path: root/arch
diff options
authorDmitry Safonov <dima@arista.com>2020-06-08 21:31:51 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2020-06-09 09:39:12 -0700
commitde985dd50158fedde5f2916c1bcf949a0acf5cd0 (patch)
treeef2db42ff60f1cef37189a54fff6ddcbc3b58db6 /arch
parentee1e99009e914e4150774f5a717c179545c7699e (diff)
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() [1]: https://lore.kernel.org/lkml/20190528002412.1625-1-dima@arista.com/T/#u Signed-off-by: Dmitry Safonov <dima@arista.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Guan Xuetao <gxt@pku.edu.cn> Link: http://lkml.kernel.org/r/20200418201944.482088-39-dima@arista.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch')
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)
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
mov r0, fp
@@ -27,10 +28,11 @@ ENTRY(c_backtrace)
- 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]+
@@ -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
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
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"
.Ldsi: .word 0x92eec000 >> 14 @ stm.w sp, (... fp, ip, lr, pc)
.word 0x92e10000 >> 14 @ stm.w sp, ()