linux_dsm_epyc7002/arch/powerpc
Christophe Leroy 21f8b2fa3c powerpc/kprobes: Ignore traps that happened in real mode
When a program check exception happens while MMU translation is
disabled, following Oops happens in kprobe_handler() in the following
code:

	} else if (*addr != BREAKPOINT_INSTRUCTION) {

  BUG: Unable to handle kernel data access on read at 0x0000e268
  Faulting instruction address: 0xc000ec34
  Oops: Kernel access of bad area, sig: 11 [#1]
  BE PAGE_SIZE=16K PREEMPT CMPC885
  Modules linked in:
  CPU: 0 PID: 429 Comm: cat Not tainted 5.6.0-rc1-s3k-dev-00824-g84195dc6c58a #3267
  NIP:  c000ec34 LR: c000ecd8 CTR: c019cab8
  REGS: ca4d3b58 TRAP: 0300   Not tainted  (5.6.0-rc1-s3k-dev-00824-g84195dc6c58a)
  MSR:  00001032 <ME,IR,DR,RI>  CR: 2a4d3c52  XER: 00000000
  DAR: 0000e268 DSISR: c0000000
  GPR00: c000b09c ca4d3c10 c66d0620 00000000 ca4d3c60 00000000 00009032 00000000
  GPR08: 00020000 00000000 c087de44 c000afe0 c66d0ad0 100d3dd6 fffffff3 00000000
  GPR16: 00000000 00000041 00000000 ca4d3d70 00000000 00000000 0000416d 00000000
  GPR24: 00000004 c53b6128 00000000 0000e268 00000000 c07c0000 c07bb6fc ca4d3c60
  NIP [c000ec34] kprobe_handler+0x128/0x290
  LR [c000ecd8] kprobe_handler+0x1cc/0x290
  Call Trace:
  [ca4d3c30] [c000b09c] program_check_exception+0xbc/0x6fc
  [ca4d3c50] [c000e43c] ret_from_except_full+0x0/0x4
  --- interrupt: 700 at 0xe268
  Instruction dump:
  913e0008 81220000 38600001 3929ffff 91220000 80010024 bb410008 7c0803a6
  38210020 4e800020 38600000 4e800020 <813b0000> 6d2a7fe0 2f8a0008 419e0154
  ---[ end trace 5b9152d4cdadd06d ]---

kprobe is not prepared to handle events in real mode and functions
running in real mode should have been blacklisted, so kprobe_handler()
can safely bail out telling 'this trap is not mine' for any trap that
happened while in real-mode.

If the trap happened with MSR_IR or MSR_DR cleared, return 0
immediately.

Reported-by: Larry Finger <Larry.Finger@lwfinger.net>
Fixes: 6cc89bad60 ("powerpc/kprobes: Invoke handlers directly")
Cc: stable@vger.kernel.org # v4.10+
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Reviewed-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/424331e2006e7291a1bfe40e7f3fa58825f565e1.1582054578.git.christophe.leroy@c-s.fr
2020-03-25 12:09:51 +11:00
..
boot powerpc/Makefile: Mark phony targets as PHONY 2020-03-04 22:44:27 +11:00
configs virtio: fixes, cleanups 2020-02-07 12:26:34 -08:00
crypto crypto: remove CRYPTO_TFM_RES_BAD_KEY_LEN 2020-01-09 11:30:53 +08:00
include powerpc/eeh: Rework eeh_ops->probe() 2020-03-25 12:09:39 +11:00
kernel powerpc/kprobes: Ignore traps that happened in real mode 2020-03-25 12:09:51 +11:00
kexec powerpc: Avoid clang warnings around setjmp and longjmp 2019-11-25 21:45:43 +11:00
kvm powerpc/kvm: no need to check return value of debugfs_create functions 2020-03-04 22:44:25 +11:00
lib powerpc/sstep: Fix DS operand in ld encoding to appropriate value 2020-03-25 12:06:46 +11:00
math-emu treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
mm powerpc/32s: reorder Linux PTE bits to better match Hash PTE bits. 2020-03-25 12:09:27 +11:00
net treewide: Use sizeof_field() macro 2019-12-09 10:36:44 -08:00
oprofile powerpc updates for 5.6 2020-02-04 13:06:46 +00:00
perf powerpc/8xx: Use alternative scratch registers in DTLB miss handler 2020-01-27 22:36:16 +11:00
platforms powerpc/maple: Fix declaration made after definition 2020-03-25 12:09:48 +11:00
purgatory treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 441 2019-06-05 17:37:17 +02:00
sysdev powerpc updates for 5.6 2020-02-04 13:06:46 +00:00
tools powerpc: Do not consider weak unresolved symbol relocations as bad 2020-01-31 20:17:22 +11:00
xmon powerpc/xmon: Lower limits on nidump and ndump 2020-03-25 12:07:58 +11:00
Kbuild powerpc/kexec: Move kexec files into a dedicated subdir. 2019-11-21 15:41:34 +11:00
Kconfig powerpc updates for 5.6 2020-02-04 13:06:46 +00:00
Kconfig.debug powerpc/ptdump: Only enable PPC_CHECK_WX with STRICT_KERNEL_RWX 2020-01-23 21:31:13 +11:00
Makefile powerpc/Makefile: Mark phony targets as PHONY 2020-03-04 22:44:27 +11:00
Makefile.postlink powerpc: Do not consider weak unresolved symbol relocations as bad 2020-01-31 20:17:22 +11:00