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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: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Link: https://lore.kernel.org/r/20250720112133.244369-7-jolsa@kernel.org
pull/1354/merge
Jiri Olsa 2025-07-20 13:21:16 +02:00 committed by Peter Zijlstra
parent f8b7c528b4
commit ec46350fe1
3 changed files with 15 additions and 13 deletions
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2
arch/arm/probes/uprobes/core.c
View File

@ -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)

5
include/linux/uprobes.h
View File

@ -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);

21
kernel/events/uprobes.c
View File

@ -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 @@ remap:
* 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 @@ retry:
/* 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 @@ out:
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 */