unicore32 core architecture: process/thread related codes

This patch implements process/thread related codes. Backtrace and stacktrace are here.

Signed-off-by: Guan Xuetao <gxt@mprc.pku.edu.cn>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>

1 files changed, 163 insertions, 0 deletions

diff --git a/arch/unicore32/lib/backtrace.S b/arch/unicore32/lib/backtrace.S
new file mode 100644
index 0000000000000..ef01d77f2f659
--- /dev/null
+++ b/arch/unicore32/lib/backtrace.S
@@ -0,0 +1,163 @@
+/*
+ * linux/arch/unicore32/lib/backtrace.S
+ *
+ * Code specific to PKUnity SoC and UniCore ISA
+ *
+ * Copyright (C) 2001-2010 GUAN Xue-tao
+ *
+ * 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/linkage.h>
+#include <asm/assembler.h>
+		.text
+
+@ fp is 0 or stack frame
+
+#define frame	v4
+#define sv_fp	v5
+#define sv_pc	v6
+#define offset	v8
+
+ENTRY(__backtrace)
+		mov	r0, fp
+
+ENTRY(c_backtrace)
+
+#if !defined(CONFIG_FRAME_POINTER) || !defined(CONFIG_PRINTK)
+		mov	pc, lr
+ENDPROC(__backtrace)
+ENDPROC(c_backtrace)
+#else
+		stm.w	(v4 - v8, lr), [sp-]	@ Save an extra register
+						@ so we have a location...
+		mov.a	frame, r0		@ if frame pointer is zero
+		beq	no_frame		@ we have no stack frames
+
+1:		stm.w	(pc), [sp-]		@ calculate offset of PC stored
+		ldw.w	r0, [sp]+, #4		@ by stmfd for this CPU
+		adr	r1, 1b
+		sub	offset, r0, r1
+
+/*
+ * Stack frame layout:
+ *             optionally saved caller registers (r4 - r10)
+ *             saved fp
+ *             saved sp
+ *             saved lr
+ *    frame => saved pc
+ *             optionally saved arguments (r0 - r3)
+ * saved sp => <next word>
+ *
+ * Functions start with the following code sequence:
+ *                  mov   ip, sp
+ *                  stm.w (r0 - r3), [sp-] (optional)
+ * corrected pc =>  stm.w sp, (..., fp, ip, lr, pc)
+ */
+for_each_frame:
+
+1001:		ldw	sv_pc, [frame+], #0	@ get saved pc
+1002:		ldw	sv_fp, [frame+], #-12	@ get saved fp
+
+		sub	sv_pc, sv_pc, offset	@ Correct PC for prefetching
+
+1003:		ldw	r2, [sv_pc+], #-4	@ if stmfd sp, {args} exists,
+		ldw	r3, .Ldsi+4		@ adjust saved 'pc' back one
+		cxor.a	r3, r2 >> #14		@ instruction
+		beq	201f
+		sub	r0, sv_pc, #4		@ allow for mov
+		b	202f
+201:
+		sub	r0, sv_pc, #8		@ allow for mov + stmia
+202:
+		ldw	r1, [frame+], #-4	@ get saved lr
+		mov	r2, frame
+		b.l	dump_backtrace_entry
+
+		ldw	r1, [sv_pc+], #-4	@ if stmfd sp, {args} exists,
+		ldw	r3, .Ldsi+4
+		cxor.a	r3, r1 >> #14
+		bne	1004f
+		ldw	r0, [frame+], #-8	@ get sp
+		sub	r0, r0, #4		@ point at the last arg
+		b.l	.Ldumpstm		@ dump saved registers
+
+1004:		ldw	r1, [sv_pc+], #0	@ if stmfd {, fp, ip, lr, pc}
+		ldw	r3, .Ldsi		@ instruction exists,
+		cxor.a	r3, r1 >> #14
+		bne	201f
+		sub	r0, frame, #16
+		b.l	.Ldumpstm		@ dump saved registers
+201:
+		cxor.a	sv_fp, #0		@ zero saved fp means
+		beq	no_frame		@ no further frames
+
+		csub.a	sv_fp, frame		@ next frame must be
+		mov	frame, sv_fp		@ above the current frame
+		bua	for_each_frame
+
+1006:		adr	r0, .Lbad
+		mov	r1, frame
+		b.l	printk
+no_frame:	ldm.w	(v4 - v8, pc), [sp]+
+ENDPROC(__backtrace)
+ENDPROC(c_backtrace)
+
+		.pushsection __ex_table,"a"
+		.align	3
+		.long	1001b, 1006b
+		.long	1002b, 1006b
+		.long	1003b, 1006b
+		.long	1004b, 1006b
+		.popsection
+
+#define instr v4
+#define reg   v5
+#define stack v6
+
+.Ldumpstm:	stm.w	(instr, reg, stack, v7, lr), [sp-]
+		mov	stack, r0
+		mov	instr, r1
+		mov	reg, #14
+		mov	v7, #0
+1:		mov	r3, #1
+		csub.a	reg, #8
+		bne	201f
+		sub	reg, reg, #3
+201:
+		cand.a	instr, r3 << reg
+		beq	2f
+		add	v7, v7, #1
+		cxor.a	v7, #6
+		cmoveq	v7, #1
+		cmoveq	r1, #'\n'
+		cmovne	r1, #' '
+		ldw.w	r3, [stack]+, #-4
+		mov	r2, reg
+		csub.a	r2, #8
+		bsl	201f
+		sub	r2, r2, #3
+201:
+		cand.a	instr, #0x40		@ if H is 1, high 16 regs
+		beq	201f
+		add	r2, r2, #0x10		@ so r2 need add 16
+201:
+		adr	r0, .Lfp
+		b.l	printk
+2:		sub.a	reg, reg, #1
+		bns	1b
+		cxor.a	v7, #0
+		beq	201f
+		adr	r0, .Lcr
+		b.l	printk
+201:		ldm.w	(instr, reg, stack, v7, pc), [sp]+
+
+.Lfp:		.asciz	"%cr%d:%08x"
+.Lcr:		.asciz	"\n"
+.Lbad:		.asciz	"Backtrace aborted due to bad frame pointer <%p>\n"
+		.align
+.Ldsi:		.word	0x92eec000 >> 14	@ stm.w sp, (... fp, ip, lr, pc)
+		.word	0x92e10000 >> 14	@ stm.w sp, ()
+
+#endif