linux/arch/s390
Vasily Gorbik a994eddb94 s390/entry: save the caller of psw_idle
Currently psw_idle does not allocate a stack frame and does not
save its r14 and r15 into the save area. Even though this is valid from
call ABI point of view, because psw_idle does not make any calls
explicitly, in reality psw_idle is an entry point for controlled
transition into serving interrupts. So, in practice, psw_idle stack
frame is analyzed during stack unwinding. Depending on build options
that r14 slot in the save area of psw_idle might either contain a value
saved by previous sibling call or complete garbage.

  [task    0000038000003c28] do_ext_irq+0xd6/0x160
  [task    0000038000003c78] ext_int_handler+0xba/0xe8
  [task   *0000038000003dd8] psw_idle_exit+0x0/0x8 <-- pt_regs
 ([task    0000038000003dd8] 0x0)
  [task    0000038000003e10] default_idle_call+0x42/0x148
  [task    0000038000003e30] do_idle+0xce/0x160
  [task    0000038000003e70] cpu_startup_entry+0x36/0x40
  [task    0000038000003ea0] arch_call_rest_init+0x76/0x80

So, to make a stacktrace nicer and actually point for the real caller of
psw_idle in this frequently occurring case, make psw_idle save its r14.

  [task    0000038000003c28] do_ext_irq+0xd6/0x160
  [task    0000038000003c78] ext_int_handler+0xba/0xe8
  [task   *0000038000003dd8] psw_idle_exit+0x0/0x6 <-- pt_regs
 ([task    0000038000003dd8] arch_cpu_idle+0x3c/0xd0)
  [task    0000038000003e10] default_idle_call+0x42/0x148
  [task    0000038000003e30] do_idle+0xce/0x160
  [task    0000038000003e70] cpu_startup_entry+0x36/0x40
  [task    0000038000003ea0] arch_call_rest_init+0x76/0x80

Reviewed-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-04-12 12:44:31 +02:00
..
appldata s390/appldata: use struct_size() helper 2020-06-29 16:32:34 +02:00
boot s390: uv: Fix sysfs max number of VCPUs reporting 2021-01-27 13:00:04 +01:00
configs s390: remove IBM_PARTITION and CONFIGFS_FS from zfcpdump defconfig 2021-03-08 10:46:30 +01:00
crypto Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2021-02-21 17:23:56 -08:00
hypfs s390/hypfs: use store_tod_clock_ext() 2021-02-13 17:17:55 +01:00
include s390/unwind: add machine check handler stack 2021-04-05 11:30:07 +02:00
kernel s390/entry: save the caller of psw_idle 2021-04-12 12:44:31 +02:00
kvm s390/time,idle: get rid of unsigned long long 2021-03-08 10:46:27 +01:00
lib s390: convert to generic entry 2021-01-19 12:29:26 +01:00
mm s390 updates for the 5.12 merge window #2 2021-02-26 14:12:32 -08:00
net bpf: Rename BPF_XADD and prepare to encode other atomics in .imm 2021-01-14 18:34:29 -08:00
pci s390/pci: fix leak of PCI device structure 2021-03-15 19:10:56 +01:00
purgatory - Add support for the hugetlb_cma command line option to allocate gigantic 2020-12-14 16:22:26 -08:00
tools s390/opcodes: rename selhhhr to selfhr 2021-02-24 00:31:22 +01:00
Kbuild s390/numa: move code to arch/s390/kernel 2020-08-11 18:16:55 +02:00
Kconfig Rework of the X86 irq stack handling: 2021-02-24 16:32:23 -08:00
Kconfig.debug s390: convert to generic entry 2021-01-19 12:29:26 +01:00
Makefile arch: s390: Remove CONFIG_OPROFILE support 2021-01-29 10:05:51 +05:30