diff options
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 | |
parent | 7aef376679a428c6b7792fb4ce93364fd02caad4 (diff) | |
download | linux-ed1cd6deb013a11959d17a94e35ce159197632da.tar.gz linux-ed1cd6deb013a11959d17a94e35ce159197632da.tar.bz2 linux-ed1cd6deb013a11959d17a94e35ce159197632da.zip |
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')
-rw-r--r-- | arch/powerpc/include/asm/irq.h | 4 | ||||
-rw-r--r-- | arch/powerpc/include/asm/livepatch.h | 7 | ||||
-rw-r--r-- | arch/powerpc/include/asm/smp.h | 17 | ||||
-rw-r--r-- | arch/powerpc/include/asm/thread_info.h | 17 |
4 files changed, 22 insertions, 23 deletions
diff --git a/arch/powerpc/include/asm/irq.h b/arch/powerpc/include/asm/irq.h index 2efbae8d93be..28a7ace0a1b9 100644 --- a/arch/powerpc/include/asm/irq.h +++ b/arch/powerpc/include/asm/irq.h @@ -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); diff --git a/arch/powerpc/include/asm/livepatch.h b/arch/powerpc/include/asm/livepatch.h index 47a03b9b528b..5070df19d463 100644 --- a/arch/powerpc/include/asm/livepatch.h +++ b/arch/powerpc/include/asm/livepatch.h @@ -21,6 +21,7 @@ #include <linux/module.h> #include <linux/ftrace.h> +#include <linux/sched/task_stack.h> #ifdef CONFIG_LIVEPATCH static inline int klp_check_compiler_support(void) @@ -43,13 +44,13 @@ static inline unsigned long klp_get_ftrace_location(unsigned long faddr) return ftrace_location_range(faddr, faddr + 16); } -static inline void klp_init_thread_info(struct thread_info *ti) +static inline void klp_init_thread_info(struct task_struct *p) { /* + 1 to account for STACK_END_MAGIC */ - ti->livepatch_sp = (unsigned long *)(ti + 1) + 1; + task_thread_info(p)->livepatch_sp = end_of_stack(p) + 1; } #else -static void klp_init_thread_info(struct thread_info *ti) { } +static inline void klp_init_thread_info(struct task_struct *p) { } #endif /* CONFIG_LIVEPATCH */ #endif /* _ASM_POWERPC_LIVEPATCH_H */ diff --git a/arch/powerpc/include/asm/smp.h b/arch/powerpc/include/asm/smp.h index 41695745032c..0de717e16dd6 100644 --- a/arch/powerpc/include/asm/smp.h +++ b/arch/powerpc/include/asm/smp.h @@ -83,7 +83,22 @@ int is_cpu_dead(unsigned int cpu); /* 32-bit */ extern int smp_hw_index[]; -#define raw_smp_processor_id() (current_thread_info()->cpu) +/* + * This is particularly ugly: it appears we can't actually get the definition + * of task_struct here, but we need access to the CPU this task is running on. + * Instead of using task_struct we're using _TASK_CPU which is extracted from + * asm-offsets.h by kbuild to get the current processor ID. + * + * This also needs to be safeguarded when building asm-offsets.s because at + * that time _TASK_CPU is not defined yet. It could have been guarded by + * _TASK_CPU itself, but we want the build to fail if _TASK_CPU is missing + * when building something else than asm-offsets.s + */ +#ifdef GENERATING_ASM_OFFSETS +#define raw_smp_processor_id() (0) +#else +#define raw_smp_processor_id() (*(unsigned int *)((void *)current + _TASK_CPU)) +#endif #define hard_smp_processor_id() (smp_hw_index[smp_processor_id()]) static inline int get_hard_smp_processor_id(int cpu) 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 |