linux-kernel - [PATCH v3 03/12] Revert "x86/extable: Macrofy inline assembly code to work around GCC inlining bugs"

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Message-Id: <1545062607-8599-4-git-send-email-yamada.masahiro@socionext.com>
Date:   Tue, 18 Dec 2018 01:03:18 +0900
From:   Masahiro Yamada <yamada.masahiro@...ionext.com>
To:     x86@...nel.org, Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        "H . Peter Anvin" <hpa@...or.com>
Cc:     Richard Biener <rguenther@...e.de>,
        Segher Boessenkool <segher@...nel.crashing.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Juergen Gross <jgross@...e.com>,
        Josh Poimboeuf <jpoimboe@...hat.com>,
        Kees Cook <keescook@...omium.org>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Masahiro Yamada <yamada.masahiro@...ionext.com>,
        Yonghong Song <yhs@...com>, linux-kernel@...r.kernel.org,
        Arnaldo Carvalho de Melo <acme@...hat.com>,
        Nadav Amit <namit@...are.com>, Jann Horn <jannh@...gle.com>
Subject: [PATCH v3 03/12] Revert "x86/extable: Macrofy inline assembly code to work around GCC inlining bugs"

This reverts commit 0474d5d9d2f7f3b11262f7bf87d0e7314ead9200.

The in-kernel workarounds will be replaced with GCC's new
"asm inline" syntax.

Signed-off-by: Masahiro Yamada <yamada.masahiro@...ionext.com>
---

I blindly reverted here, but I will clean it up
in a different way later.

 arch/x86/include/asm/asm.h | 53 +++++++++++++++++++++++++++++-----------------
 arch/x86/kernel/macros.S   |  1 -
 2 files changed, 33 insertions(+), 21 deletions(-)

diff --git a/arch/x86/include/asm/asm.h b/arch/x86/include/asm/asm.h
index 21b0867..6467757b 100644
--- a/arch/x86/include/asm/asm.h
+++ b/arch/x86/include/asm/asm.h
@@ -120,25 +120,12 @@
 /* Exception table entry */
 #ifdef __ASSEMBLY__
 # define _ASM_EXTABLE_HANDLE(from, to, handler)			\
-	ASM_EXTABLE_HANDLE from to handler
-
-.macro ASM_EXTABLE_HANDLE from:req to:req handler:req
-	.pushsection "__ex_table","a"
-	.balign 4
-	.long (\from) - .
-	.long (\to) - .
-	.long (\handler) - .
+	.pushsection "__ex_table","a" ;				\
+	.balign 4 ;						\
+	.long (from) - . ;					\
+	.long (to) - . ;					\
+	.long (handler) - . ;					\
 	.popsection
-.endm
-#else /* __ASSEMBLY__ */
-
-# define _ASM_EXTABLE_HANDLE(from, to, handler)			\
-	"ASM_EXTABLE_HANDLE from=" #from " to=" #to		\
-	" handler=\"" #handler "\"\n\t"
-
-/* For C file, we already have NOKPROBE_SYMBOL macro */
-
-#endif /* __ASSEMBLY__ */
 
 # define _ASM_EXTABLE(from, to)					\
 	_ASM_EXTABLE_HANDLE(from, to, ex_handler_default)
@@ -161,7 +148,6 @@
 	_ASM_PTR (entry);					\
 	.popsection
 
-#ifdef __ASSEMBLY__
 .macro ALIGN_DESTINATION
 	/* check for bad alignment of destination */
 	movl %edi,%ecx
@@ -185,7 +171,34 @@
 	_ASM_EXTABLE_UA(100b, 103b)
 	_ASM_EXTABLE_UA(101b, 103b)
 	.endm
-#endif /* __ASSEMBLY__ */
+
+#else
+# define _EXPAND_EXTABLE_HANDLE(x) #x
+# define _ASM_EXTABLE_HANDLE(from, to, handler)			\
+	" .pushsection \"__ex_table\",\"a\"\n"			\
+	" .balign 4\n"						\
+	" .long (" #from ") - .\n"				\
+	" .long (" #to ") - .\n"				\
+	" .long (" _EXPAND_EXTABLE_HANDLE(handler) ") - .\n"	\
+	" .popsection\n"
+
+# define _ASM_EXTABLE(from, to)					\
+	_ASM_EXTABLE_HANDLE(from, to, ex_handler_default)
+
+# define _ASM_EXTABLE_UA(from, to)				\
+	_ASM_EXTABLE_HANDLE(from, to, ex_handler_uaccess)
+
+# define _ASM_EXTABLE_FAULT(from, to)				\
+	_ASM_EXTABLE_HANDLE(from, to, ex_handler_fault)
+
+# define _ASM_EXTABLE_EX(from, to)				\
+	_ASM_EXTABLE_HANDLE(from, to, ex_handler_ext)
+
+# define _ASM_EXTABLE_REFCOUNT(from, to)			\
+	_ASM_EXTABLE_HANDLE(from, to, ex_handler_refcount)
+
+/* For C file, we already have NOKPROBE_SYMBOL macro */
+#endif
 
 #ifndef __ASSEMBLY__
 /*
diff --git a/arch/x86/kernel/macros.S b/arch/x86/kernel/macros.S
index 7baa40d..71d8b71 100644
--- a/arch/x86/kernel/macros.S
+++ b/arch/x86/kernel/macros.S
@@ -11,4 +11,3 @@
 #include <asm/alternative-asm.h>
 #include <asm/bug.h>
 #include <asm/paravirt.h>
-#include <asm/asm.h>
-- 
2.7.4