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- /*
- * 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
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