target/linux/uml/patches-4.9/001-um-Allow-building-and-running-on-older-hosts.patch

   1 From 0a987645672ebde7844a9c0732a5a25f3d4bb6c6 Mon Sep 17 00:00:00 2001
   2 From: Florian Fainelli <f.fainelli@gmail.com>
   3 Date: Thu, 25 May 2017 11:36:26 -0700
   4 Subject: [PATCH] um: Allow building and running on older hosts
   5
   6 [ Upstream commit 0a987645672ebde7844a9c0732a5a25f3d4bb6c6 ]
   7
   8 Commit a78ff1112263 ("um: add extended processor state save/restore
   9 support") and b6024b21fec8 ("um: extend fpstate to _xstate to support
  10 YMM registers") forced the use of the x86 FP _xstate and
  11 PTRACE_GETREGSET/SETREGSET. On older hosts, we would neither be able to
  12 build UML nor run it anymore with these two commits applied because we
  13 don't have definitions for struct _xstate nor these two ptrace requests.
  14
  15 We can determine at build time which fp context structure to check
  16 against, just like we can keep using the old i387 fp save/restore if
  17 PTRACE_GETRESET/SETREGSET are not defined.
  18
  19 Fixes: a78ff1112263 ("um: add extended processor state save/restore support")
  20 Fixes: b6024b21fec8 ("um: extend fpstate to _xstate to support YMM registers")
  21 Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
  22 Signed-off-by: Richard Weinberger <richard@nod.at>
  23 ---
  24  arch/x86/um/os-Linux/registers.c | 12 ++++++++----
  25  arch/x86/um/user-offsets.c       |  4 ++++
  26  2 files changed, 12 insertions(+), 4 deletions(-)
  27
  28 --- a/arch/x86/um/os-Linux/registers.c
  29 +++ b/arch/x86/um/os-Linux/registers.c
  30 @@ -26,6 +26,7 @@ int save_i387_registers(int pid, unsigne
  31
  32  int save_fp_registers(int pid, unsigned long *fp_regs)
  33  {
  34 +#ifdef PTRACE_GETREGSET
  35         struct iovec iov;
  36
  37         if (have_xstate_support) {
  38 @@ -34,9 +35,9 @@ int save_fp_registers(int pid, unsigned
  39                 if (ptrace(PTRACE_GETREGSET, pid, NT_X86_XSTATE, &iov) < 0)
  40                         return -errno;
  41                 return 0;
  42 -       } else {
  43 +       } else
  44 +#endif
  45                 return save_i387_registers(pid, fp_regs);
  46 -       }
  47  }
  48
  49  int restore_i387_registers(int pid, unsigned long *fp_regs)
  50 @@ -48,6 +49,7 @@ int restore_i387_registers(int pid, unsi
  51
  52  int restore_fp_registers(int pid, unsigned long *fp_regs)
  53  {
  54 +#ifdef PTRACE_SETREGSET
  55         struct iovec iov;
  56
  57         if (have_xstate_support) {
  58 @@ -56,9 +58,9 @@ int restore_fp_registers(int pid, unsign
  59                 if (ptrace(PTRACE_SETREGSET, pid, NT_X86_XSTATE, &iov) < 0)
  60                         return -errno;
  61                 return 0;
  62 -       } else {
  63 +       } else
  64 +#endif
  65                 return restore_i387_registers(pid, fp_regs);
  66 -       }
  67  }
  68
  69  #ifdef __i386__
  70 @@ -122,6 +124,7 @@ int put_fp_registers(int pid, unsigned l
  71
  72  void arch_init_registers(int pid)
  73  {
  74 +#ifdef PTRACE_GETREGSET
  75         struct _xstate fp_regs;
  76         struct iovec iov;
  77
  78 @@ -129,6 +132,7 @@ void arch_init_registers(int pid)
  79         iov.iov_len = sizeof(struct _xstate);
  80         if (ptrace(PTRACE_GETREGSET, pid, NT_X86_XSTATE, &iov) == 0)
  81                 have_xstate_support = 1;
  82 +#endif
  83  }
  84  #endif
  85
  86 --- a/arch/x86/um/user-offsets.c
  87 +++ b/arch/x86/um/user-offsets.c
  88 @@ -50,7 +50,11 @@ void foo(void)
  89         DEFINE(HOST_GS, GS);
  90         DEFINE(HOST_ORIG_AX, ORIG_EAX);
  91  #else
  92 +#if defined(PTRACE_GETREGSET) && defined(PTRACE_SETREGSET)
  93         DEFINE(HOST_FP_SIZE, sizeof(struct _xstate) / sizeof(unsigned long));
  94 +#else
  95 +       DEFINE(HOST_FP_SIZE, sizeof(struct _fpstate) / sizeof(unsigned long));
  96 +#endif
  97         DEFINE_LONGS(HOST_BX, RBX);
  98         DEFINE_LONGS(HOST_CX, RCX);
  99         DEFINE_LONGS(HOST_DI, RDI);