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Diffstat (limited to 'arch/unicore32/lib/backtrace.S')
| -rw-r--r-- | arch/unicore32/lib/backtrace.S | 163 |
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 000000000..ef01d77f2 --- /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 |