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| author | Dmitry Safonov <dima@arista.com> | 2020-06-09 06:30:07 +0200 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2020-06-09 18:39:10 +0200 |
| commit | 5489ab50c22771ddcad014968141b0d104d650a3 (patch) | |
| tree | da45382c2f04f70bf5f8abecb8132baf70f38874 /arch/arm/lib/backtrace.S | |
| parent | arc: add show_stack_loglvl() (diff) | |
| download | linux-5489ab50c22771ddcad014968141b0d104d650a3.tar.xz linux-5489ab50c22771ddcad014968141b0d104d650a3.zip | |
arm/asm: 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 argument 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: Russell King <linux@armlinux.org.uk>
Cc: Will Deacon <will@kernel.org>
Link: http://lkml.kernel.org/r/20200418201944.482088-5-dima@arista.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to '')
| -rw-r--r-- | arch/arm/lib/backtrace.S | 14 |
1 files changed, 10 insertions, 4 deletions
diff --git a/arch/arm/lib/backtrace.S b/arch/arm/lib/backtrace.S index 582925238d65..872f658638d9 100644 --- a/arch/arm/lib/backtrace.S +++ b/arch/arm/lib/backtrace.S @@ -18,6 +18,7 @@ #define sv_pc r6 #define mask r7 #define offset r8 +#define loglvl r9 ENTRY(c_backtrace) @@ -25,9 +26,10 @@ ENTRY(c_backtrace) ret lr ENDPROC(c_backtrace) #else - stmfd sp!, {r4 - r8, lr} @ Save an extra register so we have a location... + stmfd sp!, {r4 - r9, lr} @ Save an extra register so we have a location... movs frame, r0 @ if frame pointer is zero beq no_frame @ we have no stack frames + mov loglvl, r2 tst r1, #0x10 @ 26 or 32-bit mode? ARM( moveq mask, #0xfc000003 ) @@ -73,6 +75,7 @@ for_each_frame: tst frame, mask @ Check for address exceptions ldr r1, [frame, #-4] @ get saved lr mov r2, frame bic r1, r1, mask @ mask PC/LR for the mode + mov r3, loglvl bl dump_backtrace_entry ldr r1, [sv_pc, #-4] @ if stmfd sp!, {args} exists, @@ -80,12 +83,14 @@ for_each_frame: tst frame, mask @ Check for address exceptions teq r3, r1, lsr #11 ldreq r0, [frame, #-8] @ get sp subeq r0, r0, #4 @ point at the last arg + mov r2, loglvl bleq dump_backtrace_stm @ dump saved registers 1004: ldr r1, [sv_pc, #0] @ if stmfd sp!, {..., fp, ip, lr, pc} ldr r3, .Ldsi @ instruction exists, teq r3, r1, lsr #11 subeq r0, frame, #16 + mov r2, loglvl bleq dump_backtrace_stm @ dump saved registers teq sv_fp, #0 @ zero saved fp means @@ -96,9 +101,10 @@ for_each_frame: tst frame, mask @ Check for address exceptions bhi for_each_frame 1006: adr r0, .Lbad - mov r1, frame + mov r1, loglvl + mov r2, frame bl printk -no_frame: ldmfd sp!, {r4 - r8, pc} +no_frame: ldmfd sp!, {r4 - r9, pc} ENDPROC(c_backtrace) .pushsection __ex_table,"a" @@ -109,7 +115,7 @@ ENDPROC(c_backtrace) .long 1004b, 1006b .popsection -.Lbad: .asciz "Backtrace aborted due to bad frame pointer <%p>\n" +.Lbad: .asciz "%sBacktrace aborted due to bad frame pointer <%p>\n" .align .Ldsi: .word 0xe92dd800 >> 11 @ stmfd sp!, {... fp, ip, lr, pc} .word 0xe92d0000 >> 11 @ stmfd sp!, {} |