From: Rabin Vincent rabin@rab.in

Allow arches to write the opcode with a custom function. ARM needs to customize the swbp instruction depending on the condition code of the instruction it replaces.

Signed-off-by: Rabin Vincent rabin@rab.in Signed-off-by: David A. Long dave.long@linaro.org --- include/linux/uprobes.h | 3 +++ kernel/events/uprobes.c | 16 ++++++++++++---- 2 files changed, 15 insertions(+), 4 deletions(-)

diff --git a/include/linux/uprobes.h b/include/linux/uprobes.h index e5a9bfb..5eef2f0 100644 --- a/include/linux/uprobes.h +++ b/include/linux/uprobes.h @@ -136,6 +136,9 @@ extern void arch_uprobe_abort_xol(struct arch_uprobe *aup, struct pt_regs *regs) extern bool __weak arch_uprobe_ignore(struct arch_uprobe *aup, struct pt_regs *regs); extern void __weak arch_uprobe_xol_copy(struct arch_uprobe *auprobe, void *vaddr); extern int __weak arch_uprobes_init(void); +extern void __weak arch_uprobe_write_opcode(struct arch_uprobe *auprobe, + void *vaddr, + uprobe_opcode_t opcode); #else /* !CONFIG_UPROBES */ struct uprobes_state { }; diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index 5004f6f..3b2f764 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -248,6 +248,12 @@ static int verify_opcode(struct page *page, unsigned long vaddr, uprobe_opcode_t * have fixed length instructions. */

+void __weak arch_uprobe_write_opcode(struct arch_uprobe *auprobe, void *vaddr, + uprobe_opcode_t opcode) +{ + memcpy(vaddr, &opcode, UPROBE_SWBP_INSN_SIZE); +} + /* * write_opcode - write the opcode at a given virtual address. * @mm: the probed process address space. @@ -260,7 +266,7 @@ static int verify_opcode(struct page *page, unsigned long vaddr, uprobe_opcode_t * For mm @mm, write the opcode at @vaddr. * Return 0 (success) or a negative errno. */ -static int write_opcode(struct mm_struct *mm, unsigned long vaddr, +static int write_opcode(struct arch_uprobe *auprobe, struct mm_struct *mm, unsigned long vaddr, uprobe_opcode_t opcode) { struct page *old_page, *new_page; @@ -285,7 +291,9 @@ retry: __SetPageUptodate(new_page);

copy_highpage(new_page, old_page); - copy_to_page(new_page, vaddr, &opcode, UPROBE_SWBP_INSN_SIZE); + vaddr_new = kmap_atomic(new_page); + arch_uprobe_write_opcode(auprobe, vaddr_new + (vaddr & ~PAGE_MASK), opcode); + kunmap_atomic(vaddr_new);

ret = anon_vma_prepare(vma); if (ret) @@ -314,7 +322,7 @@ put_old: */ int __weak set_swbp(struct arch_uprobe *auprobe, struct mm_struct *mm, unsigned long vaddr) { - return write_opcode(mm, vaddr, UPROBE_SWBP_INSN); + return write_opcode(auprobe, mm, vaddr, UPROBE_SWBP_INSN); }

/** @@ -329,7 +337,7 @@ int __weak set_swbp(struct arch_uprobe *auprobe, struct mm_struct *mm, unsigned int __weak set_orig_insn(struct arch_uprobe *auprobe, struct mm_struct *mm, unsigned long vaddr) { - return write_opcode(mm, vaddr, *(uprobe_opcode_t *)auprobe->insn); + return write_opcode(auprobe, mm, vaddr, *(uprobe_opcode_t *)auprobe->insn); }

static int match_uprobe(struct uprobe *l, struct uprobe *r)