C6X: build infrastructure

Original port to early 2.6 kernel using TI COFF toolchain.
Brought up to date by Mark Salter <msalter@redhat.com>

Signed-off-by: Aurelien Jacquiot <a-jacquiot@ti.com>
Signed-off-by: Mark Salter <msalter@redhat.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>

1 files changed, 803 insertions, 0 deletions

diff --git a/arch/c6x/kernel/entry.S b/arch/c6x/kernel/entry.S
new file mode 100644
index 000000000000..3e977ccda827
--- /dev/null
+++ b/arch/c6x/kernel/entry.S
@@ -0,0 +1,803 @@
+;
+;  Port on Texas Instruments TMS320C6x architecture
+;
+;  Copyright (C) 2004-2011 Texas Instruments Incorporated
+;  Author: Aurelien Jacquiot (aurelien.jacquiot@virtuallogix.com)
+;  Updated for 2.6.34: Mark Salter <msalter@redhat.com>
+;
+;  This program is free software; you can redistribute it and/or modify
+;  it under the terms of the GNU General Public License version 2 as
+;  published by the Free Software Foundation.
+;
+
+#include <linux/sys.h>
+#include <linux/linkage.h>
+#include <asm/thread_info.h>
+#include <asm/asm-offsets.h>
+#include <asm/unistd.h>
+#include <asm/errno.h>
+
+; Registers naming
+#define DP	B14
+#define SP	B15
+
+#ifndef CONFIG_PREEMPT
+#define resume_kernel restore_all
+#endif
+
+	.altmacro
+
+	.macro MASK_INT reg
+	MVC	.S2	CSR,reg
+	CLR	.S2	reg,0,0,reg
+	MVC	.S2	reg,CSR
+	.endm
+
+	.macro UNMASK_INT reg
+	MVC	.S2	CSR,reg
+	SET	.S2	reg,0,0,reg
+	MVC	.S2	reg,CSR
+	.endm
+
+	.macro GET_THREAD_INFO reg
+	SHR	.S1X	SP,THREAD_SHIFT,reg
+	SHL	.S1	reg,THREAD_SHIFT,reg
+	.endm
+
+	;;
+	;;  This defines the normal kernel pt_regs layout.
+	;;
+	.macro SAVE_ALL __rp __tsr
+	STW	.D2T2	B0,*SP--[2]		; save original B0
+	MVKL	.S2	current_ksp,B0
+	MVKH	.S2	current_ksp,B0
+	LDW	.D2T2	*B0,B1			; KSP
+
+	NOP	3
+	STW	.D2T2	B1,*+SP[1]		; save original B1
+	XOR	.D2	SP,B1,B0		; (SP ^ KSP)
+	LDW	.D2T2	*+SP[1],B1		; restore B0/B1
+	LDW	.D2T2	*++SP[2],B0
+	SHR	.S2	B0,THREAD_SHIFT,B0	; 0 if already using kstack
+  [B0]	STDW	.D2T2	SP:DP,*--B1[1]		; user: save user sp/dp kstack
+  [B0]	MV	.S2	B1,SP			;    and switch to kstack
+||[!B0] STDW	.D2T2	SP:DP,*--SP[1]		; kernel: save on current stack
+
+	SUBAW	.D2	SP,2,SP
+
+	ADD	.D1X	SP,-8,A15
+ ||	STDW	.D2T1	A15:A14,*SP--[16]	; save A15:A14
+
+	STDW	.D2T2	B13:B12,*SP--[1]
+ ||	STDW	.D1T1	A13:A12,*A15--[1]
+ ||	MVC	.S2	__rp,B13
+
+	STDW	.D2T2	B11:B10,*SP--[1]
+ ||	STDW	.D1T1	A11:A10,*A15--[1]
+ ||	MVC	.S2	CSR,B12
+
+	STDW	.D2T2	B9:B8,*SP--[1]
+ ||	STDW	.D1T1	A9:A8,*A15--[1]
+ ||	MVC	.S2	RILC,B11
+	STDW	.D2T2	B7:B6,*SP--[1]
+ ||	STDW	.D1T1	A7:A6,*A15--[1]
+ ||	MVC	.S2	ILC,B10
+
+	STDW	.D2T2	B5:B4,*SP--[1]
+ ||	STDW	.D1T1	A5:A4,*A15--[1]
+
+	STDW	.D2T2	B3:B2,*SP--[1]
+ ||	STDW	.D1T1	A3:A2,*A15--[1]
+ ||	MVC	.S2	__tsr,B5
+
+	STDW	.D2T2	B1:B0,*SP--[1]
+ ||	STDW	.D1T1	A1:A0,*A15--[1]
+ ||	MV	.S1X	B5,A5
+
+	STDW	.D2T2	B31:B30,*SP--[1]
+ ||	STDW	.D1T1	A31:A30,*A15--[1]
+	STDW	.D2T2	B29:B28,*SP--[1]
+ ||	STDW	.D1T1	A29:A28,*A15--[1]
+	STDW	.D2T2	B27:B26,*SP--[1]
+ ||	STDW	.D1T1	A27:A26,*A15--[1]
+	STDW	.D2T2	B25:B24,*SP--[1]
+ ||	STDW	.D1T1	A25:A24,*A15--[1]
+	STDW	.D2T2	B23:B22,*SP--[1]
+ ||	STDW	.D1T1	A23:A22,*A15--[1]
+	STDW	.D2T2	B21:B20,*SP--[1]
+ ||	STDW	.D1T1	A21:A20,*A15--[1]
+	STDW	.D2T2	B19:B18,*SP--[1]
+ ||	STDW	.D1T1	A19:A18,*A15--[1]
+	STDW	.D2T2	B17:B16,*SP--[1]
+ ||	STDW	.D1T1	A17:A16,*A15--[1]
+
+	STDW	.D2T2	B13:B12,*SP--[1]	; save PC and CSR
+
+	STDW	.D2T2	B11:B10,*SP--[1]	; save RILC and ILC
+	STDW	.D2T1	A5:A4,*SP--[1]		; save TSR and orig A4
+
+	;; We left an unused word on the stack just above pt_regs.
+	;; It is used to save whether or not this frame is due to
+	;; a syscall. It is cleared here, but the syscall handler
+	;; sets it to a non-zero value.
+	MVK	.L2	0,B1
+	STW	.D2T2	B1,*+SP(REGS__END+8)	; clear syscall flag
+	.endm
+
+	.macro RESTORE_ALL __rp __tsr
+	LDDW	.D2T2	*++SP[1],B9:B8		; get TSR (B9)
+	LDDW	.D2T2	*++SP[1],B11:B10	; get RILC (B11) and ILC (B10)
+	LDDW	.D2T2	*++SP[1],B13:B12	; get PC (B13) and CSR (B12)
+
+	ADDAW	.D1X	SP,30,A15
+
+	LDDW	.D1T1	*++A15[1],A17:A16
+ ||	LDDW	.D2T2	*++SP[1],B17:B16
+	LDDW	.D1T1	*++A15[1],A19:A18
+ ||	LDDW	.D2T2	*++SP[1],B19:B18
+	LDDW	.D1T1	*++A15[1],A21:A20
+ ||	LDDW	.D2T2	*++SP[1],B21:B20
+	LDDW	.D1T1	*++A15[1],A23:A22
+ ||	LDDW	.D2T2	*++SP[1],B23:B22
+	LDDW	.D1T1	*++A15[1],A25:A24
+ ||	LDDW	.D2T2	*++SP[1],B25:B24
+	LDDW	.D1T1	*++A15[1],A27:A26
+ ||	LDDW	.D2T2	*++SP[1],B27:B26
+	LDDW	.D1T1	*++A15[1],A29:A28
+ ||	LDDW	.D2T2	*++SP[1],B29:B28
+	LDDW	.D1T1	*++A15[1],A31:A30
+ ||	LDDW	.D2T2	*++SP[1],B31:B30
+
+	LDDW	.D1T1	*++A15[1],A1:A0
+ ||	LDDW	.D2T2	*++SP[1],B1:B0
+
+	LDDW	.D1T1	*++A15[1],A3:A2
+ ||	LDDW	.D2T2	*++SP[1],B3:B2
+ ||	MVC	.S2	B9,__tsr
+	LDDW	.D1T1	*++A15[1],A5:A4
+ ||	LDDW	.D2T2	*++SP[1],B5:B4
+ ||	MVC	.S2	B11,RILC
+	LDDW	.D1T1	*++A15[1],A7:A6
+ ||	LDDW	.D2T2	*++SP[1],B7:B6
+ ||	MVC	.S2	B10,ILC
+
+	LDDW	.D1T1	*++A15[1],A9:A8
+ ||	LDDW	.D2T2	*++SP[1],B9:B8
+ ||	MVC	.S2	B13,__rp
+
+	LDDW	.D1T1	*++A15[1],A11:A10
+ ||	LDDW	.D2T2	*++SP[1],B11:B10
+ ||	MVC	.S2	B12,CSR
+
+	LDDW	.D1T1	*++A15[1],A13:A12
+ ||	LDDW	.D2T2	*++SP[1],B13:B12
+
+	MV	.D2X	A15,SP
+ ||	MVKL	.S1	current_ksp,A15
+	MVKH	.S1	current_ksp,A15
+ ||	ADDAW	.D1X	SP,6,A14
+	STW	.D1T1	A14,*A15	; save kernel stack pointer
+
+	LDDW	.D2T1	*++SP[1],A15:A14
+
+	B	.S2	__rp		; return from interruption
+	LDDW	.D2T2	*+SP[1],SP:DP
+	NOP	4
+	.endm
+
+	.section .text
+
+	;;
+	;; Jump to schedule() then return to ret_from_exception
+	;;
+_reschedule:
+#ifdef CONFIG_C6X_BIG_KERNEL
+	MVKL	.S1	schedule,A0
+	MVKH	.S1	schedule,A0
+	B	.S2X	A0
+#else
+	B	.S1	schedule
+#endif
+	ADDKPC	.S2	ret_from_exception,B3,4
+
+	;;
+	;; Called before syscall handler when process is being debugged
+	;;
+tracesys_on:
+#ifdef CONFIG_C6X_BIG_KERNEL
+	MVKL	.S1	syscall_trace_entry,A0
+	MVKH	.S1	syscall_trace_entry,A0
+	B	.S2X	A0
+#else
+	B	.S1	syscall_trace_entry
+#endif
+	ADDKPC	.S2	ret_from_syscall_trace,B3,3
+	ADD	.S1X	8,SP,A4
+
+ret_from_syscall_trace:
+	;; tracing returns (possibly new) syscall number
+	MV	.D2X	A4,B0
+ ||	MVK	.S2	__NR_syscalls,B1
+	CMPLTU	.L2	B0,B1,B1
+
+ [!B1]	BNOP	.S2	ret_from_syscall_function,5
+ ||	MVK	.S1	-ENOSYS,A4
+
+	;; reload syscall args from (possibly modified) stack frame
+	;; and get syscall handler addr from sys_call_table:
+	LDW	.D2T2	*+SP(REGS_B4+8),B4
+ ||	MVKL	.S2	sys_call_table,B1
+	LDW	.D2T1	*+SP(REGS_A6+8),A6
+ ||	MVKH	.S2	sys_call_table,B1
+	LDW	.D2T2	*+B1[B0],B0
+ ||	MVKL	.S2	ret_from_syscall_function,B3
+	LDW	.D2T2	*+SP(REGS_B6+8),B6
+ ||	MVKH	.S2	ret_from_syscall_function,B3
+	LDW	.D2T1	*+SP(REGS_A8+8),A8
+	LDW	.D2T2	*+SP(REGS_B8+8),B8
+	NOP
+	; B0 = sys_call_table[__NR_*]
+	BNOP	.S2	B0,5			; branch to syscall handler
+ ||	LDW	.D2T1	*+SP(REGS_ORIG_A4+8),A4
+
+syscall_exit_work:
+	AND	.D1	_TIF_SYSCALL_TRACE,A2,A0
+ [!A0]	BNOP	.S1	work_pending,5
+ [A0]	B	.S2	syscall_trace_exit
+	ADDKPC	.S2	resume_userspace,B3,1
+	MVC	.S2	CSR,B1
+	SET	.S2	B1,0,0,B1
+	MVC	.S2	B1,CSR		; enable ints
+
+work_pending:
+	AND	.D1	_TIF_NEED_RESCHED,A2,A0
+ [!A0]	BNOP	.S1	work_notifysig,5
+
+work_resched:
+#ifdef CONFIG_C6X_BIG_KERNEL
+	MVKL	.S1	schedule,A1
+	MVKH	.S1	schedule,A1
+	B	.S2X	A1
+#else
+	B	.S2	schedule
+#endif
+	ADDKPC	.S2	work_rescheduled,B3,4
+work_rescheduled:
+	;; make sure we don't miss an interrupt setting need_resched or
+	;; sigpending between sampling and the rti
+	MASK_INT B2
+	GET_THREAD_INFO A12
+	LDW	.D1T1	*+A12(THREAD_INFO_FLAGS),A2
+	MVK	.S1	_TIF_WORK_MASK,A1
+	MVK	.S1	_TIF_NEED_RESCHED,A3
+	NOP	2
+	AND	.D1	A1,A2,A0
+ ||	AND	.S1	A3,A2,A1
+ [!A0]	BNOP	.S1	restore_all,5
+ [A1]	BNOP	.S1	work_resched,5
+
+work_notifysig:
+	B	.S2	do_notify_resume
+	LDW	.D2T1	*+SP(REGS__END+8),A6 ; syscall flag
+	ADDKPC	.S2	resume_userspace,B3,1
+	ADD	.S1X	8,SP,A4		; pt_regs pointer is first arg
+	MV	.D2X	A2,B4		; thread_info flags is second arg
+
+	;;
+	;; On C64x+, the return way from exception and interrupt
+	;; is a little bit different
+	;;
+ENTRY(ret_from_exception)
+#ifdef CONFIG_PREEMPT
+	MASK_INT B2
+#endif
+
+ENTRY(ret_from_interrupt)
+	;;
+	;; Check if we are comming from user mode.
+	;;
+	LDW	.D2T2	*+SP(REGS_TSR+8),B0
+	MVK	.S2	0x40,B1
+	NOP	3
+	AND	.D2	B0,B1,B0
+ [!B0]	BNOP	.S2	resume_kernel,5
+
+resume_userspace:
+	;; make sure we don't miss an interrupt setting need_resched or
+	;; sigpending between sampling and the rti
+	MASK_INT B2
+	GET_THREAD_INFO A12
+	LDW	.D1T1	*+A12(THREAD_INFO_FLAGS),A2
+	MVK	.S1	_TIF_WORK_MASK,A1
+	MVK	.S1	_TIF_NEED_RESCHED,A3
+	NOP	2
+	AND	.D1	A1,A2,A0
+ [A0]	BNOP	.S1	work_pending,5
+	BNOP	.S1	restore_all,5
+
+	;;
+	;; System call handling
+	;; B0 = syscall number (in sys_call_table)
+	;; A4,B4,A6,B6,A8,B8 = arguments of the syscall function
+	;; A4 is the return value register
+	;;
+system_call_saved:
+	MVK	.L2	1,B2
+	STW	.D2T2	B2,*+SP(REGS__END+8)	; set syscall flag
+	MVC	.S2	B2,ECR			; ack the software exception
+
+	UNMASK_INT B2			; re-enable global IT
+
+system_call_saved_noack:
+	;; Check system call number
+	MVK	.S2	__NR_syscalls,B1
+#ifdef CONFIG_C6X_BIG_KERNEL
+ ||	MVKL	.S1	sys_ni_syscall,A0
+#endif
+	CMPLTU	.L2	B0,B1,B1
+#ifdef CONFIG_C6X_BIG_KERNEL
+ ||	MVKH	.S1	sys_ni_syscall,A0
+#endif
+
+	;; Check for ptrace
+	GET_THREAD_INFO A12
+
+#ifdef CONFIG_C6X_BIG_KERNEL
+ [!B1]	B	.S2X	A0
+#else
+ [!B1]	B	.S2	sys_ni_syscall
+#endif
+ [!B1]	ADDKPC	.S2	ret_from_syscall_function,B3,4
+
+	;; Get syscall handler addr from sys_call_table
+	;; call tracesys_on or call syscall handler
+	LDW	.D1T1	*+A12(THREAD_INFO_FLAGS),A2
+ ||	MVKL	.S2	sys_call_table,B1
+	MVKH	.S2	sys_call_table,B1
+	LDW	.D2T2	*+B1[B0],B0
+	NOP	2
+	; A2 = thread_info flags
+	AND	.D1	_TIF_SYSCALL_TRACE,A2,A2
+ [A2]	BNOP	.S1	tracesys_on,5
+	;; B0 = _sys_call_table[__NR_*]
+	B	.S2	B0
+	ADDKPC	.S2	ret_from_syscall_function,B3,4
+
+ret_from_syscall_function:
+	STW	.D2T1	A4,*+SP(REGS_A4+8)	; save return value in A4
+						; original A4 is in orig_A4
+syscall_exit:
+	;; make sure we don't miss an interrupt setting need_resched or
+	;; sigpending between sampling and the rti
+	MASK_INT B2
+	LDW	.D1T1	*+A12(THREAD_INFO_FLAGS),A2
+	MVK	.S1	_TIF_ALLWORK_MASK,A1
+	NOP	3
+	AND	.D1	A1,A2,A2 ; check for work to do
+ [A2]	BNOP	.S1	syscall_exit_work,5
+
+restore_all:
+	RESTORE_ALL NRP,NTSR
+
+	;;
+	;; After a fork we jump here directly from resume,
+	;; so that A4 contains the previous task structure.
+	;;
+ENTRY(ret_from_fork)
+#ifdef CONFIG_C6X_BIG_KERNEL
+	MVKL	.S1	schedule_tail,A0
+	MVKH	.S1	schedule_tail,A0
+	B	.S2X	A0
+#else
+	B	.S2	schedule_tail
+#endif
+	ADDKPC	.S2	ret_from_fork_2,B3,4
+ret_from_fork_2:
+	;; return 0 in A4 for child process
+	GET_THREAD_INFO A12
+	BNOP	.S2	syscall_exit,3
+	MVK	.L2	0,B0
+	STW	.D2T2	B0,*+SP(REGS_A4+8)
+ENDPROC(ret_from_fork)
+
+	;;
+	;; These are the interrupt handlers, responsible for calling __do_IRQ()
+	;; int6 is used for syscalls (see _system_call entry)
+	;;
+	.macro SAVE_ALL_INT
+	SAVE_ALL IRP,ITSR
+	.endm
+
+	.macro CALL_INT int
+#ifdef CONFIG_C6X_BIG_KERNEL
+	MVKL	.S1	c6x_do_IRQ,A0
+	MVKH	.S1	c6x_do_IRQ,A0
+	BNOP	.S2X	A0,1
+	MVK	.S1	int,A4
+	ADDAW	.D2	SP,2,B4
+	MVKL	.S2	ret_from_interrupt,B3
+	MVKH	.S2	ret_from_interrupt,B3
+#else
+	CALLP   .S2	c6x_do_IRQ,B3
+ ||	MVK	.S1	int,A4
+ ||	ADDAW	.D2	SP,2,B4
+	B	.S1	ret_from_interrupt
+	NOP	5
+#endif
+	.endm
+
+ENTRY(_int4_handler)
+	SAVE_ALL_INT
+	CALL_INT 4
+ENDPROC(_int4_handler)
+
+ENTRY(_int5_handler)
+	SAVE_ALL_INT
+	CALL_INT 5
+ENDPROC(_int5_handler)
+
+ENTRY(_int6_handler)
+	SAVE_ALL_INT
+	CALL_INT 6
+ENDPROC(_int6_handler)
+
+ENTRY(_int7_handler)
+	SAVE_ALL_INT
+	CALL_INT 7
+ENDPROC(_int7_handler)
+
+ENTRY(_int8_handler)
+	SAVE_ALL_INT
+	CALL_INT 8
+ENDPROC(_int8_handler)
+
+ENTRY(_int9_handler)
+	SAVE_ALL_INT
+	CALL_INT 9
+ENDPROC(_int9_handler)
+
+ENTRY(_int10_handler)
+	SAVE_ALL_INT
+	CALL_INT 10
+ENDPROC(_int10_handler)
+
+ENTRY(_int11_handler)
+	SAVE_ALL_INT
+	CALL_INT 11
+ENDPROC(_int11_handler)
+
+ENTRY(_int12_handler)
+	SAVE_ALL_INT
+	CALL_INT 12
+ENDPROC(_int12_handler)
+
+ENTRY(_int13_handler)
+	SAVE_ALL_INT
+	CALL_INT 13
+ENDPROC(_int13_handler)
+
+ENTRY(_int14_handler)
+	SAVE_ALL_INT
+	CALL_INT 14
+ENDPROC(_int14_handler)
+
+ENTRY(_int15_handler)
+	SAVE_ALL_INT
+	CALL_INT 15
+ENDPROC(_int15_handler)
+
+	;;
+	;; Handler for uninitialized and spurious interrupts
+	;;
+ENTRY(_bad_interrupt)
+	B	.S2	IRP
+	NOP	5
+ENDPROC(_bad_interrupt)
+
+	;;
+	;; Entry for NMI/exceptions/syscall
+	;;
+ENTRY(_nmi_handler)
+	SAVE_ALL NRP,NTSR
+
+	MVC	.S2	EFR,B2
+	CMPEQ	.L2	1,B2,B2
+ ||	MVC	.S2	TSR,B1
+	CLR	.S2	B1,10,10,B1
+	MVC	.S2	B1,TSR
+#ifdef CONFIG_C6X_BIG_KERNEL
+ [!B2]	MVKL	.S1	process_exception,A0
+ [!B2]	MVKH	.S1	process_exception,A0
+ [!B2]	B	.S2X	A0
+#else
+ [!B2]	B	.S2	process_exception
+#endif
+ [B2]	B	.S2	system_call_saved
+ [!B2]	ADDAW	.D2	SP,2,B1
+ [!B2]	MV	.D1X	B1,A4
+	ADDKPC	.S2	ret_from_trap,B3,2
+
+ret_from_trap:
+	MV	.D2X	A4,B0
+ [!B0]	BNOP	.S2	ret_from_exception,5
+
+#ifdef CONFIG_C6X_BIG_KERNEL
+	MVKL	.S2	system_call_saved_noack,B3
+	MVKH	.S2	system_call_saved_noack,B3
+#endif
+	LDW	.D2T2	*+SP(REGS_B0+8),B0
+	LDW	.D2T1	*+SP(REGS_A4+8),A4
+	LDW	.D2T2	*+SP(REGS_B4+8),B4
+	LDW	.D2T1	*+SP(REGS_A6+8),A6
+	LDW	.D2T2	*+SP(REGS_B6+8),B6
+	LDW	.D2T1	*+SP(REGS_A8+8),A8
+#ifdef CONFIG_C6X_BIG_KERNEL
+ ||	B	.S2	B3
+#else
+ ||	B	.S2	system_call_saved_noack
+#endif
+	LDW	.D2T2	*+SP(REGS_B8+8),B8
+	NOP	4
+ENDPROC(_nmi_handler)
+
+	;;
+	;; Jump to schedule() then return to ret_from_isr
+	;;
+#ifdef	CONFIG_PREEMPT
+resume_kernel:
+	GET_THREAD_INFO A12
+	LDW	.D1T1	*+A12(THREAD_INFO_PREEMPT_COUNT),A1
+	NOP	4
+ [A1]	BNOP	.S2	restore_all,5
+
+preempt_schedule:
+	GET_THREAD_INFO A2
+	LDW	.D1T1	*+A2(THREAD_INFO_FLAGS),A1
+#ifdef CONFIG_C6X_BIG_KERNEL
+	MVKL	.S2	preempt_schedule_irq,B0
+	MVKH	.S2	preempt_schedule_irq,B0
+	NOP	2
+#else
+	NOP	4
+#endif
+	AND	.D1	_TIF_NEED_RESCHED,A1,A1
+ [!A1]	BNOP	.S2	restore_all,5
+#ifdef CONFIG_C6X_BIG_KERNEL
+	B	.S2	B0
+#else
+	B	.S2	preempt_schedule_irq
+#endif
+	ADDKPC	.S2	preempt_schedule,B3,4
+#endif /* CONFIG_PREEMPT */
+
+ENTRY(enable_exception)
+	DINT
+	MVC	.S2	TSR,B0
+	MVC	.S2	B3,NRP
+	MVK	.L2	0xc,B1
+	OR	.D2	B0,B1,B0
+	MVC	.S2	B0,TSR			;  Set GEE and XEN in TSR
+	B	.S2	NRP
+	NOP	5
+ENDPROC(enable_exception)
+
+ENTRY(sys_sigaltstack)
+#ifdef CONFIG_C6X_BIG_KERNEL
+	MVKL	.S1	do_sigaltstack,A0	; branch to do_sigaltstack
+	MVKH	.S1	do_sigaltstack,A0
+	B	.S2X	A0
+#else
+	B	.S2	do_sigaltstack
+#endif
+	LDW	.D2T1	*+SP(REGS_SP+8),A6
+	NOP	4
+ENDPROC(sys_sigaltstack)
+
+	;; kernel_execve
+ENTRY(kernel_execve)
+	MVK	.S2	__NR_execve,B0
+	SWE
+	BNOP	.S2	B3,5
+ENDPROC(kernel_execve)
+
+	;;
+	;; Special system calls
+	;; return address is in B3
+	;;
+ENTRY(sys_clone)
+	ADD	.D1X	SP,8,A4
+#ifdef CONFIG_C6X_BIG_KERNEL
+ ||	MVKL	.S1	sys_c6x_clone,A0
+	MVKH	.S1	sys_c6x_clone,A0
+	BNOP	.S2X	A0,5
+#else
+ ||	B	.S2	sys_c6x_clone
+	NOP	5
+#endif
+ENDPROC(sys_clone)
+
+ENTRY(sys_rt_sigreturn)
+	ADD	.D1X	SP,8,A4
+#ifdef CONFIG_C6X_BIG_KERNEL
+ ||	MVKL	.S1	do_rt_sigreturn,A0
+	MVKH	.S1	do_rt_sigreturn,A0
+	BNOP	.S2X	A0,5
+#else
+ ||	B	.S2	do_rt_sigreturn
+	NOP	5
+#endif
+ENDPROC(sys_rt_sigreturn)
+
+ENTRY(sys_execve)
+	ADDAW	.D2	SP,2,B6		; put regs addr in 4th parameter
+					; & adjust regs stack addr
+	LDW	.D2T2	*+SP(REGS_B4+8),B4
+
+	;; c6x_execve(char *name, char **argv,
+	;;            char **envp, struct pt_regs *regs)
+#ifdef CONFIG_C6X_BIG_KERNEL
+ ||	MVKL	.S1	sys_c6x_execve,A0
+	MVKH	.S1	sys_c6x_execve,A0
+	B	.S2X	A0
+#else
+ ||	B	.S2	sys_c6x_execve
+#endif
+	STW	.D2T2	B3,*SP--[2]
+	ADDKPC	.S2	ret_from_c6x_execve,B3,3
+
+ret_from_c6x_execve:
+	LDW	.D2T2	*++SP[2],B3
+	NOP	4
+	BNOP	.S2	B3,5
+ENDPROC(sys_execve)
+
+ENTRY(sys_pread_c6x)
+	MV	.D2X	A8,B7
+#ifdef CONFIG_C6X_BIG_KERNEL
+ ||	MVKL	.S1	sys_pread64,A0
+	MVKH	.S1	sys_pread64,A0
+	BNOP	.S2X	A0,5
+#else
+ ||	B	.S2	sys_pread64
+	NOP	5
+#endif
+ENDPROC(sys_pread_c6x)
+
+ENTRY(sys_pwrite_c6x)
+	MV	.D2X	A8,B7
+#ifdef CONFIG_C6X_BIG_KERNEL
+ ||	MVKL	.S1	sys_pwrite64,A0
+	MVKH	.S1	sys_pwrite64,A0
+	BNOP	.S2X	A0,5
+#else
+ ||	B	.S2	sys_pwrite64
+	NOP	5
+#endif
+ENDPROC(sys_pwrite_c6x)
+
+;; On Entry
+;;   A4 - path
+;;   B4 - offset_lo (LE), offset_hi (BE)
+;;   A6 - offset_lo (BE), offset_hi (LE)
+ENTRY(sys_truncate64_c6x)
+#ifdef CONFIG_CPU_BIG_ENDIAN
+	MV	.S2	B4,B5
+	MV	.D2X	A6,B4
+#else
+	MV	.D2X	A6,B5
+#endif
+#ifdef CONFIG_C6X_BIG_KERNEL
+ ||	MVKL	.S1	sys_truncate64,A0
+	MVKH	.S1	sys_truncate64,A0
+	BNOP	.S2X	A0,5
+#else
+ ||	B	.S2	sys_truncate64
+	NOP	5
+#endif
+ENDPROC(sys_truncate64_c6x)
+
+;; On Entry
+;;   A4 - fd
+;;   B4 - offset_lo (LE), offset_hi (BE)
+;;   A6 - offset_lo (BE), offset_hi (LE)
+ENTRY(sys_ftruncate64_c6x)
+#ifdef CONFIG_CPU_BIG_ENDIAN
+	MV	.S2	B4,B5
+	MV	.D2X	A6,B4
+#else
+	MV	.D2X	A6,B5
+#endif
+#ifdef CONFIG_C6X_BIG_KERNEL
+ ||	MVKL	.S1	sys_ftruncate64,A0
+	MVKH	.S1	sys_ftruncate64,A0
+	BNOP	.S2X	A0,5
+#else
+ ||	B	.S2	sys_ftruncate64
+	NOP	5
+#endif
+ENDPROC(sys_ftruncate64_c6x)
+
+#ifdef __ARCH_WANT_SYSCALL_OFF_T
+;; On Entry
+;;   A4 - fd
+;;   B4 - offset_lo (LE), offset_hi (BE)
+;;   A6 - offset_lo (BE), offset_hi (LE)
+;;   B6 - len
+;;   A8 - advice
+ENTRY(sys_fadvise64_c6x)
+#ifdef CONFIG_C6X_BIG_KERNEL
+	MVKL	.S1	sys_fadvise64,A0
+	MVKH	.S1	sys_fadvise64,A0
+	BNOP	.S2X	A0,2
+#else
+	B	.S2	sys_fadvise64
+	NOP	2
+#endif
+#ifdef CONFIG_CPU_BIG_ENDIAN
+	MV	.L2	B4,B5
+ ||	MV	.D2X	A6,B4
+#else
+	MV	.D2X	A6,B5
+#endif
+	MV	.D1X	B6,A6
+	MV	.D2X	A8,B6
+#endif
+ENDPROC(sys_fadvise64_c6x)
+
+;; On Entry
+;;   A4 - fd
+;;   B4 - offset_lo (LE), offset_hi (BE)
+;;   A6 - offset_lo (BE), offset_hi (LE)
+;;   B6 - len_lo (LE), len_hi (BE)
+;;   A8 - len_lo (BE), len_hi (LE)
+;;   B8 - advice
+ENTRY(sys_fadvise64_64_c6x)
+#ifdef CONFIG_C6X_BIG_KERNEL
+	MVKL	.S1	sys_fadvise64_64,A0
+	MVKH	.S1	sys_fadvise64_64,A0
+	BNOP	.S2X	A0,2
+#else
+	B	.S2	sys_fadvise64_64
+	NOP	2
+#endif
+#ifdef CONFIG_CPU_BIG_ENDIAN
+	MV	.L2	B4,B5
+ ||	MV	.D2X	A6,B4
+	MV	.L1	A8,A6
+ ||	MV	.D1X	B6,A7
+#else
+	MV	.D2X	A6,B5
+	MV	.L1	A8,A7
+ ||	MV	.D1X	B6,A6
+#endif
+	MV	.L2	B8,B6
+ENDPROC(sys_fadvise64_64_c6x)
+
+;; On Entry
+;;   A4 - fd
+;;   B4 - mode
+;;   A6 - offset_hi
+;;   B6 - offset_lo
+;;   A8 - len_hi
+;;   B8 - len_lo
+ENTRY(sys_fallocate_c6x)
+#ifdef CONFIG_C6X_BIG_KERNEL
+	MVKL	.S1	sys_fallocate,A0
+	MVKH	.S1	sys_fallocate,A0
+	BNOP	.S2X	A0,1
+#else
+	B	.S2	sys_fallocate
+	NOP
+#endif
+	MV	.D1	A6,A7
+	MV	.D1X	B6,A6
+	MV	.D2X	A8,B7
+	MV	.D2	B8,B6
+ENDPROC(sys_fallocate_c6x)
+
+	;; put this in .neardata for faster access when using DSBT mode
+	.section .neardata,"aw",@progbits
+	.global	current_ksp
+	.hidden	current_ksp
+current_ksp:
+	.word	init_thread_union + THREAD_START_SP