[PATCH RFC 2/3] kernel/events/uprobes: pass VMA to set_swbp(), set_orig_insn() and uprobe_write_opcode()

David Hildenbrand
2024-06-04T12:26:18Z

We already have the VMA, no need to look it up using
get_user_page_vma_remote(). We can now switch to
get_user_pages_remote().

Signed-off-by: David Hildenbrand <david@redhat.com>
---
arch/arm/probes/uprobes/core.c | 4 ++--
include/linux/uprobes.h | 6 +++---
kernel/events/uprobes.c | 33 +++++++++++++++++----------------
3 files changed, 22 insertions(+), 21 deletions(-)

diff --git a/arch/arm/probes/uprobes/core.c b/arch/arm/probes/uprobes/core.c
index f5f790c6e5f89..885e0c5e8c20d 100644
--- a/arch/arm/probes/uprobes/core.c
+++ b/arch/arm/probes/uprobes/core.c
@@ -26,10 +26,10 @@ bool is_swbp_insn(uprobe_opcode_t *insn)
(UPROBE_SWBP_ARM_INSN & 0x0fffffff);
}

-int set_swbp(struct arch_uprobe *auprobe, struct mm_struct *mm,
+int set_swbp(struct arch_uprobe *auprobe, struct vm_area_struct *vma,
unsigned long vaddr)
{
- return uprobe_write_opcode(auprobe, mm, vaddr,
+ return uprobe_write_opcode(auprobe, vma, vaddr,
__opcode_to_mem_arm(auprobe->bpinsn));
}

diff --git a/include/linux/uprobes.h b/include/linux/uprobes.h
index f46e0ca0169c7..77580dba6f8de 100644
--- a/include/linux/uprobes.h
+++ b/include/linux/uprobes.h
@@ -103,13 +103,13 @@ struct uprobes_state {
};

extern void __init uprobes_init(void);
-extern int set_swbp(struct arch_uprobe *aup, struct mm_struct *mm, unsigned long vaddr);
-extern int set_orig_insn(struct arch_uprobe *aup, struct mm_struct *mm, unsigned long vaddr);
+extern int set_swbp(struct arch_uprobe *aup, struct vm_area_struct *vma, unsigned long vaddr);
+extern int set_orig_insn(struct arch_uprobe *aup, struct vm_area_struct *vma, unsigned long vaddr);
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 vm_area_struct *vma, unsigned long vaddr, uprobe_opcode_t);
extern int uprobe_register(struct inode *inode, loff_t offset, struct uprobe_consumer *uc);
extern int uprobe_register_refctr(struct inode *inode, loff_t offset, loff_t ref_ctr_offset, struct uprobe_consumer *uc);
extern int uprobe_apply(struct inode *inode, loff_t offset, struct uprobe_consumer *uc, bool);
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index c6d6b7a8e4410..f2b1fef7f1d62 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -449,19 +449,19 @@ static int update_ref_ctr(struct uprobe *uprobe, struct mm_struct *mm,
*
* uprobe_write_opcode - write the opcode at a given virtual address.
* @auprobe: arch specific probepoint information.
- * @mm: the probed process address space.
+ * @vma: the probed virtual memory area.
* @vaddr: the virtual address to store the opcode.
* @opcode: opcode to be written at @vaddr.
*
* Called with mm->mmap_lock held for write.
* 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)
+int uprobe_write_opcode(struct arch_uprobe *auprobe, struct vm_area_struct *vma,
+ unsigned long vaddr, uprobe_opcode_t opcode)
{
+ struct mm_struct *mm = vma->vm_mm;
struct uprobe *uprobe;
struct page *old_page, *new_page;
- struct vm_area_struct *vma;
int ret, is_register, ref_ctr_updated = 0;
bool orig_page_huge = false;
unsigned int gup_flags = FOLL_FORCE;
@@ -473,9 +473,9 @@ int uprobe_write_opcode(struct arch_uprobe *auprobe, struct mm_struct *mm,
if (is_register)
gup_flags |= FOLL_SPLIT_PMD;
/* Read the page with vaddr into memory */
- old_page = get_user_page_vma_remote(mm, vaddr, gup_flags, &vma);
- if (IS_ERR(old_page))
- return PTR_ERR(old_page);
+ ret = get_user_pages_remote(mm, vaddr, 1, gup_flags, &old_page, NULL);
+ if (ret != 1)
+ return ret;

ret = verify_opcode(old_page, vaddr, &opcode);
if (ret <= 0)
@@ -560,30 +560,31 @@ int uprobe_write_opcode(struct arch_uprobe *auprobe, struct mm_struct *mm,
/**
* set_swbp - store breakpoint at a given address.
* @auprobe: arch specific probepoint information.
- * @mm: the probed process address space.
+ * @vma: the probed virtual memory area.
* @vaddr: the virtual address to insert the opcode.
*
* For mm @mm, store the breakpoint instruction at @vaddr.
* Return 0 (success) or a negative errno.
*/
-int __weak set_swbp(struct arch_uprobe *auprobe, struct mm_struct *mm, unsigned long vaddr)
+int __weak set_swbp(struct arch_uprobe *auprobe, struct vm_area_struct *vma,
+ unsigned long vaddr)
{
- return uprobe_write_opcode(auprobe, mm, vaddr, UPROBE_SWBP_INSN);
+ return uprobe_write_opcode(auprobe, vma, vaddr, UPROBE_SWBP_INSN);
}

/**
* set_orig_insn - Restore the original instruction.
- * @mm: the probed process address space.
+ * @vma: the probed virtual memory area.
* @auprobe: arch specific probepoint information.
* @vaddr: the virtual address to insert the opcode.
*
* For mm @mm, restore the original opcode (opcode) at @vaddr.
* Return 0 (success) or a negative errno.
*/
-int __weak
-set_orig_insn(struct arch_uprobe *auprobe, struct mm_struct *mm, unsigned long vaddr)
+int __weak set_orig_insn(struct arch_uprobe *auprobe,
+ struct vm_area_struct *vma, unsigned long vaddr)
{
- return uprobe_write_opcode(auprobe, mm, vaddr,
+ return uprobe_write_opcode(auprobe, vma, vaddr,
*(uprobe_opcode_t *)&auprobe->insn);
}

@@ -905,7 +906,7 @@ static int install_breakpoint(struct uprobe *uprobe, struct vm_area_struct *vma,
if (first_uprobe)
set_bit(MMF_HAS_UPROBES, &mm->flags);

- ret = set_swbp(&uprobe->arch, mm, vaddr);
+ ret = set_swbp(&uprobe->arch, vma, vaddr);
if (!ret)
clear_bit(MMF_RECALC_UPROBES, &mm->flags);
else if (first_uprobe)
@@ -920,7 +921,7 @@ static int remove_breakpoint(struct uprobe *uprobe, struct vm_area_struct *vma,
struct mm_struct *mm = vma->vm_mm;

set_bit(MMF_RECALC_UPROBES, &mm->flags);
- return set_orig_insn(&uprobe->arch, mm, vaddr);
+ return set_orig_insn(&uprobe->arch, vma, vaddr);
}

static inline bool uprobe_is_active(struct uprobe *uprobe)
--
2.45.1