Commit ec46350f authored by Jiri Olsa's avatar Jiri Olsa Committed by Peter Zijlstra
Browse files

uprobes: Add is_register argument to uprobe_write and uprobe_write_opcode 



The uprobe_write has special path to restore the original page when we
write original instruction back. This happens when uprobe_write detects
that we want to write anything else but breakpoint instruction.

Moving the detection away and passing it to uprobe_write as argument,
so it's possible to write different instructions (other than just
breakpoint and rest).

Signed-off-by: default avatarJiri Olsa <jolsa@kernel.org>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: default avatarMasami Hiramatsu (Google) <mhiramat@kernel.org>
Acked-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Acked-by: default avatarOleg Nesterov <oleg@redhat.com>
Link: https://lore.kernel.org/r/20250720112133.244369-7-jolsa@kernel.org
parent f8b7c528

arch/arm/probes/uprobes/core.c

+1 −1
Original line number Diff line number Diff line
@@ -30,7 +30,7 @@ int set_swbp(struct arch_uprobe *auprobe, struct vm_area_struct *vma, 
	     unsigned long vaddr)

{

	return uprobe_write_opcode(auprobe, vma, vaddr,

		   __opcode_to_mem_arm(auprobe->bpinsn));

		   __opcode_to_mem_arm(auprobe->bpinsn), true);

}



bool arch_uprobe_ignore(struct arch_uprobe *auprobe, struct pt_regs *regs)

include/linux/uprobes.h

+3 −2
Original line number Diff line number Diff line
@@ -197,9 +197,10 @@ extern bool is_swbp_insn(uprobe_opcode_t *insn); 
extern bool is_trap_insn(uprobe_opcode_t *insn);

extern unsigned long uprobe_get_swbp_addr(struct pt_regs *regs);

extern unsigned long uprobe_get_trap_addr(struct pt_regs *regs);

extern int uprobe_write_opcode(struct arch_uprobe *auprobe, struct vm_area_struct *vma, unsigned long vaddr, uprobe_opcode_t);

extern int uprobe_write_opcode(struct arch_uprobe *auprobe, struct vm_area_struct *vma, unsigned long vaddr, uprobe_opcode_t,

			       bool is_register);

extern int uprobe_write(struct arch_uprobe *auprobe, struct vm_area_struct *vma, const unsigned long opcode_vaddr,

			uprobe_opcode_t *insn, int nbytes, uprobe_write_verify_t verify);

			uprobe_opcode_t *insn, int nbytes, uprobe_write_verify_t verify, bool is_register);

extern struct uprobe *uprobe_register(struct inode *inode, loff_t offset, loff_t ref_ctr_offset, struct uprobe_consumer *uc);

extern int uprobe_apply(struct uprobe *uprobe, struct uprobe_consumer *uc, bool);

extern void uprobe_unregister_nosync(struct uprobe *uprobe, struct uprobe_consumer *uc);

kernel/events/uprobes.c

+11 −10
Original line number Diff line number Diff line
@@ -402,10 +402,10 @@ static bool orig_page_is_identical(struct vm_area_struct *vma, 


static int __uprobe_write(struct vm_area_struct *vma,

		struct folio_walk *fw, struct folio *folio,

		unsigned long insn_vaddr, uprobe_opcode_t *insn, int nbytes)

		unsigned long insn_vaddr, uprobe_opcode_t *insn, int nbytes,

		bool is_register)

{

	const unsigned long vaddr = insn_vaddr & PAGE_MASK;

	const bool is_register = !!is_swbp_insn(insn);

	bool pmd_mappable;



	/* For now, we'll only handle PTE-mapped folios. */
@@ -487,26 +487,27 @@ static int __uprobe_write(struct vm_area_struct *vma, 
 * Return 0 (success) or a negative errno.

 */

int uprobe_write_opcode(struct arch_uprobe *auprobe, struct vm_area_struct *vma,

		const unsigned long opcode_vaddr, uprobe_opcode_t opcode)

		const unsigned long opcode_vaddr, uprobe_opcode_t opcode,

		bool is_register)

{

	return uprobe_write(auprobe, vma, opcode_vaddr, &opcode, UPROBE_SWBP_INSN_SIZE, verify_opcode);

	return uprobe_write(auprobe, vma, opcode_vaddr, &opcode, UPROBE_SWBP_INSN_SIZE,

			    verify_opcode, is_register);

}



int uprobe_write(struct arch_uprobe *auprobe, struct vm_area_struct *vma,

		 const unsigned long insn_vaddr, uprobe_opcode_t *insn, int nbytes,

		 uprobe_write_verify_t verify)

		 uprobe_write_verify_t verify, bool is_register)

{

	const unsigned long vaddr = insn_vaddr & PAGE_MASK;

	struct mm_struct *mm = vma->vm_mm;

	struct uprobe *uprobe;

	int ret, is_register, ref_ctr_updated = 0;

	int ret, ref_ctr_updated = 0;

	unsigned int gup_flags = FOLL_FORCE;

	struct mmu_notifier_range range;

	struct folio_walk fw;

	struct folio *folio;

	struct page *page;



	is_register = is_swbp_insn(insn);

	uprobe = container_of(auprobe, struct uprobe, arch);



	if (WARN_ON_ONCE(!is_cow_mapping(vma->vm_flags)))
@@ -568,7 +569,7 @@ int uprobe_write(struct arch_uprobe *auprobe, struct vm_area_struct *vma, 
	/* Walk the page tables again, to perform the actual update. */

	if (folio_walk_start(&fw, vma, vaddr, 0)) {

		if (fw.page == page)

			ret = __uprobe_write(vma, &fw, folio, insn_vaddr, insn, nbytes);

			ret = __uprobe_write(vma, &fw, folio, insn_vaddr, insn, nbytes, is_register);

		folio_walk_end(&fw, vma);

	}
@@ -610,7 +611,7 @@ int uprobe_write(struct arch_uprobe *auprobe, struct vm_area_struct *vma, 
int __weak set_swbp(struct arch_uprobe *auprobe, struct vm_area_struct *vma,

		unsigned long vaddr)

{

	return uprobe_write_opcode(auprobe, vma, vaddr, UPROBE_SWBP_INSN);

	return uprobe_write_opcode(auprobe, vma, vaddr, UPROBE_SWBP_INSN, true);

}



/**
@@ -626,7 +627,7 @@ int __weak set_orig_insn(struct arch_uprobe *auprobe, 
		struct vm_area_struct *vma, unsigned long vaddr)

{

	return uprobe_write_opcode(auprobe, vma, vaddr,

			*(uprobe_opcode_t *)&auprobe->insn);

			*(uprobe_opcode_t *)&auprobe->insn, false);

}



/* uprobe should have guaranteed positive refcount */