queue-4.19/arcv2-don-t-assume-core-0x54-has-dual-issue.patch

   1 From f13974aca313083542ea0f95d4a7b8abcdb2face Mon Sep 17 00:00:00 2001
   2 From: Vineet Gupta <vgupta@synopsys.com>
   3 Date: Thu, 21 Feb 2019 13:44:49 -0800
   4 Subject: ARCv2: don't assume core 0x54 has dual issue
   5
   6 [ Upstream commit 7b2e932f633bcb7b190fc7031ce6dac75f8c3472 ]
   7
   8 The first release of core4 (0x54) was dual issue only (HS4x).
   9 Newer releases allow hardware to be configured as single issue (HS3x)
  10 or dual issue.
  11
  12 Prevent accessing a HS4x only aux register in HS3x, which otherwise
  13 leads to illegal instruction exceptions
  14
  15 Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
  16 Signed-off-by: Sasha Levin <sashal@kernel.org>
  17 ---
  18  arch/arc/include/asm/arcregs.h |  8 ++++++++
  19  arch/arc/kernel/setup.c        | 26 +++++++++++++++++++++-----
  20  2 files changed, 29 insertions(+), 5 deletions(-)
  21
  22 diff --git a/arch/arc/include/asm/arcregs.h b/arch/arc/include/asm/arcregs.h
  23 index 49bfbd879caa..bdbdaef902eb 100644
  24 --- a/arch/arc/include/asm/arcregs.h
  25 +++ b/arch/arc/include/asm/arcregs.h
  26 @@ -151,6 +151,14 @@ struct bcr_isa_arcv2 {
  27  #endif
  28  };
  29
  30 +struct bcr_uarch_build_arcv2 {
  31 +#ifdef CONFIG_CPU_BIG_ENDIAN
  32 +       unsigned int pad:8, prod:8, maj:8, min:8;
  33 +#else
  34 +       unsigned int min:8, maj:8, prod:8, pad:8;
  35 +#endif
  36 +};
  37 +
  38  struct bcr_mpy {
  39  #ifdef CONFIG_CPU_BIG_ENDIAN
  40         unsigned int pad:8, x1616:8, dsp:4, cycles:2, type:2, ver:8;
  41 diff --git a/arch/arc/kernel/setup.c b/arch/arc/kernel/setup.c
  42 index 62a30e58441c..3320ca2fe20f 100644
  43 --- a/arch/arc/kernel/setup.c
  44 +++ b/arch/arc/kernel/setup.c
  45 @@ -196,13 +196,29 @@ static void read_arc_build_cfg_regs(void)
  46                 cpu->bpu.num_pred = 2048 << bpu.pte;
  47
  48                 if (cpu->core.family >= 0x54) {
  49 -                       unsigned int exec_ctrl;
  50
  51 -                       READ_BCR(AUX_EXEC_CTRL, exec_ctrl);
  52 -                       cpu->extn.dual_enb = !(exec_ctrl & 1);
  53 +                       struct bcr_uarch_build_arcv2 uarch;
  54
  55 -                       /* dual issue always present for this core */
  56 -                       cpu->extn.dual = 1;
  57 +                       /*
  58 +                        * The first 0x54 core (uarch maj:min 0:1 or 0:2) was
  59 +                        * dual issue only (HS4x). But next uarch rev (1:0)
  60 +                        * allows it be configured for single issue (HS3x)
  61 +                        * Ensure we fiddle with dual issue only on HS4x
  62 +                        */
  63 +                       READ_BCR(ARC_REG_MICRO_ARCH_BCR, uarch);
  64 +
  65 +                       if (uarch.prod == 4) {
  66 +                               unsigned int exec_ctrl;
  67 +
  68 +                               /* dual issue hardware always present */
  69 +                               cpu->extn.dual = 1;
  70 +
  71 +                               READ_BCR(AUX_EXEC_CTRL, exec_ctrl);
  72 +
  73 +                               /* dual issue hardware enabled ? */
  74 +                               cpu->extn.dual_enb = !(exec_ctrl & 1);
  75 +
  76 +                       }
  77                 }
  78         }
  79
  80 --
  81 2.19.1
  82