diff options
| -rw-r--r-- | kernel/events/uprobes.c | 63 |
1 files changed, 19 insertions, 44 deletions
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index a4453d1..b6f0f71 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -183,19 +183,25 @@ bool __weak is_swbp_insn(uprobe_opcode_t *insn) return *insn == UPROBE_SWBP_INSN; } +static void copy_opcode(struct page *page, unsigned long vaddr, uprobe_opcode_t *opcode) +{ + void *kaddr = kmap_atomic(page); + memcpy(opcode, kaddr + (vaddr & ~PAGE_MASK), UPROBE_SWBP_INSN_SIZE); + kunmap_atomic(kaddr); +} + /* * NOTE: * Expect the breakpoint instruction to be the smallest size instruction for * the architecture. If an arch has variable length instruction and the * breakpoint instruction is not of the smallest length instruction - * supported by that architecture then we need to modify read_opcode / + * supported by that architecture then we need to modify is_swbp_at_addr and * write_opcode accordingly. This would never be a problem for archs that * have fixed length instructions. */ /* * write_opcode - write the opcode at a given virtual address. - * @auprobe: arch breakpointing information. * @mm: the probed process address space. * @vaddr: the virtual address to store the opcode. * @opcode: opcode to be written at @vaddr. @@ -206,8 +212,8 @@ bool __weak is_swbp_insn(uprobe_opcode_t *insn) * For mm @mm, write the opcode at @vaddr. * Return 0 (success) or a negative errno. */ -static int write_opcode(struct arch_uprobe *auprobe, struct mm_struct *mm, - unsigned long vaddr, uprobe_opcode_t opcode) +static int write_opcode(struct mm_struct *mm, unsigned long vaddr, + uprobe_opcode_t opcode) { struct page *old_page, *new_page; void *vaddr_old, *vaddr_new; @@ -253,40 +259,9 @@ put_old: return ret; } -/** - * read_opcode - read the opcode at a given virtual address. - * @mm: the probed process address space. - * @vaddr: the virtual address to read the opcode. - * @opcode: location to store the read opcode. - * - * Called with mm->mmap_sem held (for read and with a reference to - * mm. - * - * For mm @mm, read the opcode at @vaddr and store it in @opcode. - * Return 0 (success) or a negative errno. - */ -static int read_opcode(struct mm_struct *mm, unsigned long vaddr, uprobe_opcode_t *opcode) -{ - struct page *page; - void *vaddr_new; - int ret; - - ret = get_user_pages(NULL, mm, vaddr, 1, 0, 1, &page, NULL); - if (ret <= 0) - return ret; - - vaddr_new = kmap_atomic(page); - vaddr &= ~PAGE_MASK; - memcpy(opcode, vaddr_new + vaddr, UPROBE_SWBP_INSN_SIZE); - kunmap_atomic(vaddr_new); - - put_page(page); - - return 0; -} - static int is_swbp_at_addr(struct mm_struct *mm, unsigned long vaddr) { + struct page *page; uprobe_opcode_t opcode; int result; @@ -300,14 +275,14 @@ static int is_swbp_at_addr(struct mm_struct *mm, unsigned long vaddr) goto out; } - result = read_opcode(mm, vaddr, &opcode); - if (result) + result = get_user_pages(NULL, mm, vaddr, 1, 0, 1, &page, NULL); + if (result < 0) return result; -out: - if (is_swbp_insn(&opcode)) - return 1; - return 0; + copy_opcode(page, vaddr, &opcode); + put_page(page); + out: + return is_swbp_insn(&opcode); } /** @@ -321,7 +296,7 @@ out: */ int __weak set_swbp(struct arch_uprobe *auprobe, struct mm_struct *mm, unsigned long vaddr) { - return write_opcode(auprobe, mm, vaddr, UPROBE_SWBP_INSN); + return write_opcode(mm, vaddr, UPROBE_SWBP_INSN); } /** @@ -345,7 +320,7 @@ set_orig_insn(struct arch_uprobe *auprobe, struct mm_struct *mm, unsigned long v if (result != 1) return result; - return write_opcode(auprobe, mm, vaddr, *(uprobe_opcode_t *)auprobe->insn); + return write_opcode(mm, vaddr, *(uprobe_opcode_t *)auprobe->insn); } static int match_uprobe(struct uprobe *l, struct uprobe *r) |
