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| author | Christophe Leroy <christophe.leroy@c-s.fr> | 2019-01-31 10:08:58 +0000 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2019-02-23 22:31:40 +1100 |
| commit | ed1cd6deb013a11959d17a94e35ce159197632da (patch) | |
| tree | fcfdc0de67e7753db653d06938d939fa0f0e924f /arch/powerpc/include/asm/thread_info.h | |
| parent | 7aef376679a428c6b7792fb4ce93364fd02caad4 (diff) | |
| download | linux-ed1cd6deb013a11959d17a94e35ce159197632da.tar.bz2 | |
powerpc: Activate CONFIG_THREAD_INFO_IN_TASK
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>
Diffstat (limited to 'arch/powerpc/include/asm/thread_info.h')
| -rw-r--r-- | arch/powerpc/include/asm/thread_info.h | 17 |
1 files changed, 2 insertions, 15 deletions
diff --git a/arch/powerpc/include/asm/thread_info.h b/arch/powerpc/include/asm/thread_info.h index 544cac0474cb..d91523c2c7d8 100644 --- a/arch/powerpc/include/asm/thread_info.h +++ b/arch/powerpc/include/asm/thread_info.h @@ -18,9 +18,9 @@ #define THREAD_SIZE (1 << THREAD_SHIFT) #ifdef CONFIG_PPC64 -#define CURRENT_THREAD_INFO(dest, sp) stringify_in_c(clrrdi dest, sp, THREAD_SHIFT) +#define CURRENT_THREAD_INFO(dest, sp) stringify_in_c(ld dest, PACACURRENT(r13)) #else -#define CURRENT_THREAD_INFO(dest, sp) stringify_in_c(rlwinm dest, sp, 0, 0, 31-THREAD_SHIFT) +#define CURRENT_THREAD_INFO(dest, sp) stringify_in_c(mr dest, r2) #endif #ifndef __ASSEMBLY__ @@ -34,8 +34,6 @@ * low level task data. */ struct thread_info { - struct task_struct *task; /* main task structure */ - int cpu; /* cpu we're on */ int preempt_count; /* 0 => preemptable, <0 => BUG */ unsigned long local_flags; /* private flags for thread */ @@ -58,8 +56,6 @@ struct thread_info { */ #define INIT_THREAD_INFO(tsk) \ { \ - .task = &tsk, \ - .cpu = 0, \ .preempt_count = INIT_PREEMPT_COUNT, \ .flags = 0, \ } @@ -67,15 +63,6 @@ struct thread_info { #define THREAD_SIZE_ORDER (THREAD_SHIFT - PAGE_SHIFT) /* how to get the thread information struct from C */ -static inline struct thread_info *current_thread_info(void) -{ - unsigned long val; - - asm (CURRENT_THREAD_INFO(%0,1) : "=r" (val)); - - return (struct thread_info *)val; -} - extern int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src); #ifdef CONFIG_PPC_BOOK3S_64 |