_HIDE(__pi_strncmp);
-__efistub_strrchr		= KALLSYMS_HIDE(__pi_strrchr);
-__efistub___flush_dcache_area	= KALLSYMS_HIDE(__pi___flush_dcache_area);
+__efistub_memcmp		= __pi_memcmp;
+__efistub_memchr		= __pi_memchr;
+__efistub_memcpy		= __pi_memcpy;
+__efistub_memmove		= __pi_memmove;
+__efistub_memset		= __pi_memset;
+__efistub_strlen		= __pi_strlen;
+__efistub_strnlen		= __pi_strnlen;
+__efistub_strcmp		= __pi_strcmp;
+__efistub_strncmp		= __pi_strncmp;
+__efistub_strrchr		= __pi_strrchr;
+__efistub___flush_dcache_area	= __pi___flush_dcache_area;
 
 #ifdef CONFIG_KASAN
-__efistub___memcpy		= KALLSYMS_HIDE(__pi_memcpy);
-__efistub___memmove		= KALLSYMS_HIDE(__pi_memmove);
-__efistub___memset		= KALLSYMS_HIDE(__pi_memset);
+__efistub___memcpy		= __pi_memcpy;
+__efistub___memmove		= __pi_memmove;
+__efistub___memset		= __pi_memset;
 #endif
 
-__efistub__text			= KALLSYMS_HIDE(_text);
-__efistub__end			= KALLSYMS_HIDE(_end);
-__efistub__edata		= KALLSYMS_HIDE(_edata);
-__efistub_screen_info		= KALLSYMS_HIDE(screen_info);
+__efistub__text			= _text;
+__efistub__end			= _end;
+__efistub__edata		= _edata;
+__efistub_screen_info		= screen_info;
 
 #endif