Commit 1b2b23d8 authored by Tao Guo's avatar Tao Guo Committed by Ingo Molnar
Browse files

x86_64: Work around old GAS bug 



GAS in binutils(2.16.91) could not parse parentheses within
macro parameters unless fully parenthesized, and this is a
workaround to make old gas work without generating below errors:

 arch/x86/kernel/entry_64.S: Assembler messages:
 arch/x86/kernel/entry_64.S:387: Error: too many positional arguments
 arch/x86/kernel/entry_64.S:389: Error: too many positional arguments
 [...]

Signed-off-by: default avatarTao Guo <glorioustao@gmail.com>
Reluctantly-Acked-by: default avatarJan Beulich <jbeulich@novell.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/1348648102-12653-1-git-send-email-glorioustao@gmail.com


[ Jan argues that these old GAS versions are fragile - which is so, but lets give them a chance. ]
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent e26a44a2

arch/x86/include/asm/calling.h

+23 −25
Original line number Diff line number Diff line
@@ -49,38 +49,36 @@ For 32-bit we have the following conventions - kernel is built with 
#include "dwarf2.h"



/*

 * 64-bit system call stack frame layout defines and helpers, for

 * assembly code (note that the seemingly unnecessary parentheses

 * are to prevent cpp from inserting spaces in expressions that get

 * passed to macros):

 * 64-bit system call stack frame layout defines and helpers,

 * for assembly code:

 */



#define R15		  (0)

#define R14		  (8)

#define R13		 (16)

#define R12		 (24)

#define RBP		 (32)

#define RBX		 (40)

#define R15		  0

#define R14		  8

#define R13		 16

#define R12		 24

#define RBP		 32

#define RBX		 40



/* arguments: interrupts/non tracing syscalls only save up to here: */

#define R11		 (48)

#define R10		 (56)

#define R9		 (64)

#define R8		 (72)

#define RAX		 (80)

#define RCX		 (88)

#define RDX		 (96)

#define RSI		(104)

#define RDI		(112)

#define ORIG_RAX	(120)       /* + error_code */

#define R11		 48

#define R10		 56

#define R9		 64

#define R8		 72

#define RAX		 80

#define RCX		 88

#define RDX		 96

#define RSI		104

#define RDI		112

#define ORIG_RAX	120       /* + error_code */

/* end of arguments */



/* cpu exception frame or undefined in case of fast syscall: */

#define RIP		(128)

#define CS		(136)

#define EFLAGS		(144)

#define RSP		(152)

#define SS		(160)

#define RIP		128

#define CS		136

#define EFLAGS		144

#define RSP		152

#define SS		160



#define ARGOFFSET	R11

#define SWFRAME		ORIG_RAX

arch/x86/kernel/entry_64.S

+10 −10
Original line number Diff line number Diff line
@@ -342,15 +342,15 @@ ENDPROC(native_usergs_sysret64) 
	.macro SAVE_ARGS_IRQ

	cld

	/* start from rbp in pt_regs and jump over */

	movq_cfi rdi, RDI-RBP

	movq_cfi rsi, RSI-RBP

	movq_cfi rdx, RDX-RBP

	movq_cfi rcx, RCX-RBP

	movq_cfi rax, RAX-RBP

	movq_cfi  r8,  R8-RBP

	movq_cfi  r9,  R9-RBP

	movq_cfi r10, R10-RBP

	movq_cfi r11, R11-RBP

	movq_cfi rdi, (RDI-RBP)

	movq_cfi rsi, (RSI-RBP)

	movq_cfi rdx, (RDX-RBP)

	movq_cfi rcx, (RCX-RBP)

	movq_cfi rax, (RAX-RBP)

	movq_cfi  r8,  (R8-RBP)

	movq_cfi  r9,  (R9-RBP)

	movq_cfi r10, (R10-RBP)

	movq_cfi r11, (R11-RBP)



	/* Save rbp so that we can unwind from get_irq_regs() */

	movq_cfi rbp, 0
@@ -384,7 +384,7 @@ ENDPROC(native_usergs_sysret64) 
	.endm



ENTRY(save_rest)

	PARTIAL_FRAME 1 REST_SKIP+8

	PARTIAL_FRAME 1 (REST_SKIP+8)

	movq 5*8+16(%rsp), %r11	/* save return address */

	movq_cfi rbx, RBX+16

	movq_cfi rbp, RBP+16

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