uprobes: Don't assume that arch_uprobe->insn/ixol is u8[MAX_UINSN_BYTES]

arch_uprobe should be opaque as much as possible to the generic
code, but currently it assumes that insn/ixol must be u8[] of the
known size. Remove this unnecessary dependency, we can use "&" and
and sizeof() with the same effect.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>

diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index df4ef09..445962a 100644 (file)
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -330,7 +330,7 @@ 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 uprobe_write_opcode(mm, vaddr, *(uprobe_opcode_t *)auprobe->insn);
+       return uprobe_write_opcode(mm, vaddr, *(uprobe_opcode_t *)&auprobe->insn);
 }
 
 static int match_uprobe(struct uprobe *l, struct uprobe *r)
@@ -529,8 +529,8 @@ static int copy_insn(struct uprobe *uprobe, struct file *filp)
 {
        struct address_space *mapping = uprobe->inode->i_mapping;
        loff_t offs = uprobe->offset;
-       void *insn = uprobe->arch.insn;
-       int size = MAX_UINSN_BYTES;
+       void *insn = &uprobe->arch.insn;
+       int size = sizeof(uprobe->arch.insn);
        int len, err = -EIO;
 
        /* Copy only available bytes, -EIO if nothing was read */
@@ -569,7 +569,7 @@ static int prepare_uprobe(struct uprobe *uprobe, struct file *file,
                goto out;
 
        ret = -ENOTSUPP;
-       if (is_trap_insn((uprobe_opcode_t *)uprobe->arch.insn))
+       if (is_trap_insn((uprobe_opcode_t *)&uprobe->arch.insn))
                goto out;
 
        ret = arch_uprobe_analyze_insn(&uprobe->arch, mm, vaddr);
@@ -1264,7 +1264,7 @@ static unsigned long xol_get_insn_slot(struct uprobe *uprobe)
 
        /* Initialize the slot */
        copy_to_page(area->page, xol_vaddr,
-                       uprobe->arch.ixol, sizeof(uprobe->arch.ixol));
+                       &uprobe->arch.ixol, sizeof(uprobe->arch.ixol));
        /*
         * We probably need flush_icache_user_range() but it needs vma.
         * This should work on supported architectures too.