diff options
| author | Josh Poimboeuf <jpoimboe@kernel.org> | 2023-06-05 09:12:22 -0700 |
|---|---|---|
| committer | Josh Poimboeuf <jpoimboe@kernel.org> | 2023-06-07 10:03:12 -0700 |
| commit | a9da8247627eefc73f909bf945031a5431a53993 (patch) | |
| tree | 7f4ad803471dc7823978c654e452b69c2908dbf1 /drivers/gpu/drm/vmwgfx | |
| parent | 1e4b619185e83e54aca617cf5070c64a88fe936b (diff) | |
drm/vmwgfx: Add unwind hints around RBP clobber
VMware high-bandwidth hypercalls take the RBP register as input. This
breaks basic frame pointer convention, as RBP should never be clobbered.
So frame pointer unwinding is broken for the instructions surrounding
the hypercalls. Fortunately this doesn't break live patching with
CONFIG_FRAME_POINTER, as it only unwinds from blocking tasks, and stack
traces from preempted tasks are already marked unreliable anyway.
However, for live patching with ORC, this could actually be a
theoretical problem if vmw_port_hb_{in,out}() were still compiled with a
frame pointer due to having an aligned stack. In practice that hasn't
seemed to be an issue since the objtool warnings have only been seen
with CONFIG_FRAME_POINTER.
Add unwind hint annotations to tell the ORC unwinder to mark stack
traces as unreliable.
Fixes the following warnings:
vmlinux.o: warning: objtool: vmw_port_hb_in+0x1df: return with modified stack frame
vmlinux.o: warning: objtool: vmw_port_hb_out+0x1dd: return with modified stack frame
Fixes: 89da76fde68d ("drm/vmwgfx: Add VMWare host messaging capability")
Reported-by: kernel test robot <lkp@intel.com>
Link: https://lore.kernel.org/oe-kbuild-all/202305160135.97q0Elax-lkp@intel.com/
Link: https://lore.kernel.org/r/4c795f2d87bc0391cf6543bcb224fa540b55ce4b.1685981486.git.jpoimboe@kernel.org
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Diffstat (limited to 'drivers/gpu/drm/vmwgfx')
| -rw-r--r-- | drivers/gpu/drm/vmwgfx/vmwgfx_msg_x86.h | 16 |
1 files changed, 12 insertions, 4 deletions
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_msg_x86.h b/drivers/gpu/drm/vmwgfx/vmwgfx_msg_x86.h index 0b74ca2dfb7b..23899d743a90 100644 --- a/drivers/gpu/drm/vmwgfx/vmwgfx_msg_x86.h +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_msg_x86.h @@ -105,10 +105,14 @@ flags, magic, bp, \ eax, ebx, ecx, edx, si, di) \ ({ \ - asm volatile ("push %%rbp;" \ + asm volatile ( \ + UNWIND_HINT_SAVE \ + "push %%rbp;" \ + UNWIND_HINT_UNDEFINED \ "mov %12, %%rbp;" \ VMWARE_HYPERCALL_HB_OUT \ - "pop %%rbp;" : \ + "pop %%rbp;" \ + UNWIND_HINT_RESTORE : \ "=a"(eax), \ "=b"(ebx), \ "=c"(ecx), \ @@ -130,10 +134,14 @@ flags, magic, bp, \ eax, ebx, ecx, edx, si, di) \ ({ \ - asm volatile ("push %%rbp;" \ + asm volatile ( \ + UNWIND_HINT_SAVE \ + "push %%rbp;" \ + UNWIND_HINT_UNDEFINED \ "mov %12, %%rbp;" \ VMWARE_HYPERCALL_HB_IN \ - "pop %%rbp" : \ + "pop %%rbp;" \ + UNWIND_HINT_RESTORE : \ "=a"(eax), \ "=b"(ebx), \ "=c"(ecx), \ |