Skip to content

cloud-kernel
cloud-kernel

openanolis / cloud-kernel
接近 2 年 前同步成功

通知 170
Star 36
Fork 7
cloud-kernel
cloud-kernel
切换分支/标签
  1. 23 2月, 2017 1 次提交
  3. 20 2月, 2017 1 次提交
  5. 08 2月, 2017 1 次提交
    • M
      s390: add no-execute support · 57d7f939
      由 Martin Schwidefsky 提交于 
      Bit 0x100 of a page table, segment table of region table entry
can be used to disallow code execution for the virtual addresses
associated with the entry.

There is one tricky bit, the system call to return from a signal
is part of the signal frame written to the user stack. With a
non-executable stack this would stop working. To avoid breaking
things the protection fault handler checks the opcode that caused
the fault for 0x0a77 (sys_sigreturn) and 0x0aad (sys_rt_sigreturn)
and injects a system call. This is preferable to the alternative
solution with a stub function in the vdso because it works for
vdso=off and statically linked binaries as well.
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
      57d7f939
  7. 31 1月, 2017 1 次提交
    • M
      s390: store breaking event address only for program checks · 34525e1f
      由 Martin Schwidefsky 提交于 
      The principles of operations specifies that the breaking event address
is stored to the address 0x110 in the prefix page only for program checks.
The last branch in user space is lost as soon as a branch in kernel space
is executed after e.g. an svc. This makes it impossible to accurately
maintain the breaking event address for a user space process.

Simplify the code, just copy the current breaking event address from
0x110 to the task structure for program checks from user space.
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
      34525e1f
  9. 12 12月, 2016 1 次提交
  11. 07 12月, 2016 1 次提交
    • M
      s390: fix machine check panic stack switch · ce4dda3f
      由 Martin Schwidefsky 提交于 
      For system damage machine checks or machine checks due to invalid PSW
fields the system will be stopped. In order to get an oops message out
before killing the system the machine check handler branches to
.Lmcck_panic, switches to the panic stack and then does the usual
machine check handling.

The switch to the panic stack is incomplete, the stack pointer in %r15
is replaced, but the pt_regs pointer in %r11 is not. The result is
a program check which will kill the system in a slightly different way.
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
      ce4dda3f
  13. 25 11月, 2016 1 次提交
  15. 23 11月, 2016 1 次提交
  17. 15 11月, 2016 1 次提交
  19. 11 11月, 2016 2 次提交
  21. 08 8月, 2016 1 次提交
  23. 04 7月, 2016 1 次提交
    • H
      s390: have unique symbol for __switch_to address · 46210c44
      由 Heiko Carstens 提交于 
      After linking there are several symbols for the same address that the
__switch_to symbol points to. E.g.:

000000000089b9c0 T __kprobes_text_start
000000000089b9c0 T __lock_text_end
000000000089b9c0 T __lock_text_start
000000000089b9c0 T __sched_text_end
000000000089b9c0 T __switch_to

When disassembling with "objdump -d" this results in a missing
__switch_to function. It would be named __kprobes_text_start
instead. To unconfuse objdump add a nop in front of the kprobes text
section. That way __switch_to appears again.

Obviously this solution is sort of a hack, since it also depends on
link order if this works or not. However it is the best I can come up
with for now.
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
      46210c44
  25. 28 6月, 2016 1 次提交
  27. 10 3月, 2016 1 次提交
    • M
      s390: fix floating pointer register corruption (again) · e370e476
      由 Martin Schwidefsky 提交于 
      There is a tricky interaction between the machine check handler
and the critical sections of load_fpu_regs and save_fpu_regs
functions. If the machine check interrupts one of the two
functions the critical section cleanup will complete the function
before the machine check handler s390_do_machine_check is called.
Trouble is that the machine check handler needs to validate the
floating point registers *before* and not *after* the completion
of load_fpu_regs/save_fpu_regs.

The simplest solution is to rewind the PSW to the start of the
load_fpu_regs/save_fpu_regs and retry the function after the
return from the machine check handler.
Tested-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Cc: <stable@vger.kernel.org> # 4.3+
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
      e370e476
  29. 02 3月, 2016 1 次提交
  31. 27 11月, 2015 1 次提交
  33. 14 10月, 2015 5 次提交
  35. 30 9月, 2015 1 次提交
  37. 17 9月, 2015 1 次提交
  39. 03 8月, 2015 2 次提交
  41. 22 7月, 2015 5 次提交
    • M
      s390/nmi: use the normal asynchronous stack for machine checks · 2acb94f4
      由 Martin Schwidefsky 提交于 
      If a machine checks is received while the CPU is in the kernel, only
the s390_do_machine_check function will be called. The call to
s390_handle_mcck is postponed until the CPU returns to user space.
Because of this it is safe to use the asynchronous stack for machine
checks even if the CPU is already handling an interrupt.
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
      2acb94f4
    • M
      s390/kernel: squeeze a few more cycles out of the system call handler · a359bb11
      由 Martin Schwidefsky 提交于 
      Reorder the instructions of UPDATE_VTIME to improve superscalar execution,
remove duplicate checks for problem-state from the asynchronous interrupt
handlers, and move the check for problem-state from the synchronous
exit path to the program check path as it is only needed for program
checks inside the kernel.
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
      a359bb11
    • M
      s390/kvm: integrate HANDLE_SIE_INTERCEPT into cleanup_critical · d0fc4107
      由 Martin Schwidefsky 提交于 
      Currently there are two mechanisms to deal with cleanup work due to
interrupts. The HANDLE_SIE_INTERCEPT macro is used to undo the changes
required to enter SIE in sie64a. If the SIE instruction causes a program
check, or an asynchronous interrupt is received the HANDLE_SIE_INTERCEPT
code forwards the program execution to sie_exit.

All the other critical sections in entry.S are handled by the code in
cleanup_critical that is called by the SWITCH_ASYNC macro.

Move the sie64a function to the beginning of the critical section and
add the code from HANDLE_SIE_INTERCEPT to cleanup_critical. Add a special
case for the sie64a cleanup to the program check handler.
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
      d0fc4107
    • M
      s390/kvm: fix interrupt race with HANDLE_SIE_INTERCEPT · dcd2a9aa
      由 Martin Schwidefsky 提交于 
      The HANDLE_SIE_INTERCEPT macro is used in the interrupt handlers
and the program check handler to undo a few changes done by sie64a.
Among them are guest vs host LPP, the gmap ASCE vs kernel ASCE and
the bit that indicates that SIE is currently running on the CPU.

There is a race of a voluntary SIE exit vs asynchronous interrupts.
If the CPU completed the SIE instruction and the TM instruction of
the LPP macro at the time it receives an interrupt, the interrupt
handler will run while the LPP, the ASCE and the SIE bit are still
set up for guest execution. This might result in wrong sampling data,
but it will not cause data corruption or lockups.

The critical section in sie64a needs to be enlarged to include all
instructions that undo the changes required for guest execution.
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
      dcd2a9aa
    • H
      s390/kernel: lazy restore fpu registers · 9977e886
      由 Hendrik Brueckner 提交于 
      Improve the save and restore behavior of FPU register contents to use the
vector extension within the kernel.

The kernel does not use floating-point or vector registers and, therefore,
saving and restoring the FPU register contents are performed for handling
signals or switching processes only.  To prepare for using vector
instructions and vector registers within the kernel, enhance the save
behavior and implement a lazy restore at return to user space from a
system call or interrupt.

To implement the lazy restore, the save_fpu_regs() sets a CPU information
flag, CIF_FPU, to indicate that the FPU registers must be restored.
Saving and setting CIF_FPU is performed in an atomic fashion to be
interrupt-safe.  When the kernel wants to use the vector extension or
wants to change the FPU register state for a task during signal handling,
the save_fpu_regs() must be called first.  The CIF_FPU flag is also set at
process switch.  At return to user space, the FPU state is restored.  In
particular, the FPU state includes the floating-point or vector register
contents, as well as, vector-enablement and floating-point control.  The
FPU state restore and clearing CIF_FPU is also performed in an atomic
fashion.

For KVM, the restore of the FPU register state is performed when restoring
the general-purpose guest registers before the SIE instructions is started.
Because the path towards the SIE instruction is interruptible, the CIF_FPU
flag must be checked again right before going into SIE.  If set, the guest
registers must be reloaded again by re-entering the outer SIE loop.  This
is the same behavior as if the SIE critical section is interrupted.
Signed-off-by: NHendrik Brueckner <brueckner@linux.vnet.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
      9977e886
  43. 20 7月, 2015 1 次提交
  45. 08 5月, 2015 1 次提交
  47. 25 3月, 2015 2 次提交
  49. 08 12月, 2014 1 次提交
  51. 25 9月, 2014 1 次提交
  53. 20 5月, 2014 2 次提交
    • M
      s390: split TIF bits into CIF, PIF and TIF bits · d3a73acb
      由 Martin Schwidefsky 提交于 
      The oi and ni instructions used in entry[64].S to set and clear bits
in the thread-flags are not guaranteed to be atomic in regard to other
CPUs. Split the TIF bits into CPU, pt_regs and thread-info specific
bits. Updates on the TIF bits are done with atomic instructions,
updates on CPU and pt_regs bits are done with non-atomic instructions.
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
      d3a73acb
    • M
      s390/uaccess: simplify control register updates · beef560b
      由 Martin Schwidefsky 提交于 
      Always switch to the kernel ASCE in switch_mm. Load the secondary
space ASCE in finish_arch_post_lock_switch after checking that
any pending page table operations have completed. The primary
ASCE is loaded in entry[64].S. With this the update_primary_asce
call can be removed from the switch_to macro and from the start
of switch_mm function. Remove the load_primary argument from
update_user_asce/clear_user_asce, rename update_user_asce to
set_user_asce and rename update_primary_asce to load_kernel_asce.
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
      beef560b
  55. 22 4月, 2014 1 次提交