target/linux/uml/patches-4.9/003-um-Fix-check-for-_xstate-for-older-hosts.patch

   1 From 2fb44600fe784449404c6639de26af8361999ec7 Mon Sep 17 00:00:00 2001
   2 From: Florian Fainelli <f.fainelli@gmail.com>
   3 Date: Tue, 18 Jul 2017 16:43:47 -0700
   4 Subject: [PATCH] um: Fix check for _xstate for older hosts
   5
   6 Commit 0a987645672e ("um: Allow building and running on older
   7 hosts") attempted to check for PTRACE_{GET,SET}REGSET under the premise
   8 that these ptrace(2) parameters were directly linked with the presence
   9 of the _xstate structure.
  10
  11 After Richard's commit 61e8d462457f ("um: Correctly check for
  12 PTRACE_GETRESET/SETREGSET") which properly included linux/ptrace.h
  13 instead of asm/ptrace.h, we could get into the original build failure
  14 that I reported:
  15
  16 arch/x86/um/user-offsets.c: In function 'foo':
  17 arch/x86/um/user-offsets.c:54: error: invalid application of 'sizeof' to
  18 incomplete type 'struct _xstate'
  19
  20 On this particular host, we do have PTRACE_GETREGSET and
  21 PTRACE_SETREGSET defined in linux/ptrace.h, but not the structure
  22 _xstate that should be pulled from the following include chain: signal.h
  23 -> bits/sigcontext.h.
  24
  25 Correctly fix this by checking for FP_XSTATE_MAGIC1 which is the correct
  26 way to see if struct _xstate is available or not on the host.
  27
  28 Fixes: 61e8d462457f ("um: Correctly check for PTRACE_GETRESET/SETREGSET")
  29 Fixes: 0a987645672e ("um: Allow building and running on older hosts")
  30 Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
  31 Signed-off-by: Richard Weinberger <richard@nod.at>
  32 ---
  33  arch/x86/um/user-offsets.c | 2 +-
  34  1 file changed, 1 insertion(+), 1 deletion(-)
  35
  36 --- a/arch/x86/um/user-offsets.c
  37 +++ b/arch/x86/um/user-offsets.c
  38 @@ -50,7 +50,7 @@ void foo(void)
  39         DEFINE(HOST_GS, GS);
  40         DEFINE(HOST_ORIG_AX, ORIG_EAX);
  41  #else
  42 -#if defined(PTRACE_GETREGSET) && defined(PTRACE_SETREGSET)
  43 +#ifdef FP_XSTATE_MAGIC1
  44         DEFINE(HOST_FP_SIZE, sizeof(struct _xstate) / sizeof(unsigned long));
  45  #else
  46         DEFINE(HOST_FP_SIZE, sizeof(struct _fpstate) / sizeof(unsigned long));