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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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4
arch/powerpc/include/asm/irq.h
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@@ -51,9 +51,6 @@ struct pt_regs;
extern struct thread_info *critirq_ctx[NR_CPUS];
extern struct thread_info *dbgirq_ctx[NR_CPUS];
extern struct thread_info *mcheckirq_ctx[NR_CPUS];
extern void exc_lvl_ctx_init(void);
#else
#define exc_lvl_ctx_init()
#endif
/*
@@ -62,7 +59,6 @@ extern void exc_lvl_ctx_init(void);
extern struct thread_info *hardirq_ctx[NR_CPUS];
extern struct thread_info *softirq_ctx[NR_CPUS];
extern void irq_ctx_init(void);
void call_do_softirq(void *sp);
void call_do_irq(struct pt_regs *regs, void *sp);
extern void do_IRQ(struct pt_regs *regs);