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powerpc: Activate CONFIG_THREAD_INFO_IN_TASK

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This patch activates 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.

This has the following consequences:
  - thread_info is now located at the beginning of task_struct.
  - The 'cpu' field is now in task_struct, and only exists when
    CONFIG_SMP is active.
  - thread_info doesn't have anymore the 'task' field.

This patch:
  - Removes all recopy of thread_info struct when the stack changes.
  - Changes the CURRENT_THREAD_INFO() macro to point to current.
  - Selects CONFIG_THREAD_INFO_IN_TASK.
  - Modifies raw_smp_processor_id() to get ->cpu from current without
    including linux/sched.h to avoid circular inclusion and without
    including asm/asm-offsets.h to avoid symbol names duplication
    between ASM constants and C constants.
  - Modifies klp_init_thread_info() to take a task_struct pointer
    argument.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
[mpe: Add task_stack.h to livepatch.h to fix build fails]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Christophe Leroy
2019-01-31 10:08:58 +00:00
committed by Michael Ellerman
parent 7aef376679
commit ed1cd6deb0
21 changed files with 56 additions and 194 deletions
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8
arch/powerpc/kernel/head_booke.h
View File

@@ -155,13 +155,7 @@ END_BTB_FLUSH_SECTION
stw r10,GPR11(r11); \
b 2f; \
/* COMING FROM PRIV MODE */ \
1: lwz r9,TI_FLAGS-EXC_LVL_FRAME_OVERHEAD(r11); \
lwz r10,TI_PREEMPT-EXC_LVL_FRAME_OVERHEAD(r11); \
stw r9,TI_FLAGS-EXC_LVL_FRAME_OVERHEAD(r8); \
stw r10,TI_PREEMPT-EXC_LVL_FRAME_OVERHEAD(r8); \
lwz r9,TI_TASK-EXC_LVL_FRAME_OVERHEAD(r11); \
stw r9,TI_TASK-EXC_LVL_FRAME_OVERHEAD(r8); \
mr r11,r8; \
1: mr r11, r8; \
2: mfspr r8,SPRN_SPRG_RSCRATCH_##exc_level; \
stw r12,GPR12(r11); /* save various registers */\
mflr r10; \