@ 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
#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
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
projects / linux-2.6 / commitdiff