diff options
Diffstat (limited to 'arch/arm/lib/backtrace.S')
| -rw-r--r-- | arch/arm/lib/backtrace.S | 165 |
1 files changed, 81 insertions, 84 deletions
diff --git a/arch/arm/lib/backtrace.S b/arch/arm/lib/backtrace.S index 74230083cbf4..84dc890d2bf3 100644 --- a/arch/arm/lib/backtrace.S +++ b/arch/arm/lib/backtrace.S @@ -17,8 +17,8 @@ @ fp is 0 or stack frame #define frame r4 -#define next r5 -#define save r6 +#define sv_fp r5 +#define sv_pc r6 #define mask r7 #define offset r8 @@ -31,108 +31,106 @@ ENTRY(c_backtrace) #if !defined(CONFIG_FRAME_POINTER) || !defined(CONFIG_PRINTK) mov pc, lr #else - stmfd sp!, {r4 - r8, lr} @ Save an extra register so we have a location... - tst r1, #0x10 @ 26 or 32-bit? - moveq mask, #0xfc000003 - movne mask, #0 - tst mask, r0 - movne r0, #0 - movs frame, r0 -1: moveq r0, #-2 - ldmeqfd sp!, {r4 - r8, pc} - -2: stmfd sp!, {pc} @ calculate offset of PC in STMIA instruction - ldr r0, [sp], #4 - adr r1, 2b - 4 + movs frame, r0 @ if frame pointer is zero + beq no_frame @ we have no stack frames + + tst r1, #0x10 @ 26 or 32-bit mode? + moveq mask, #0xfc000003 @ mask for 26-bit + movne mask, #0 @ mask for 32-bit + +1: stmfd sp!, {pc} @ calculate offset of PC stored + ldr r0, [sp], #4 @ by stmfd for this CPU + adr r1, 1b sub offset, r0, r1 -3: tst frame, mask @ Check for address exceptions... - bne 1b +/* + * 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 + * stmfd sp!, {r0 - r3} (optional) + * corrected pc => stmfd sp!, {..., fp, ip, lr, pc} + */ +for_each_frame: tst frame, mask @ Check for address exceptions + bne no_frame + +1001: ldr sv_pc, [frame, #0] @ get saved pc +1002: ldr sv_fp, [frame, #-12] @ get saved fp -1001: ldr next, [frame, #-12] @ get fp -1002: ldr r2, [frame, #-4] @ get lr -1003: ldr r3, [frame, #0] @ get pc - sub save, r3, offset @ Correct PC for prefetching - bic save, save, mask -1004: ldr r1, [save, #0] @ get instruction at function - mov r1, r1, lsr #10 - ldr r3, .Ldsi+4 - teq r1, r3 - subeq save, save, #4 - mov r0, save - bic r1, r2, mask + sub sv_pc, sv_pc, offset @ Correct PC for prefetching + bic sv_pc, sv_pc, mask @ mask PC/LR for the mode + +1003: ldr r2, [sv_pc, #-4] @ if stmfd sp!, {args} exists, + ldr r3, .Ldsi+4 @ adjust saved 'pc' back one + teq r3, r2, lsr #10 @ instruction + subne r0, sv_pc, #4 @ allow for mov + subeq r0, sv_pc, #8 @ allow for mov + stmia + + ldr r1, [frame, #-4] @ get saved lr + mov r2, frame + bic r1, r1, mask @ mask PC/LR for the mode bl dump_backtrace_entry - ldr r0, [frame, #-8] @ get sp - sub r0, r0, #4 -1005: ldr r1, [save, #4] @ get instruction at function+4 - mov r3, r1, lsr #10 - ldr r2, .Ldsi+4 - teq r3, r2 @ Check for stmia sp!, {args} - addeq save, save, #4 @ next instruction - bleq .Ldumpstm - - sub r0, frame, #16 -1006: ldr r1, [save, #4] @ Get 'stmia sp!, {rlist, fp, ip, lr, pc}' instruction - mov r3, r1, lsr #10 - ldr r2, .Ldsi - teq r3, r2 - bleq .Ldumpstm - - /* - * A zero next framepointer means we're done. - */ - teq next, #0 - ldmeqfd sp!, {r4 - r8, pc} - - /* - * The next framepointer must be above the - * current framepointer. - */ - cmp next, frame - mov frame, next - bhi 3b - b 1007f + ldr r1, [sv_pc, #-4] @ if stmfd sp!, {args} exists, + ldr r3, .Ldsi+4 + teq r3, r1, lsr #10 + ldreq r0, [frame, #-8] @ get sp + subeq r0, r0, #4 @ point at the last arg + bleq .Ldumpstm @ dump saved registers -/* - * Fixup for LDMDB. Note that this must not be in the fixup section. - */ -1007: ldr r0, =.Lbad +1004: ldr r1, [sv_pc, #0] @ if stmfd sp!, {..., fp, ip, lr, pc} + ldr r3, .Ldsi @ instruction exists, + teq r3, r1, lsr #10 + subeq r0, frame, #16 + bleq .Ldumpstm @ dump saved registers + + teq sv_fp, #0 @ zero saved fp means + beq no_frame @ no further frames + + cmp sv_fp, frame @ next frame must be + mov frame, sv_fp @ above the current frame + bhi for_each_frame + +1006: adr r0, .Lbad mov r1, frame bl printk - ldmfd sp!, {r4 - r8, pc} - .ltorg +no_frame: ldmfd sp!, {r4 - r8, pc} .section __ex_table,"a" .align 3 - .long 1001b, 1007b - .long 1002b, 1007b - .long 1003b, 1007b - .long 1004b, 1007b - .long 1005b, 1007b - .long 1006b, 1007b + .long 1001b, 1006b + .long 1002b, 1006b + .long 1003b, 1006b + .long 1004b, 1006b .previous #define instr r4 #define reg r5 #define stack r6 -.Ldumpstm: stmfd sp!, {instr, reg, stack, r7, r8, lr} +.Ldumpstm: stmfd sp!, {instr, reg, stack, r7, lr} mov stack, r0 mov instr, r1 - mov reg, #9 + mov reg, #10 mov r7, #0 1: mov r3, #1 tst instr, r3, lsl reg beq 2f add r7, r7, #1 - teq r7, #4 - moveq r7, #0 - moveq r3, #'\n' - movne r3, #' ' - ldr r2, [stack], #-4 - mov r1, reg + teq r7, #6 + moveq r7, #1 + moveq r1, #'\n' + movne r1, #' ' + ldr r3, [stack], #-4 + mov r2, reg adr r0, .Lfp bl printk 2: subs reg, reg, #1 @@ -140,14 +138,13 @@ ENTRY(c_backtrace) teq r7, #0 adrne r0, .Lcr blne printk - mov r0, stack - ldmfd sp!, {instr, reg, stack, r7, r8, pc} + ldmfd sp!, {instr, reg, stack, r7, pc} -.Lfp: .asciz " r%d = %08X%c" +.Lfp: .asciz "%cr%d:%08x" .Lcr: .asciz "\n" .Lbad: .asciz "Backtrace aborted due to bad frame pointer <%p>\n" .align -.Ldsi: .word 0x00e92dd8 >> 2 - .word 0x00e92d00 >> 2 +.Ldsi: .word 0xe92dd800 >> 10 @ stmfd sp!, {... fp, ip, lr, pc} + .word 0xe92d0000 >> 10 @ stmfd sp!, {} #endif |