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Message-Id: <20200418201944.482088-39-dima@arista.com>
Date: Sat, 18 Apr 2020 21:19:32 +0100
From: Dmitry Safonov <dima@...sta.com>
To: linux-kernel@...r.kernel.org
Cc: Dmitry Safonov <0x7f454c46@...il.com>,
Dmitry Safonov <dima@...sta.com>,
Andrew Morton <akpm@...ux-foundation.org>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Ingo Molnar <mingo@...nel.org>, Jiri Slaby <jslaby@...e.com>,
Petr Mladek <pmladek@...e.com>,
Sergey Senozhatsky <sergey.senozhatsky@...il.com>,
Steven Rostedt <rostedt@...dmis.org>,
Tetsuo Handa <penguin-kernel@...ove.SAKURA.ne.jp>,
Guan Xuetao <gxt@....edu.cn>
Subject: [PATCHv3 38/50] unicore32: Add loglvl to c_backtrace()
Currently, the log-level of show_stack() depends on a platform
realization. It creates situations where the headers are printed with
lower log level or higher than the stacktrace (depending on
a platform or user).
Furthermore, it forces the logic decision from user to an architecture
side. In result, some users as sysrq/kdb/etc are doing tricks with
temporary rising console_loglevel while printing their messages.
And in result it not only may print unwanted messages from other CPUs,
but also omit printing at all in the unlucky case where the printk()
was deferred.
Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems
an easier approach than introducing more printk buffers.
Also, it will consolidate printings with headers.
Add log level parameter to c_backtrace() as a preparation for
introducing show_stack_loglvl()
Cc: Guan Xuetao <gxt@....edu.cn>
[1]: https://lore.kernel.org/lkml/20190528002412.1625-1-dima@arista.com/T/#u
Signed-off-by: Dmitry Safonov <dima@...sta.com>
---
arch/unicore32/kernel/setup.h | 2 +-
arch/unicore32/kernel/traps.c | 2 +-
arch/unicore32/lib/backtrace.S | 24 ++++++++++++++++--------
3 files changed, 18 insertions(+), 10 deletions(-)
diff --git a/arch/unicore32/kernel/setup.h b/arch/unicore32/kernel/setup.h
index 03e70e37f472..967352323185 100644
--- a/arch/unicore32/kernel/setup.h
+++ b/arch/unicore32/kernel/setup.h
@@ -29,7 +29,7 @@ extern void kernel_thread_helper(void);
extern void __init early_signal_init(void);
extern asmlinkage void __backtrace(void);
-extern asmlinkage void c_backtrace(unsigned long fp);
+extern asmlinkage void c_backtrace(unsigned long fp, const char *loglvl);
extern void __show_regs(struct pt_regs *);
diff --git a/arch/unicore32/kernel/traps.c b/arch/unicore32/kernel/traps.c
index 3682a4c5d927..2b7d73456865 100644
--- a/arch/unicore32/kernel/traps.c
+++ b/arch/unicore32/kernel/traps.c
@@ -163,7 +163,7 @@ static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
printk("\n");
if (ok)
- c_backtrace(fp);
+ c_backtrace(fp, KERN_DEFAULT);
}
void show_stack(struct task_struct *tsk, unsigned long *sp)
diff --git a/arch/unicore32/lib/backtrace.S b/arch/unicore32/lib/backtrace.S
index f303671e2a4e..6221944b81f3 100644
--- a/arch/unicore32/lib/backtrace.S
+++ b/arch/unicore32/lib/backtrace.S
@@ -16,6 +16,7 @@
#define sv_fp v5
#define sv_pc v6
#define offset v8
+#define loglvl v9
ENTRY(__backtrace)
mov r0, fp
@@ -27,10 +28,11 @@ ENTRY(c_backtrace)
ENDPROC(__backtrace)
ENDPROC(c_backtrace)
#else
- stm.w (v4 - v8, lr), [sp-] @ Save an extra register
+ stm.w (v4 - v10, 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
+ mov loglvl, r1
1: stm.w (pc), [sp-] @ calculate offset of PC stored
ldw.w r0, [sp]+, #4 @ by stmfd for this CPU
@@ -95,9 +97,10 @@ for_each_frame:
bua for_each_frame
1006: adr r0, .Lbad
- mov r1, frame
+ mov r1, loglvl
+ mov r2, frame
b.l printk
-no_frame: ldm.w (v4 - v8, pc), [sp]+
+no_frame: ldm.w (v4 - v10, pc), [sp]+
ENDPROC(__backtrace)
ENDPROC(c_backtrace)
@@ -128,8 +131,11 @@ ENDPROC(c_backtrace)
add v7, v7, #1
cxor.a v7, #6
cmoveq v7, #1
- cmoveq r1, #'\n'
- cmovne r1, #' '
+ bne 201f
+ adr r0, .Lcr
+ mov r1, loglvl
+ b.l printk
+201:
ldw.w r3, [stack]+, #-4
mov r2, reg
csub.a r2, #8
@@ -141,18 +147,20 @@ ENDPROC(c_backtrace)
add r2, r2, #0x10 @ so r2 need add 16
201:
adr r0, .Lfp
+ mov r1, loglvl
b.l printk
2: sub.a reg, reg, #1
bns 1b
cxor.a v7, #0
beq 201f
adr r0, .Lcr
+ mov r1, loglvl
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"
+.Lfp: .asciz "%sr%d:%08x "
+.Lcr: .asciz "%s\n"
+.Lbad: .asciz "%sBacktrace 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, ()
--
2.26.0
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