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).
Acked-by: Andrii Nakryiko <and...@kernel.org>
Signed-off-by: Jiri Olsa <jo...@kernel.org>
---
arch/arm/probes/uprobes/core.c | 2 +-
include/linux/uprobes.h | 5 +++--
kernel/events/uprobes.c | 21 +++++++++++----------
3 files changed, 15 insertions(+), 13 deletions(-)
diff --git a/arch/arm/probes/uprobes/core.c b/arch/arm/probes/uprobes/core.c
index 885e0c5e8c20..3d96fb41d624 100644
--- a/arch/arm/probes/uprobes/core.c
+++ b/arch/arm/probes/uprobes/core.c
@@ -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)
diff --git a/include/linux/uprobes.h b/include/linux/uprobes.h
index 147c4a0a1af9..518b26756469 100644
--- a/include/linux/uprobes.h
+++ b/include/linux/uprobes.h
@@ -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);
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index f7feb7417a2c..1e5dc3b30707 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -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. */
@@ -488,26 +488,27 @@ 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)))
@@ -569,7 +570,7 @@ 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);
}
@@ -611,7 +612,7 @@ 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);
}
/**
@@ -627,7 +628,7 @@ 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 */
--
2.49.0
