linux-kernel - [PATCH bpf-next 03/13] uprobes: Add nbytes argument to uprobe_write

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Message-ID: <20241211133403.208920-4-jolsa@kernel.org>
Date: Wed, 11 Dec 2024 14:33:52 +0100
From: Jiri Olsa <jolsa@...nel.org>
To: Oleg Nesterov <oleg@...hat.com>,
	Peter Zijlstra <peterz@...radead.org>,
	Andrii Nakryiko <andrii@...nel.org>
Cc: bpf@...r.kernel.org,
	Song Liu <songliubraving@...com>,
	Yonghong Song <yhs@...com>,
	John Fastabend <john.fastabend@...il.com>,
	Hao Luo <haoluo@...gle.com>,
	Steven Rostedt <rostedt@...dmis.org>,
	Masami Hiramatsu <mhiramat@...nel.org>,
	Alan Maguire <alan.maguire@...cle.com>,
	linux-kernel@...r.kernel.org,
	linux-trace-kernel@...r.kernel.org
Subject: [PATCH bpf-next 03/13] uprobes: Add nbytes argument to uprobe_write_opcode

Adding nbytes argument to uprobe_write_opcode as preparation
fo writing longer instructions in following changes.

Signed-off-by: Jiri Olsa <jolsa@...nel.org>
---
 include/linux/uprobes.h |  3 ++-
 kernel/events/uprobes.c | 14 ++++++++------
 2 files changed, 10 insertions(+), 7 deletions(-)

diff --git a/include/linux/uprobes.h b/include/linux/uprobes.h
index e24fbe496efb..cc723bc48c1d 100644
--- a/include/linux/uprobes.h
+++ b/include/linux/uprobes.h
@@ -181,7 +181,8 @@ 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 mm_struct *mm, unsigned long vaddr, uprobe_opcode_t);
+extern int uprobe_write_opcode(struct arch_uprobe *auprobe, struct mm_struct *mm, unsigned long vaddr,
+			       uprobe_opcode_t *insn, int nbytes);
 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);
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index 61ec91f635dc..7c2ecf11a573 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -470,7 +470,7 @@ static int update_ref_ctr(struct uprobe *uprobe, struct mm_struct *mm,
  * Return 0 (success) or a negative errno.
  */
 int uprobe_write_opcode(struct arch_uprobe *auprobe, struct mm_struct *mm,
-			unsigned long vaddr, uprobe_opcode_t opcode)
+			unsigned long vaddr, uprobe_opcode_t *insn, int nbytes)
 {
 	struct uprobe *uprobe;
 	struct page *old_page, *new_page;
@@ -479,7 +479,7 @@ int uprobe_write_opcode(struct arch_uprobe *auprobe, struct mm_struct *mm,
 	bool orig_page_huge = false;
 	unsigned int gup_flags = FOLL_FORCE;
 
-	is_register = is_swbp_insn(&opcode);
+	is_register = is_swbp_insn(insn);
 	uprobe = container_of(auprobe, struct uprobe, arch);
 
 retry:
@@ -490,7 +490,7 @@ int uprobe_write_opcode(struct arch_uprobe *auprobe, struct mm_struct *mm,
 	if (IS_ERR(old_page))
 		return PTR_ERR(old_page);
 
-	ret = verify_opcode(old_page, vaddr, &opcode);
+	ret = verify_opcode(old_page, vaddr, insn);
 	if (ret <= 0)
 		goto put_old;
 
@@ -524,7 +524,7 @@ int uprobe_write_opcode(struct arch_uprobe *auprobe, struct mm_struct *mm,
 
 	__SetPageUptodate(new_page);
 	copy_highpage(new_page, old_page);
-	uprobe_copy_to_page(new_page, vaddr, &opcode, UPROBE_SWBP_INSN_SIZE);
+	uprobe_copy_to_page(new_page, vaddr, insn, nbytes);
 
 	if (!is_register) {
 		struct page *orig_page;
@@ -581,7 +581,9 @@ int uprobe_write_opcode(struct arch_uprobe *auprobe, struct mm_struct *mm,
  */
 int __weak set_swbp(struct arch_uprobe *auprobe, struct mm_struct *mm, unsigned long vaddr)
 {
-	return uprobe_write_opcode(auprobe, mm, vaddr, UPROBE_SWBP_INSN);
+	uprobe_opcode_t insn = UPROBE_SWBP_INSN;
+
+	return uprobe_write_opcode(auprobe, mm, vaddr, &insn, UPROBE_SWBP_INSN_SIZE);
 }
 
 /**
@@ -597,7 +599,7 @@ int __weak
 set_orig_insn(struct arch_uprobe *auprobe, struct mm_struct *mm, unsigned long vaddr)
 {
 	return uprobe_write_opcode(auprobe, mm, vaddr,
-			*(uprobe_opcode_t *)&auprobe->insn);
+			(uprobe_opcode_t *)&auprobe->insn, UPROBE_SWBP_INSN_SIZE);
 }
 
 /* uprobe should have guaranteed positive refcount */
-- 
2.47.0