[Crash-utility] [PATCH] arm64: update mapping symbol filter in arm64_verify_symbol

Qianli Zhao zhaoqianligood at gmail.com
Thu Nov 26 04:49:36 UTC 2020


From: Qianli Zhao <zhaoqianli at xiaomi.com>

Name Meaning of mapping symbol:
$x
$x.<any...>
Start of a sequence of A64 instructions

$c
$c.<any...>
Start of a sequence of C64 instructions

$d
$d.<any...>
Start of a sequence of data items (for example, a literal pool)

Reference documents:
https://documentation-service.arm.com/static/5f9a92f6b1a7c5445f28fee6?token=

Signed-off-by: Qianli Zhao <zhaoqianli at xiaomi.com>
---
When use crash-arm64 parsing kdump,"dis" command can not completely parse out the disassembly code(aarch64-objdump is ok),miss some assembly code at the end,such as below:

The queued_spin_lock_slowpath() actual code segment of the function is from 0xffffffdf44b80d48 to ffffffecc41591d4,but "dis" command only dump from 0xffffffdf44b80d48 to 0xffffffdf44b80df0.

crash> dis queued_spin_lock_slowpath
0xffffffdf44b80d48 <$x.1>:      str     x30, [x18],#8
0xffffffdf44b80d4c <queued_spin_lock_slowpath+4>:       stp     x29, x30, [sp,#-64]!
....
0xffffffdf44b80dec <queued_spin_lock_slowpath+164>:     cbnz    w10, 0xffffffdf44b80e9c
0xffffffdf44b80df0 <queued_spin_lock_slowpath+168>:     nop 

The reason for the issue is that crash-tool thinks next vaild symbol is $x.3,but $x.* is a mapping symbol defined by ARM,this type of symbol needs skip.

ffffffdf44b80d48 (T) queued_spin_lock_slowpath
ffffffdf44b80df4 (t) $x.3
ffffffdf44b80dfc (t) $x.5
ffffffdf44b80e24 (t) $x.7
ffffffdf44b80e2c (t) $x.9
ffffffdf44b80f6c (t) $x.13
ffffffdf44b80f74 (t) $x.15
ffffffdf44b8102c (t) $x.19
ffffffdf44b81034 (t) $x.21
ffffffdf44b810e8 (t) $x.7
ffffffdf44b810e8 (T) rt_mutex_adjust_pi
ffffffdf44b8118c (t) $x.8

This issue will mislead us to analyze assembly issue:
[20332.505051] Call trace:
[20332.505057]  queued_spin_lock_slowpath+0x198/0x3a0---->//Beyond code segment?
[20332.505063]  do_raw_spin_lock+0x10c/0x12c
[20332.505071]  _raw_spin_lock_irqsave+0x3c/0x50
[20332.505080]  set_dspp_hist_irq_feature+0x180/0x1d4
[20332.505089]  sde_cp_crtc_setfeature+0x168/0x2f4
[20332.505095]  sde_cp_crtc_apply_properties+0x46c/0x76c
[20332.505102]  sde_crtc_atomic_begin+0x490/0x62c
[20332.505111]  drm_atomic_helper_commit_planes+0x5c/0x2bc
[20332.505117]  complete_commit+0xa0/0x264
[20332.505123]  _msm_drm_commit_work_cb+0x128/0x22c
[20332.505130]  kthread_worker_fn+0x110/0x1ac
[20332.505136]  kthread+0x160/0x170
[20332.505143]  ret_from_fork+0x10/0x18


Reference documents(page 7): 
https://documentation-service.arm.com/static/5f9a92f6b1a7c5445f28fee6?token=
---

 arm64.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/arm64.c b/arm64.c
index fdf77bd..24fd91e 100644
--- a/arm64.c
+++ b/arm64.c
@@ -510,9 +510,11 @@ arm64_verify_symbol(const char *name, ulong value, char type)
 	    ((type == 'a') || (type == 'n') || (type == 'N') || (type == 'U')))
 		return FALSE;
 
-	if (STREQ(name, "$d") || STREQ(name, "$x"))
+	if (STREQ(name, "$d") || STRNEQ(name, "$d.") ||
+		STREQ(name, "$x") || STRNEQ(name, "$x.") ||
+		STREQ(name, "$c") || STRNEQ(name, "$c."))
 		return FALSE;
-	
+
 	if ((type == 'A') && STRNEQ(name, "__crc_"))
 		return FALSE;
 
-- 
2.7.4




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