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| author | Oleg Nesterov <oleg@redhat.com> | 2014-04-05 20:05:02 +0200 |
|---|---|---|
| committer | Oleg Nesterov <oleg@redhat.com> | 2014-04-17 21:58:22 +0200 |
| commit | 7ba6db2d688bdf83049a18c8e55b2d1e58e8b0bc (patch) | |
| tree | c2be845e50bb6057b8ea0716a18bca4120964060 /arch/x86/include/asm/uprobes.h | |
| parent | uprobes/x86: Introduce sizeof_long(), cleanup adjust_ret_addr() and arch_uret... (diff) | |
| download | linux-7ba6db2d688bdf83049a18c8e55b2d1e58e8b0bc.tar.xz linux-7ba6db2d688bdf83049a18c8e55b2d1e58e8b0bc.zip | |
uprobes/x86: Emulate unconditional relative jmp's
Currently we always execute all insns out-of-line, including relative
jmp's and call's. This assumes that even if regs->ip points to nowhere
after the single-step, default_post_xol_op(UPROBE_FIX_IP) logic will
update it correctly.
However, this doesn't work if this regs->ip == xol_vaddr + insn_offset
is not canonical. In this case CPU generates #GP and general_protection()
kills the task which tries to execute this insn out-of-line.
Now that we have uprobe_xol_ops we can teach uprobes to emulate these
insns and solve the problem. This patch adds branch_xol_ops which has
a single branch_emulate_op() hook, so far it can only handle rel8/32
relative jmp's.
TODO: move ->fixup into the union along with rip_rela_target_address.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reported-by: Jonathan Lebon <jlebon@redhat.com>
Reviewed-by: Jim Keniston <jkenisto@us.ibm.com>
Diffstat (limited to 'arch/x86/include/asm/uprobes.h')
| -rw-r--r-- | arch/x86/include/asm/uprobes.h | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/arch/x86/include/asm/uprobes.h b/arch/x86/include/asm/uprobes.h index 9f8210bcbb49..e9fd4d5537ed 100644 --- a/arch/x86/include/asm/uprobes.h +++ b/arch/x86/include/asm/uprobes.h @@ -44,9 +44,15 @@ struct arch_uprobe { u16 fixups; const struct uprobe_xol_ops *ops; + union { #ifdef CONFIG_X86_64 - unsigned long rip_rela_target_address; + unsigned long rip_rela_target_address; #endif + struct { + s32 offs; + u8 ilen; + } branch; + }; }; struct arch_uprobe_task { |