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 000000000000..ef01d77f2f65
--- /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