linux-kernel - [PATCH 3/4] ARM: backtrace-clang: give labels more descriptive names

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Message-Id: <20200730205112.2099429-4-ndesaulniers@google.com>
Date:   Thu, 30 Jul 2020 13:51:11 -0700
From:   Nick Desaulniers <ndesaulniers@...gle.com>
To:     Nathan Huckleberry <nhuck15@...il.com>,
        Russell King <linux@...linux.org.uk>
Cc:     Andrew Morton <akpm@...ux-foundation.org>,
        Chunyan Zhang <zhang.lyra@...il.com>,
        clang-built-linux@...glegroups.com,
        Dmitry Safonov <0x7f454c46@...il.com>,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        linux-mediatek@...ts.infradead.org,
        Lvqiang Huang <lvqiang.huang@...soc.com>,
        Matthias Brugger <matthias.bgg@...il.com>,
        Nick Desaulniers <ndesaulniers@...gle.com>,
        Miles Chen <miles.chen@...iatek.com>
Subject: [PATCH 3/4] ARM: backtrace-clang: give labels more descriptive names

Removes the 1004 label; it was neither a control flow target, nor an
instruction we expect to produce a fault.

Gives the labels slightly more readable names. The `b` suffixes are
handy to disambiguate between labels of the same identifier when there's
more than one. Since these labels are unique, let's just give them
names.

Signed-off-by: Nick Desaulniers <ndesaulniers@...gle.com>
---
 arch/arm/lib/backtrace-clang.S | 22 ++++++++++------------
 1 file changed, 10 insertions(+), 12 deletions(-)

diff --git a/arch/arm/lib/backtrace-clang.S b/arch/arm/lib/backtrace-clang.S
index 40eb2215eaf4..7dad2a6843a5 100644
--- a/arch/arm/lib/backtrace-clang.S
+++ b/arch/arm/lib/backtrace-clang.S
@@ -121,8 +121,8 @@ for_each_frame:	tst	frame, mask		@ Check for address exceptions
  * start. This value gets updated to be the function start later if it is
  * possible.
  */
-1001:		ldr	sv_pc, [frame, #4]	@ get saved 'pc'
-1002:		ldr	sv_fp, [frame, #0]	@ get saved fp
+load_pc:	ldr	sv_pc, [frame, #4]	@ get saved 'pc'
+load_fp:	ldr	sv_fp, [frame, #0]	@ get saved fp
 
 		teq	sv_fp, mask		@ make sure next frame exists
 		beq	no_frame
@@ -142,7 +142,7 @@ for_each_frame:	tst	frame, mask		@ Check for address exceptions
  * registers for the current function, but the stacktrace is still printed
  * properly.
  */
-1003:		ldr	sv_lr, [sv_fp, #4]	@ get saved lr from next frame
+load_lr:	ldr	sv_lr, [sv_fp, #4]	@ get saved lr from next frame
 
 		tst	sv_lr, #0		@ If there's no previous lr,
 		beq	finished_setup		@ we're done.
@@ -166,8 +166,7 @@ finished_setup:
 /*
  * Print the function (sv_pc) and where it was called from (sv_lr).
  */
-1004:		mov	r0, sv_pc
-
+		mov	r0, sv_pc
 		mov	r1, sv_lr
 		mov	r2, frame
 		bic	r1, r1, mask		@ mask PC/LR for the mode
@@ -182,7 +181,7 @@ finished_setup:
  * pointer the comparison will fail and no registers will print. Unwinding will
  * continue as if there had been no registers stored in this frame.
  */
-1005:		ldr	r1, [sv_pc, #0]		@ if stmfd sp!, {..., fp, lr}
+load_stmfd:	ldr	r1, [sv_pc, #0]		@ if stmfd sp!, {..., fp, lr}
 		ldr	r3, .Lopcode		@ instruction exists,
 		teq	r3, r1, lsr #11
 		ldr	r0, [frame]		@ locals are stored in
@@ -201,7 +200,7 @@ finished_setup:
 		mov	frame, sv_fp		@ above the current frame
 		bhi	for_each_frame
 
-1006:		adr	r0, .Lbad
+bad_frame:	adr	r0, .Lbad
 		mov	r1, loglvl
 		mov	r2, frame
 		bl	printk
@@ -216,11 +215,10 @@ bad_lr:		mov	sv_fp, #0
 ENDPROC(c_backtrace)
 		.pushsection __ex_table,"a"
 		.align	3
-		.long	1001b, 1006b
-		.long	1002b, 1006b
-		.long	1003b, 1006b
-		.long	1004b, 1006b
-		.long   1005b, 1006b
+		.long	load_pc, bad_frame
+		.long	load_fp, bad_frame
+		.long	load_lr, bad_frame
+		.long	load_stmfd, bad_frame
 		.long	prev_call, bad_lr
 		.popsection
 
-- 
2.28.0.163.g6104cc2f0b6-goog