[v4,0/9] powerpc: Switch to CONFIG_THREAD_INFO_IN_TASK

The purpose of this serie is to activate CONFIG_THREAD_INFO_IN_TASK which
moves the thread_info into task_struct.

Moving thread_info into task_struct has the following advantages:
- It protects thread_info from corruption in the case of stack
overflows.
- Its address is harder to determine if stack addresses are
leaked, making a number of attacks more difficult.

Changes since RFC v3: (based on Nick's review)
 - Renamed task_size.h to task_size_user64.h to better relate to what it contains.
 - Handling of the isolation of thread_info cpu field inside CONFIG_SMP #ifdefs moved to a separate patch.
 - Removed CURRENT_THREAD_INFO macro completely.
 - Added a guard in asm/smp.h to avoid build failure before _TASK_CPU is defined.
 - Added a patch at the end to rename 'tp' pointers to 'sp' pointers
 - Renamed 'tp' into 'sp' pointers in preparation patch when relevant
 - Fixed a few commit logs
 - Fixed checkpatch report.

Changes since RFC v2:
 - Removed the modification of names in asm-offsets
 - Created a rule in arch/powerpc/Makefile to append the offset of current->cpu in CFLAGS
 - Modified asm/smp.h to use the offset set in CFLAGS
 - Squashed the renaming of THREAD_INFO to TASK_STACK in the preparation patch
 - Moved the modification of current_pt_regs in the patch activating CONFIG_THREAD_INFO_IN_TASK

Changes since RFC v1:
 - Removed the first patch which was modifying header inclusion order in timer
 - Modified some names in asm-offsets to avoid conflicts when including asm-offsets in C files
 - Modified asm/smp.h to avoid having to include linux/sched.h (using asm-offsets instead)
 - Moved some changes from the activation patch to the preparation patch.

Christophe Leroy (9):
  book3s/64: avoid circular header inclusion in mmu-hash.h
  powerpc: Only use task_struct 'cpu' field on SMP
  powerpc: Prepare for moving thread_info into task_struct
  powerpc: Activate CONFIG_THREAD_INFO_IN_TASK
  powerpc: regain entire stack space
  powerpc: 'current_set' is now a table of task_struct pointers
  powerpc/32: Remove CURRENT_THREAD_INFO and rename TI_CPU
  powerpc/64: Remove CURRENT_THREAD_INFO
  powerpc: clean stack pointers naming

 arch/powerpc/Kconfig                           |  1 +
 arch/powerpc/Makefile                          |  8 ++-
 arch/powerpc/include/asm/asm-prototypes.h      |  4 +-
 arch/powerpc/include/asm/book3s/64/mmu-hash.h  |  2 +-
 arch/powerpc/include/asm/exception-64s.h       |  4 +-
 arch/powerpc/include/asm/irq.h                 | 14 ++---
 arch/powerpc/include/asm/livepatch.h           |  2 +-
 arch/powerpc/include/asm/processor.h           | 39 +------------
 arch/powerpc/include/asm/ptrace.h              |  2 +-
 arch/powerpc/include/asm/reg.h                 |  2 +-
 arch/powerpc/include/asm/smp.h                 | 17 +++++-
 arch/powerpc/include/asm/task_size_user64.h    | 42 ++++++++++++++
 arch/powerpc/include/asm/thread_info.h         | 19 -------
 arch/powerpc/kernel/asm-offsets.c              | 10 ++--
 arch/powerpc/kernel/entry_32.S                 | 66 ++++++++--------------
 arch/powerpc/kernel/entry_64.S                 | 12 ++--
 arch/powerpc/kernel/epapr_hcalls.S             |  5 +-
 arch/powerpc/kernel/exceptions-64e.S           | 13 +----
 arch/powerpc/kernel/exceptions-64s.S           |  2 +-
 arch/powerpc/kernel/head_32.S                  | 14 ++---
 arch/powerpc/kernel/head_40x.S                 |  4 +-
 arch/powerpc/kernel/head_44x.S                 |  8 +--
 arch/powerpc/kernel/head_64.S                  |  1 +
 arch/powerpc/kernel/head_8xx.S                 |  2 +-
 arch/powerpc/kernel/head_booke.h               | 12 +---
 arch/powerpc/kernel/head_fsl_booke.S           | 16 +++---
 arch/powerpc/kernel/idle_6xx.S                 |  8 +--
 arch/powerpc/kernel/idle_book3e.S              |  2 +-
 arch/powerpc/kernel/idle_e500.S                |  8 +--
 arch/powerpc/kernel/idle_power4.S              |  2 +-
 arch/powerpc/kernel/irq.c                      | 77 +++++---------------------
 arch/powerpc/kernel/kgdb.c                     | 28 ----------
 arch/powerpc/kernel/machine_kexec_64.c         |  6 +-
 arch/powerpc/kernel/misc_32.S                  | 17 +++---
 arch/powerpc/kernel/process.c                  | 15 ++---
 arch/powerpc/kernel/setup-common.c             |  2 +-
 arch/powerpc/kernel/setup_32.c                 | 15 ++---
 arch/powerpc/kernel/setup_64.c                 | 41 ++++----------
 arch/powerpc/kernel/smp.c                      | 16 +++---
 arch/powerpc/kernel/trace/ftrace_64_mprofile.S |  6 +-
 arch/powerpc/kvm/book3s_hv_hmi.c               |  1 +
 arch/powerpc/mm/hash_low_32.S                  | 14 ++---
 arch/powerpc/sysdev/6xx-suspend.S              |  5 +-
 arch/powerpc/xmon/xmon.c                       |  2 +-
 44 files changed, 224 insertions(+), 362 deletions(-)
 create mode 100644 arch/powerpc/include/asm/task_size_user64.h

Christophe Leroy <christophe.leroy@c-s.fr> writes:

> The purpose of this serie is to activate CONFIG_THREAD_INFO_IN_TASK which
> moves the thread_info into task_struct.
>
> Moving thread_info into task_struct has the following advantages:
> - It protects thread_info from corruption in the case of stack
> overflows.
> - Its address is harder to determine if stack addresses are
> leaked, making a number of attacks more difficult.

We need to fixup bpf_jit32.h:

#ifdef CONFIG_SMP
#ifdef CONFIG_PPC64
#define PPC_BPF_LOAD_CPU(r)		\
	do { BUILD_BUG_ON(FIELD_SIZEOF(struct paca_struct, paca_index) != 2);	\
		PPC_LHZ_OFFS(r, 13, offsetof(struct paca_struct, paca_index));	\
	} while (0)
#else
#define PPC_BPF_LOAD_CPU(r)     \
	do { BUILD_BUG_ON(FIELD_SIZEOF(struct thread_info, cpu) != 4);		\
		PPC_LHZ_OFFS(r, (1 & ~(THREAD_SIZE - 1)),			\
				offsetof(struct thread_info, cpu));		\
	} while(0)
#endif
#else
#define PPC_BPF_LOAD_CPU(r) do { PPC_LI(r, 0); } while(0)
#endif


cheers