Commit f8b7c528 authored by Jiri Olsa's avatar Jiri Olsa Committed by Peter Zijlstra
Browse files

uprobes: Add nbytes argument to uprobe_write 



Adding nbytes argument to uprobe_write and related functions as
preparation for writing whole instructions in following changes.

Also renaming opcode arguments to insn, which seems to fit better.

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/20250720112133.244369-6-jolsa@kernel.org
parent 33d7b2be

include/linux/uprobes.h

+2 −2
Original line number Diff line number Diff line
@@ -188,7 +188,7 @@ struct uprobes_state { 
};



typedef int (*uprobe_write_verify_t)(struct page *page, unsigned long vaddr,

				     uprobe_opcode_t *opcode);

				     uprobe_opcode_t *insn, int nbytes);



extern void __init uprobes_init(void);

extern int set_swbp(struct arch_uprobe *aup, struct vm_area_struct *vma, unsigned long vaddr);
@@ -199,7 +199,7 @@ 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(struct arch_uprobe *auprobe, struct vm_area_struct *vma, const unsigned long opcode_vaddr,

			uprobe_opcode_t opcode, uprobe_write_verify_t verify);

			uprobe_opcode_t *insn, int nbytes, uprobe_write_verify_t verify);

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

+14 −12
Original line number Diff line number Diff line
@@ -191,7 +191,8 @@ static void copy_to_page(struct page *page, unsigned long vaddr, const void *src 
	kunmap_atomic(kaddr);

}



static int verify_opcode(struct page *page, unsigned long vaddr, uprobe_opcode_t *new_opcode)

static int verify_opcode(struct page *page, unsigned long vaddr, uprobe_opcode_t *insn,

			 int nbytes)

{

	uprobe_opcode_t old_opcode;

	bool is_swbp;
@@ -208,7 +209,7 @@ static int verify_opcode(struct page *page, unsigned long vaddr, uprobe_opcode_t 
	uprobe_copy_from_page(page, vaddr, &old_opcode, UPROBE_SWBP_INSN_SIZE);

	is_swbp = is_swbp_insn(&old_opcode);



	if (is_swbp_insn(new_opcode)) {

	if (is_swbp_insn(insn)) {

		if (is_swbp)		/* register: already installed? */

			return 0;

	} else {
@@ -401,10 +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 opcode_vaddr, uprobe_opcode_t opcode)

		unsigned long insn_vaddr, uprobe_opcode_t *insn, int nbytes)

{

	const unsigned long vaddr = opcode_vaddr & PAGE_MASK;

	const bool is_register = !!is_swbp_insn(&opcode);

	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. */
@@ -429,7 +430,7 @@ static int __uprobe_write(struct vm_area_struct *vma, 
	 */

	flush_cache_page(vma, vaddr, pte_pfn(fw->pte));

	fw->pte = ptep_clear_flush(vma, vaddr, fw->ptep);

	copy_to_page(fw->page, opcode_vaddr, &opcode, UPROBE_SWBP_INSN_SIZE);

	copy_to_page(fw->page, insn_vaddr, insn, nbytes);



	/*

	 * When unregistering, we may only zap a PTE if uffd is disabled and
@@ -488,13 +489,14 @@ static int __uprobe_write(struct vm_area_struct *vma, 
int uprobe_write_opcode(struct arch_uprobe *auprobe, struct vm_area_struct *vma,

		const unsigned long opcode_vaddr, uprobe_opcode_t opcode)

{

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

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

}



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

		 const unsigned long opcode_vaddr, uprobe_opcode_t opcode, uprobe_write_verify_t verify)

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

		 uprobe_write_verify_t verify)

{

	const unsigned long vaddr = opcode_vaddr & PAGE_MASK;

	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;
@@ -504,7 +506,7 @@ int uprobe_write(struct arch_uprobe *auprobe, struct vm_area_struct *vma, 
	struct folio *folio;

	struct page *page;



	is_register = is_swbp_insn(&opcode);

	is_register = is_swbp_insn(insn);

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



	if (WARN_ON_ONCE(!is_cow_mapping(vma->vm_flags)))
@@ -527,7 +529,7 @@ int uprobe_write(struct arch_uprobe *auprobe, struct vm_area_struct *vma, 
		goto out;

	folio = page_folio(page);



	ret = verify(page, opcode_vaddr, &opcode);

	ret = verify(page, insn_vaddr, insn, nbytes);

	if (ret <= 0) {

		folio_put(folio);

		goto out;
@@ -566,7 +568,7 @@ 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, opcode_vaddr, opcode);

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

		folio_walk_end(&fw, vma);

	}