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f558b37bf4
linux/arch/powerpc/kernel
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Naveen N. Rao f558b37bf4 powerpc/optprobes: Fix TOC handling in optprobes trampoline 
Optprobes on powerpc are limited to kernel text area. We decided to also
optimize kretprobe_trampoline since that is also in kernel text area.
However,we failed to take into consideration the fact that the same
trampoline is also used to catch function returns from kernel modules.
As an example:

  $ sudo modprobe kobject-example
  $ sudo bash -c "echo 'r foo_show+8' > /sys/kernel/debug/tracing/kprobe_events"
  $ sudo bash -c "echo 1 > /sys/kernel/debug/tracing/events/kprobes/enable"
  $ sudo cat /sys/kernel/debug/kprobes/list
  c000000000041350  k  kretprobe_trampoline+0x0    [OPTIMIZED]
  d000000000e00200  r  foo_show+0x8  kobject_example
  $ cat /sys/kernel/kobject_example/foo
  Segmentation fault

With the below (trimmed) splat in dmesg:

  Unable to handle kernel paging request for data at address 0xfec40000
  Faulting instruction address: 0xc000000000041540
  Oops: Kernel access of bad area, sig: 11 [#1]
  ...
  NIP [c000000000041540] optimized_callback+0x70/0xe0
  LR [c000000000041e60] optinsn_slot+0xf8/0x10000
  Call Trace:
  [c0000000c7327850] [c000000000289af4] alloc_set_pte+0x1c4/0x860 (unreliable)
  [c0000000c7327890] [c000000000041e60] optinsn_slot+0xf8/0x10000
  --- interrupt: 700 at 0xc0000000c7327a80
	       LR = kretprobe_trampoline+0x0/0x10
  [c0000000c7327ba0] [c0000000003a30d4] sysfs_kf_seq_show+0x104/0x1d0
  [c0000000c7327bf0] [c0000000003a0bb4] kernfs_seq_show+0x44/0x60
  [c0000000c7327c10] [c000000000330578] seq_read+0xf8/0x560
  [c0000000c7327cb0] [c0000000003a1e64] kernfs_fop_read+0x194/0x260
  [c0000000c7327d00] [c0000000002f9954] __vfs_read+0x44/0x1a0
  [c0000000c7327d90] [c0000000002fb4cc] vfs_read+0xbc/0x1b0
  [c0000000c7327de0] [c0000000002fd138] SyS_read+0x68/0x110
  [c0000000c7327e30] [c00000000000b8e0] system_call+0x38/0xfc

Fix this by loading up the kernel TOC before calling into the kernel.
The original TOC gets restored as part of the usual pt_regs restore.

Fixes: 762df10bad ("powerpc/kprobes: Optimize kprobe in kretprobe_trampoline()")
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-02-23 08:23:30 +11:00
..
vdso32 powerpc/vdso: Fix build rules to rebuild vdsos correctly 2016-08-10 23:04:12 +10:00
vdso64 powerpc/vdso64: Use double word compare on pointers 2016-09-29 15:17:57 +10:00
.gitignore
align.c powerpc/64: Clean up ppc64_caches using a struct per cache 2017-02-06 19:46:04 +11:00
asm-offsets.c powerpc/asm: Define STACK_PT_REGS_OFFSET macro in asm-offsets.c 2017-02-15 21:47:51 +11:00
audit.c
btext.c powerpc/mm: Use a helper for finding pte bits mapping I/O area 2016-05-01 18:32:32 +10:00
cacheinfo.c
cacheinfo.h
compat_audit.c
cpu_setup_6xx.S powerpc: Various typo fixes 2016-06-14 13:58:26 +10:00
cpu_setup_44x.S
cpu_setup_fsl_booke.S powerpc/cache: add cache flush operation for various e500 2016-03-04 23:44:51 -06:00
cpu_setup_pa6t.S
cpu_setup_power.S powerpc updates for 4.10 2016-12-16 09:26:42 -08:00
cpu_setup_ppc970.S
cputable.c powerpc: Add POWER9 architected mode to cputable 2017-02-17 21:48:56 +11:00
crash_dump.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
crash.c powerpc/crash: Rearrange loop condition to avoid out of bounds array access 2016-07-14 20:26:22 +10:00
dbell.c
dma-iommu.c dma-mapping: use unsigned long for dma_attrs 2016-08-04 08:50:07 -04:00
dma-swiotlb.c
dma.c arch/powerpc: add option to skip DMA sync as a part of mapping 2016-12-14 16:04:07 -08:00
eeh_cache.c powerpc/eeh: Fix pr_debug()s in eeh_cache.c 2016-07-08 22:09:50 +10:00
eeh_dev.c powerpc/pci: Delay populating pdn 2016-06-21 15:30:56 +10:00
eeh_driver.c powerpc updates for 4.10 2016-12-16 09:26:42 -08:00
eeh_event.c powerpc/pci: Always print PHB and PE numbers as hexadecimal 2016-11-22 11:57:07 +11:00
eeh_pe.c powerpc/pci: Always print PHB and PE numbers as hexadecimal 2016-11-22 11:57:07 +11:00
eeh_sysfs.c
eeh.c powerpc/eeh: Enable IO path on permanent error 2017-01-18 15:11:19 +11:00
entry_32.S powerpc/8xx: Perf events on PPC 8xx 2017-01-26 17:49:34 -06:00
entry_64.S Merge branch 'kbuild' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild 2016-10-14 14:26:58 -07:00
epapr_hcalls.S ppc: move exports to definitions 2016-08-07 23:50:09 -04:00
epapr_paravirt.c
exceptions-64e.S powerpc/64e: Don't branch to dot symbols 2016-11-28 22:32:30 +11:00
exceptions-64s.S Merge branch 'topic/ppc-kvm' into next 2017-02-14 17:18:29 +11:00
fadump.c powerpc/fadump: Fix the race in crash_fadump(). 2017-01-30 16:35:16 +11:00
firmware.c
fpu.S Merge branch 'kbuild' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild 2016-10-14 14:26:58 -07:00
fsl_booke_entry_mapping.S
ftrace.c powerpc/ftrace: Fix the comments for ftrace_modify_code 2016-12-03 22:10:15 +11:00
head_8xx.S powerpc/8xx: Perf events on PPC 8xx 2017-01-26 17:49:34 -06:00
head_32.S powerpc/32: Remove FIX_SRR1 2017-01-26 17:49:32 -06:00
head_40x.S ppc: move exports to definitions 2016-08-07 23:50:09 -04:00
head_44x.S ppc: move exports to definitions 2016-08-07 23:50:09 -04:00
head_64.S powerpc: Change places using CONFIG_KEXEC to use CONFIG_KEXEC_CORE instead. 2016-11-30 23:15:11 +11:00
head_booke.h
head_fsl_booke.S ppc: move exports to definitions 2016-08-07 23:50:09 -04:00
hw_breakpoint.c Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/scottwood/linux into next 2017-02-18 21:37:14 +11:00
idle_6xx.S
idle_book3e.S
idle_book3s.S Merge branch 'topic/ppc-kvm' into next 2017-02-14 17:18:29 +11:00
idle_e500.S
idle_power4.S
idle.c
ima_kexec.c powerpc: ima: send the kexec buffer to the next kernel 2016-12-20 09:48:44 -08:00
io-workarounds.c
io.c
iomap.c powerpc: Move isa bridge definitions to separate include 2017-01-31 13:54:17 +11:00
iommu.c powerpc: implement the DMA_ATTR_NO_WARN attribute 2016-10-11 15:06:32 -07:00
irq.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
isa-bridge.c powerpc: Add support for non-PCI ISA bridges 2017-01-31 13:54:17 +11:00
jump_label.c
kexec_elf_64.c powerpc: ima: send the kexec buffer to the next kernel 2016-12-20 09:48:44 -08:00
kgdb.c powerpc: Fix kgdb on little endian ppc64le 2016-02-18 00:03:26 +11:00
kprobes.c powerpc/kprobes: Remove kprobe_exceptions_notify() 2017-02-10 14:43:15 +11:00
kvm_emul.S
kvm.c
l2cr_6xx.S
legacy_serial.c powerpc/powernv: Add support for direct mapped LPC on POWER9 2017-01-31 13:54:18 +11:00
machine_kexec_32.c
machine_kexec_64.c powerpc: Add purgatory for kexec_file_load() implementation. 2016-11-30 23:15:26 +11:00
machine_kexec_file_64.c powerpc: ima: send the kexec buffer to the next kernel 2016-12-20 09:48:44 -08:00
machine_kexec.c powerpc: Update of_remove_property() call sites to remove null checking 2016-05-11 21:54:04 +10:00
Makefile powerpc/kprobes: Implement Optprobes 2017-02-10 13:28:04 +11:00
mce_power.c powerpc/mm/radix: Fix CONFIG_PPC_MMU_STD_64 typo 2016-05-11 21:53:59 +10:00
mce.c powerpc/mce: Remove unused but set variable 2016-11-18 22:40:38 +11:00
misc_32.S powerpc: Fix build warning on 32-bit PPC 2016-12-25 16:12:20 -08:00
misc_64.S powerpc/64: Fix naming of cache block vs. cache line 2017-02-06 19:46:04 +11:00
misc.S ppc: move exports to definitions 2016-08-07 23:50:09 -04:00
module_32.c powerpc/module: Only try to generate the ftrace_caller() stub once 2016-03-07 14:53:53 +11:00
module_64.c powerpc/module: Add support for R_PPC64_REL32 relocations 2016-11-14 11:11:51 +11:00
module.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
msi.c
nvram_64.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
of_platform.c powerpc/of_platform: Use builtin_platform_driver 2016-11-25 14:07:51 +11:00
optprobes_head.S powerpc/optprobes: Fix TOC handling in optprobes trampoline 2017-02-23 08:23:30 +11:00
optprobes.c powerpc/kprobes: Optimize kprobe in kretprobe_trampoline() 2017-02-10 13:28:05 +11:00
paca.c powerpc/mm: Convert early cpu/mmu feature check to use the new helpers 2016-08-01 11:15:01 +10:00
pci_32.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
pci_64.c powerpc fixes for 4.7 #5 2016-07-15 14:57:47 +10:00
pci_dn.c powerpc/pci: Fix build with PCI_IOV=y and EEH=n 2016-07-07 16:33:27 +10:00
pci_of_scan.c powerpc: Remove all usages of NO_IRQ 2016-09-20 20:57:12 +10:00
pci-common.c powerpc/kernel: Remove error message in pcibios_setup_phb_resources() 2017-02-17 22:18:21 +11:00
pci-hotplug.c powerpc/pci: Don't scan empty slot 2016-05-11 21:54:26 +10:00
pmc.c
ppc32.h
ppc_save_regs.S
proc_powerpc.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
process.c powerpc/8xx: Implement hw_breakpoint 2017-01-25 02:43:59 -06:00
prom_init_check.sh
prom_init.c powerpc/pseries: Advertise Hot Plug Event support to firmware 2017-02-21 21:32:53 +11:00
prom_parse.c
prom.c powerpc: Change places using CONFIG_KEXEC to use CONFIG_KEXEC_CORE instead. 2016-11-30 23:15:11 +11:00
ptrace32.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
ptrace.c powerpc/ptrace: Preserve previous TM fprs/vsrs on short regset write 2017-01-20 14:55:19 +11:00
reloc_32.S
reloc_64.S
rtas_flash.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
rtas_pci.c
rtas-proc.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
rtas-rtc.c
rtas.c powerpc/kernel: Fix unbalanced refcount on RTAS device node 2017-01-25 13:34:21 +11:00
rtasd.c powerpc/pseries: Update affinity for memory and cpus specified in a PRRN event 2017-02-02 20:36:38 +11:00
setup_32.c powerpc: Move {d,i,u}cache_bsize definitions to a common place 2017-02-06 19:46:04 +11:00
setup_64.c powerpc/64e: Fix bogus usage of WARN_ONCE() 2017-02-15 20:24:25 +11:00
setup-common.c powerpc: Move {d,i,u}cache_bsize definitions to a common place 2017-02-06 19:46:04 +11:00
setup.h powerpc: Merge 32-bit and 64-bit setup_arch() 2016-07-21 19:17:46 +10:00
signal_32.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
signal_64.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
signal.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
signal.h powerpc: tm: Rename transct_(*) to ck(\1)_state 2016-10-04 20:33:16 +11:00
smp-tbsync.c
smp.c powerpc: Change places using CONFIG_KEXEC to use CONFIG_KEXEC_CORE instead. 2016-11-30 23:15:11 +11:00
stacktrace.c powerpc: Implement save_stack_trace_regs() to enable kprobe stack tracing 2016-01-11 14:27:28 +11:00
suspend.c
swsusp_32.S
swsusp_64.c
swsusp_asm64.S
swsusp_booke.S
swsusp.c powerpc/mm: Abstraction for switch_mmu_context() 2016-05-01 18:33:04 +10:00
sys_ppc32.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
syscalls.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
sysfs.c powerpc/sysfs: Convert to hotplug state machine 2016-11-22 23:34:42 +01:00
systbl_chk.c powerpc: Standardise on NR_syscalls rather than __NR_syscalls. 2015-11-26 22:11:17 +11:00
systbl_chk.sh powerpc: Standardise on NR_syscalls rather than __NR_syscalls. 2015-11-26 22:11:17 +11:00
systbl.S
tau_6xx.c
time.c clocksource: Use a plain u64 instead of cycle_t 2016-12-25 11:04:12 +01:00
tm.S powerpc: tm: Rename transct_(*) to ck(\1)_state 2016-10-04 20:33:16 +11:00
trace_clock.c
traps.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
udbg_16550.c
udbg.c
uprobes.c
vdso.c powerpc/64: Clean up ppc64_caches using a struct per cache 2017-02-06 19:46:04 +11:00
vecemu.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
vector.S Merge branch 'kbuild' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild 2016-10-14 14:26:58 -07:00
vmlinux.lds.S powerpc/64: Fix placement of .text to be immediately following .head.text 2016-12-01 22:26:31 +11:00