uprobes: Introduce copy_opcode(), kill read_opcode() (cceb55aa) · Commits · 戴 / test

kernel/events/uprobes.c

+19 −44

Original line number	Diff line number	Diff line
		@@ -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)

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