target/linux/generic/backport-5.4/300-MIPS-Exclude-more-dsemul-code-when-CONFIG_MIPS_FP_SU.patch

   1 From d96c3157f9ca177727fbad960fcf6f52f145f471 Mon Sep 17 00:00:00 2001
   2 From: Yousong Zhou <yszhou4tech@gmail.com>
   3 Date: Thu, 9 Jan 2020 11:33:19 +0800
   4 Subject: [PATCH] MIPS: Exclude more dsemul code when CONFIG_MIPS_FP_SUPPORT=n
   5
   6 This furthers what commit 42b10815d559 ("MIPS: Don't compile math-emu
   7 when CONFIG_MIPS_FP_SUPPORT=n") has done
   8
   9 Signed-off-by: Yousong Zhou <yszhou4tech@gmail.com>
  10 ---
  11  arch/mips/include/asm/processor.h | 12 ++++++------
  12  arch/mips/kernel/process.c        | 10 ++++++++--
  13  arch/mips/kernel/vdso.c           | 26 +++++++++++++++-----------
  14  3 files changed, 29 insertions(+), 19 deletions(-)
  15
  16 diff --git a/arch/mips/include/asm/processor.h b/arch/mips/include/asm/processor.h
  17 index 7619ad319400..813ba94d87bb 100644
  18 --- a/arch/mips/include/asm/processor.h
  19 +++ b/arch/mips/include/asm/processor.h
  20 @@ -253,13 +253,13 @@ struct thread_struct {
  21  #ifdef CONFIG_MIPS_FP_SUPPORT
  22         /* Saved fpu/fpu emulator stuff. */
  23         struct mips_fpu_struct fpu FPU_ALIGN;
  24 -#endif
  25         /* Assigned branch delay slot 'emulation' frame */
  26         atomic_t bd_emu_frame;
  27         /* PC of the branch from a branch delay slot 'emulation' */
  28         unsigned long bd_emu_branch_pc;
  29         /* PC to continue from following a branch delay slot 'emulation' */
  30         unsigned long bd_emu_cont_pc;
  31 +#endif
  32  #ifdef CONFIG_MIPS_MT_FPAFF
  33         /* Emulated instruction count */
  34         unsigned long emulated_fp;
  35 @@ -302,7 +302,11 @@ struct thread_struct {
  36                 .fpr            = {{{0,},},},                   \
  37                 .fcr31          = 0,                            \
  38                 .msacsr         = 0,                            \
  39 -       },
  40 +       },                                                      \
  41 +       /* Delay slot emulation */                              \
  42 +       .bd_emu_frame = ATOMIC_INIT(BD_EMUFRAME_NONE),          \
  43 +       .bd_emu_branch_pc = 0,                                  \
  44 +       .bd_emu_cont_pc = 0,
  45  #else
  46  # define FPU_INIT
  47  #endif
  48 @@ -334,10 +338,6 @@ struct thread_struct {
  49          * FPU affinity state (null if not FPAFF)               \
  50          */                                                     \
  51         FPAFF_INIT                                              \
  52 -       /* Delay slot emulation */                              \
  53 -       .bd_emu_frame = ATOMIC_INIT(BD_EMUFRAME_NONE),          \
  54 -       .bd_emu_branch_pc = 0,                                  \
  55 -       .bd_emu_cont_pc = 0,                                    \
  56         /*                                                      \
  57          * Saved DSP stuff                                      \
  58          */                                                     \
  59 diff --git a/arch/mips/kernel/process.c b/arch/mips/kernel/process.c
  60 index 339870ed92f7..b2a797557825 100644
  61 --- a/arch/mips/kernel/process.c
  62 +++ b/arch/mips/kernel/process.c
  63 @@ -75,7 +75,9 @@ void start_thread(struct pt_regs * regs, unsigned long pc, unsigned long sp)
  64         lose_fpu(0);
  65         clear_thread_flag(TIF_MSA_CTX_LIVE);
  66         clear_used_math();
  67 +#ifdef CONFIG_MIPS_FP_SUPPORT
  68         atomic_set(&current->thread.bd_emu_frame, BD_EMUFRAME_NONE);
  69 +#endif
  70         init_dsp();
  71         regs->cp0_epc = pc;
  72         regs->regs[29] = sp;
  73 @@ -176,7 +178,9 @@ int copy_thread_tls(unsigned long clone_flags, unsigned long usp,
  74         clear_tsk_thread_flag(p, TIF_FPUBOUND);
  75  #endif /* CONFIG_MIPS_MT_FPAFF */
  76
  77 +#ifdef CONFIG_MIPS_FP_SUPPORT
  78         atomic_set(&p->thread.bd_emu_frame, BD_EMUFRAME_NONE);
  79 +#endif
  80
  81         if (clone_flags & CLONE_SETTLS)
  82                 ti->tp_value = tls;
  83 @@ -650,8 +654,10 @@ unsigned long mips_stack_top(void)
  84  {
  85         unsigned long top = TASK_SIZE & PAGE_MASK;
  86
  87 -       /* One page for branch delay slot "emulation" */
  88 -       top -= PAGE_SIZE;
  89 +       if (IS_ENABLED(CONFIG_MIPS_FP_SUPPORT)) {
  90 +               /* One page for branch delay slot "emulation" */
  91 +               top -= PAGE_SIZE;
  92 +       }
  93
  94         /* Space for the VDSO, data page & GIC user page */
  95         top -= PAGE_ALIGN(current->thread.abi->vdso->size);
  96 diff --git a/arch/mips/kernel/vdso.c b/arch/mips/kernel/vdso.c
  97 index bc35f8499111..3adb7354bc01 100644
  98 --- a/arch/mips/kernel/vdso.c
  99 +++ b/arch/mips/kernel/vdso.c
 100 @@ -71,10 +71,12 @@ subsys_initcall(init_vdso);
 101
 102  static unsigned long vdso_base(void)
 103  {
 104 -       unsigned long base;
 105 +       unsigned long base = STACK_TOP;
 106
 107 -       /* Skip the delay slot emulation page */
 108 -       base = STACK_TOP + PAGE_SIZE;
 109 +       if (IS_ENABLED(CONFIG_MIPS_FP_SUPPORT)) {
 110 +               /* Skip the delay slot emulation page */
 111 +               base += PAGE_SIZE;
 112 +       }
 113
 114         if (current->flags & PF_RANDOMIZE) {
 115                 base += get_random_int() & (VDSO_RANDOMIZE_SIZE - 1);
 116 @@ -95,14 +97,16 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
 117         if (down_write_killable(&mm->mmap_sem))
 118                 return -EINTR;
 119
 120 -       /* Map delay slot emulation page */
 121 -       base = mmap_region(NULL, STACK_TOP, PAGE_SIZE,
 122 -                          VM_READ | VM_EXEC |
 123 -                          VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC,
 124 -                          0, NULL);
 125 -       if (IS_ERR_VALUE(base)) {
 126 -               ret = base;
 127 -               goto out;
 128 +       if (IS_ENABLED(CONFIG_MIPS_FP_SUPPORT)) {
 129 +               /* Map delay slot emulation page */
 130 +               base = mmap_region(NULL, STACK_TOP, PAGE_SIZE,
 131 +                               VM_READ | VM_EXEC |
 132 +                               VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC,
 133 +                               0, NULL);
 134 +               if (IS_ERR_VALUE(base)) {
 135 +                       ret = base;
 136 +                       goto out;
 137 +               }
 138         }
 139
 140         /*