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From:   Jian Cai <caij2003@gmail.com>
Cc:     caij2003@gmail.com, jiancai@google.com, ndesaulniers@google.com,
        manojgupta@google.com, sedat.dilek@gmail.com,
        Brian Gerst <brgerst@gmail.com>,
        Arvind Sankar <nivedita@alum.mit.edu>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
        Andy Lutomirski <luto@kernel.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Alexandre Chartre <alexandre.chartre@oracle.com>,
        linux-kernel@vger.kernel.org, clang-built-linux@googlegroups.com
Subject: [PATCH] x86/entry: add compatibility with IAS
Date:   Mon, 13 Jul 2020 15:40:18 -0700
Message-Id: <20200713224020.1297154-1-caij2003@gmail.com>
In-Reply-To: <20200713012428.1039487-1-caij2003@gmail.com>
References: <20200713012428.1039487-1-caij2003@gmail.com>
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Clang's integrated assembler does not allow symbols with non-absolute
values to be reassigned. This patch allows the affected code to be
compatible with IAS.

Link: https://github.com/ClangBuiltLinux/linux/issues/1043
Reported-by: Nick Desaulniers <ndesaulniers@google.com>
Reported-by: Sedat Dilek <sedat.dilek@gmail.com>
Suggested-by: Nick Desaulniers <ndesaulniers@google.com>
Suggested-by: Brian Gerst <brgerst@gmail.com>
Suggested-by: Arvind Sankar <nivedita@alum.mit.edu>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Signed-off-by: Jian Cai <caij2003@gmail.com>
---
 arch/x86/include/asm/idtentry.h | 14 ++++++--------
 1 file changed, 6 insertions(+), 8 deletions(-)

diff --git a/arch/x86/include/asm/idtentry.h b/arch/x86/include/asm/idtentry.h
index f3d70830bf2a..5efaaed34eda 100644
--- a/arch/x86/include/asm/idtentry.h
+++ b/arch/x86/include/asm/idtentry.h
@@ -469,16 +469,15 @@ __visible noinstr void func(struct pt_regs *regs,			\
 	.align 8
 SYM_CODE_START(irq_entries_start)
     vector=FIRST_EXTERNAL_VECTOR
-    pos = .
     .rept (FIRST_SYSTEM_VECTOR - FIRST_EXTERNAL_VECTOR)
 	UNWIND_HINT_IRET_REGS
+0 :
 	.byte	0x6a, vector
 	jmp	asm_common_interrupt
 	nop
 	/* Ensure that the above is 8 bytes max */
-	. = pos + 8
-    pos=pos+8
-    vector=vector+1
+	. = 0b + 8
+	vector = vector+1
     .endr
 SYM_CODE_END(irq_entries_start)
 
@@ -486,16 +485,15 @@ SYM_CODE_END(irq_entries_start)
 	.align 8
 SYM_CODE_START(spurious_entries_start)
     vector=FIRST_SYSTEM_VECTOR
-    pos = .
     .rept (NR_VECTORS - FIRST_SYSTEM_VECTOR)
 	UNWIND_HINT_IRET_REGS
+0 :
 	.byte	0x6a, vector
 	jmp	asm_spurious_interrupt
 	nop
 	/* Ensure that the above is 8 bytes max */
-	. = pos + 8
-    pos=pos+8
-    vector=vector+1
+	. = 0b + 8
+	vector = vector+1
     .endr
 SYM_CODE_END(spurious_entries_start)
 #endif
-- 
2.27.0.383.g050319c2ae-goog