From 3247343118daa73f2b94b7fa565425d1d9f9ac84 Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Fri, 8 Nov 2013 18:52:21 +0100 Subject: uprobes: Add uprobe_task->dup_xol_work/dup_xol_addr uprobe_task->vaddr is a bit strange. The generic code uses it only to pass the additional argument to arch_uprobe_pre_xol(), and since it is always equal to instruction_pointer() this looks even more strange. And both utask->vaddr and and utask->autask have the same scope, they only have the meaning when the task executes the probed insn out-of-line, so it is safe to reuse both in UTASK_RUNNING state. This all means that logically ->vaddr belongs to arch_uprobe_task and we should probably move it there, arch_uprobe_pre_xol() can record instruction_pointer() itself. OTOH, it is also used by uprobe_copy_process() and dup_xol_work() for another purpose, this doesn't look clean and doesn't allow to move this member into arch_uprobe_task. This patch adds the union with 2 anonymous structs into uprobe_task. The first struct is autask + vaddr, this way we "almost" move vaddr into autask. The second struct has 2 new members for uprobe_copy_process() paths: ->dup_xol_addr which can be used instead ->vaddr, and ->dup_xol_work which can be used to avoid kmalloc() and simplify the code. Note that this union will likely have another member(s), we need something like "private_data_for_handlers" so that the tracing handlers could use it to communicate with call_fetch() methods. Signed-off-by: Oleg Nesterov Reviewed-by: Masami Hiramatsu Acked-by: Srikar Dronamraju --- include/linux/uprobes.h | 21 ++++++++++++++++----- 1 file changed, 16 insertions(+), 5 deletions(-) (limited to 'include/linux') diff --git a/include/linux/uprobes.h b/include/linux/uprobes.h index 319eae70fe84..2225542624de 100644 --- a/include/linux/uprobes.h +++ b/include/linux/uprobes.h @@ -26,6 +26,7 @@ #include #include +#include struct vm_area_struct; struct mm_struct; @@ -72,14 +73,24 @@ enum uprobe_task_state { */ struct uprobe_task { enum uprobe_task_state state; - struct arch_uprobe_task autask; - struct return_instance *return_instances; - unsigned int depth; - struct uprobe *active_uprobe; + union { + struct { + struct arch_uprobe_task autask; + unsigned long vaddr; + }; + + struct { + struct callback_head dup_xol_work; + unsigned long dup_xol_addr; + }; + }; + struct uprobe *active_uprobe; unsigned long xol_vaddr; - unsigned long vaddr; + + struct return_instance *return_instances; + unsigned int depth; }; /* -- cgit v1.2.3 From c912dae60ae6f659455f239298110adc67a5f3e9 Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Sat, 9 Nov 2013 19:49:39 +0100 Subject: uprobes: Cleanup !CONFIG_UPROBES decls, unexport xol_area 1. Don't include asm/uprobes.h unconditionally, we only need it if CONFIG_UPROBES. 2. Move the definition of "struct xol_area" into uprobes.c. Perhaps we should simply kill struct uprobes_state, it buys nothing. 3. Kill the dummy definition of uprobe_get_swbp_addr(), nobody except handle_swbp() needs it. 4. Purely cosmetic, but move the decl of uprobe_get_swbp_addr() up, close to other __weak helpers. Signed-off-by: Oleg Nesterov Acked-by: Srikar Dronamraju --- include/linux/uprobes.h | 31 ++++--------------------------- kernel/events/uprobes.c | 19 +++++++++++++++++++ 2 files changed, 23 insertions(+), 27 deletions(-) (limited to 'include/linux') diff --git a/include/linux/uprobes.h b/include/linux/uprobes.h index 2225542624de..e32251e00e62 100644 --- a/include/linux/uprobes.h +++ b/include/linux/uprobes.h @@ -33,10 +33,6 @@ struct mm_struct; struct inode; struct notifier_block; -#ifdef CONFIG_ARCH_SUPPORTS_UPROBES -# include -#endif - #define UPROBE_HANDLER_REMOVE 1 #define UPROBE_HANDLER_MASK 1 @@ -61,6 +57,8 @@ struct uprobe_consumer { }; #ifdef CONFIG_UPROBES +#include + enum uprobe_task_state { UTASK_RUNNING, UTASK_SSTEP, @@ -93,24 +91,7 @@ struct uprobe_task { unsigned int depth; }; -/* - * On a breakpoint hit, thread contests for a slot. It frees the - * slot after singlestep. Currently a fixed number of slots are - * allocated. - */ -struct xol_area { - wait_queue_head_t wq; /* if all slots are busy */ - atomic_t slot_count; /* number of in-use slots */ - unsigned long *bitmap; /* 0 = free slot */ - struct page *page; - - /* - * We keep the vma's vm_start rather than a pointer to the vma - * itself. The probed process or a naughty kernel module could make - * the vma go away, and we must handle that reasonably gracefully. - */ - unsigned long vaddr; /* Page(s) of instruction slots */ -}; +struct xol_area; struct uprobes_state { struct xol_area *xol_area; @@ -120,6 +101,7 @@ extern int __weak set_swbp(struct arch_uprobe *aup, struct mm_struct *mm, unsign extern int __weak set_orig_insn(struct arch_uprobe *aup, struct mm_struct *mm, unsigned long vaddr); extern bool __weak is_swbp_insn(uprobe_opcode_t *insn); extern bool __weak is_trap_insn(uprobe_opcode_t *insn); +extern unsigned long __weak uprobe_get_swbp_addr(struct pt_regs *regs); extern int uprobe_write_opcode(struct mm_struct *mm, unsigned long vaddr, uprobe_opcode_t); extern int uprobe_register(struct inode *inode, loff_t offset, struct uprobe_consumer *uc); extern int uprobe_apply(struct inode *inode, loff_t offset, struct uprobe_consumer *uc, bool); @@ -131,7 +113,6 @@ extern void uprobe_end_dup_mmap(void); extern void uprobe_dup_mmap(struct mm_struct *oldmm, struct mm_struct *newmm); extern void uprobe_free_utask(struct task_struct *t); extern void uprobe_copy_process(struct task_struct *t, unsigned long flags); -extern unsigned long __weak uprobe_get_swbp_addr(struct pt_regs *regs); extern int uprobe_post_sstep_notifier(struct pt_regs *regs); extern int uprobe_pre_sstep_notifier(struct pt_regs *regs); extern void uprobe_notify_resume(struct pt_regs *regs); @@ -187,10 +168,6 @@ static inline bool uprobe_deny_signal(void) { return false; } -static inline unsigned long uprobe_get_swbp_addr(struct pt_regs *regs) -{ - return 0; -} static inline void uprobe_free_utask(struct task_struct *t) { } diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index 445962a72498..51a7f535ff96 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -85,6 +85,25 @@ struct return_instance { struct return_instance *next; /* keep as stack */ }; +/* + * On a breakpoint hit, thread contests for a slot. It frees the + * slot after singlestep. Currently a fixed number of slots are + * allocated. + */ +struct xol_area { + wait_queue_head_t wq; /* if all slots are busy */ + atomic_t slot_count; /* number of in-use slots */ + unsigned long *bitmap; /* 0 = free slot */ + struct page *page; + + /* + * We keep the vma's vm_start rather than a pointer to the vma + * itself. The probed process or a naughty kernel module could make + * the vma go away, and we must handle that reasonably gracefully. + */ + unsigned long vaddr; /* Page(s) of instruction slots */ +}; + /* * valid_vma: Verify if the specified vma is an executable vma * Relax restrictions while unregistering: vm_flags might have -- cgit v1.2.3