target-mips: Implement FCR31's R/W bitmask and related functionalities

This patch implements read and write access rules for Mips floating
point control and status register (FCR31). The change can be divided
into following parts:

- Add fields that will keep FCR31's R/W bitmask in procesor
  definitions and processor float_status structure.

- Add appropriate value for FCR31's R/W bitmask for each supported
  processor.

- Add function for setting snan_bit_is_one, and integrate it in
  appropriate places.

- Modify handling of CTC1 (case 31) instruction to use FCR31's R/W
  bitmask.

- Modify handling user mode executables for Mips, in relation to the
  bit EF_MIPS_NAN2008 from ELF header, that is in turn related to
  reading and writing to FCR31.

- Modify gdb behavior in relation to FCR31.

Signed-off-by: Thomas Schwinge <thomas@codesourcery.com>
Signed-off-by: Maciej W. Rozycki <macro@codesourcery.com>
Signed-off-by: Aleksandar Markovic <aleksandar.markovic@imgtec.com>
Reviewed-by: Leon Alrae <leon.alrae@imgtec.com>
Signed-off-by: Leon Alrae <leon.alrae@imgtec.com>

1 files changed, 26 insertions, 0 deletions

diff --git a/target-mips/translate_init.c b/target-mips/translate_init.c
index a37d8bb60c..b10284cc5d 100644
--- a/target-mips/translate_init.c
+++ b/target-mips/translate_init.c
@@ -84,6 +84,7 @@ struct mips_def_t {
     int32_t CP0_TCStatus_rw_bitmask;
     int32_t CP0_SRSCtl;
     int32_t CP1_fcr0;
+    int32_t CP1_fcr31_rw_bitmask;
     int32_t CP1_fcr31;
     int32_t MSAIR;
     int32_t SEGBITS;
@@ -273,6 +274,8 @@ static const mips_def_t mips_defs[] =
         .CP0_Status_rw_bitmask = 0x3678FF1F,
         .CP1_fcr0 = (1 << FCR0_F64) | (1 << FCR0_L) | (1 << FCR0_W) |
                     (1 << FCR0_D) | (1 << FCR0_S) | (0x93 << FCR0_PRID),
+        .CP1_fcr31 = 0,
+        .CP1_fcr31_rw_bitmask = 0xFF83FFFF,
         .SEGBITS = 32,
         .PABITS = 32,
         .insn_flags = CPU_MIPS32R2 | ASE_MIPS16,
@@ -303,6 +306,8 @@ static const mips_def_t mips_defs[] =
                     (0xff << CP0TCSt_TASID),
         .CP1_fcr0 = (1 << FCR0_F64) | (1 << FCR0_L) | (1 << FCR0_W) |
                     (1 << FCR0_D) | (1 << FCR0_S) | (0x95 << FCR0_PRID),
+        .CP1_fcr31 = 0,
+        .CP1_fcr31_rw_bitmask = 0xFF83FFFF,
         .CP0_SRSCtl = (0xf << CP0SRSCtl_HSS),
         .CP0_SRSConf0_rw_bitmask = 0x3fffffff,
         .CP0_SRSConf0 = (1U << CP0SRSC0_M) | (0x3fe << CP0SRSC0_SRS3) |
@@ -343,6 +348,8 @@ static const mips_def_t mips_defs[] =
         .CP0_Status_rw_bitmask = 0x3778FF1F,
         .CP1_fcr0 = (1 << FCR0_F64) | (1 << FCR0_L) | (1 << FCR0_W) |
                     (1 << FCR0_D) | (1 << FCR0_S) | (0x93 << FCR0_PRID),
+        .CP1_fcr31 = 0,
+        .CP1_fcr31_rw_bitmask = 0xFF83FFFF,
         .SEGBITS = 32,
         .PABITS = 32,
         .insn_flags = CPU_MIPS32R2 | ASE_MIPS16 | ASE_DSP | ASE_DSPR2,
@@ -427,6 +434,7 @@ static const mips_def_t mips_defs[] =
                     (1 << FCR0_F64) | (1 << FCR0_L) | (1 << FCR0_W) |
                     (1 << FCR0_D) | (1 << FCR0_S) | (0x03 << FCR0_PRID),
         .CP1_fcr31 = (1 << FCR31_ABS2008) | (1 << FCR31_NAN2008),
+        .CP1_fcr31_rw_bitmask = 0xFF83FFFF,
         .SEGBITS = 32,
         .PABITS = 40,
         .insn_flags = CPU_MIPS32R5 | ASE_MSA,
@@ -465,6 +473,7 @@ static const mips_def_t mips_defs[] =
                     (1 << FCR0_L) | (1 << FCR0_W) | (1 << FCR0_D) |
                     (1 << FCR0_S) | (0x00 << FCR0_PRID) | (0x0 << FCR0_REV),
         .CP1_fcr31 = (1 << FCR31_ABS2008) | (1 << FCR31_NAN2008),
+        .CP1_fcr31_rw_bitmask = 0x0103FFFF,
         .SEGBITS = 32,
         .PABITS = 32,
         .insn_flags = CPU_MIPS32R6 | ASE_MICROMIPS,
@@ -485,6 +494,8 @@ static const mips_def_t mips_defs[] =
         .CP0_Status_rw_bitmask = 0x3678FFFF,
         /* The R4000 has a full 64bit FPU but doesn't use the fcr0 bits. */
         .CP1_fcr0 = (0x5 << FCR0_PRID) | (0x0 << FCR0_REV),
+        .CP1_fcr31 = 0,
+        .CP1_fcr31_rw_bitmask = 0x0183FFFF,
         .SEGBITS = 40,
         .PABITS = 36,
         .insn_flags = CPU_MIPS3,
@@ -503,6 +514,8 @@ static const mips_def_t mips_defs[] =
         .CP0_Status_rw_bitmask = 0x3678FFFF,
         /* The VR5432 has a full 64bit FPU but doesn't use the fcr0 bits. */
         .CP1_fcr0 = (0x54 << FCR0_PRID) | (0x0 << FCR0_REV),
+        .CP1_fcr31 = 0,
+        .CP1_fcr31_rw_bitmask = 0xFF83FFFF,
         .SEGBITS = 40,
         .PABITS = 32,
         .insn_flags = CPU_VR54XX,
@@ -548,6 +561,8 @@ static const mips_def_t mips_defs[] =
         /* The 5Kf has F64 / L / W but doesn't use the fcr0 bits. */
         .CP1_fcr0 = (1 << FCR0_D) | (1 << FCR0_S) |
                     (0x81 << FCR0_PRID) | (0x0 << FCR0_REV),
+        .CP1_fcr31 = 0,
+        .CP1_fcr31_rw_bitmask = 0xFF83FFFF,
         .SEGBITS = 42,
         .PABITS = 36,
         .insn_flags = CPU_MIPS64,
@@ -575,6 +590,8 @@ static const mips_def_t mips_defs[] =
         .CP1_fcr0 = (1 << FCR0_3D) | (1 << FCR0_PS) |
                     (1 << FCR0_D) | (1 << FCR0_S) |
                     (0x82 << FCR0_PRID) | (0x0 << FCR0_REV),
+        .CP1_fcr31 = 0,
+        .CP1_fcr31_rw_bitmask = 0xFF83FFFF,
         .SEGBITS = 40,
         .PABITS = 36,
         .insn_flags = CPU_MIPS64 | ASE_MIPS3D,
@@ -601,6 +618,8 @@ static const mips_def_t mips_defs[] =
         .CP1_fcr0 = (1 << FCR0_F64) | (1 << FCR0_3D) | (1 << FCR0_PS) |
                     (1 << FCR0_L) | (1 << FCR0_W) | (1 << FCR0_D) |
                     (1 << FCR0_S) | (0x00 << FCR0_PRID) | (0x0 << FCR0_REV),
+        .CP1_fcr31 = 0,
+        .CP1_fcr31_rw_bitmask = 0xFF83FFFF,
         .SEGBITS = 42,
         .PABITS = 36,
         .insn_flags = CPU_MIPS64R2 | ASE_MIPS3D,
@@ -686,6 +705,7 @@ static const mips_def_t mips_defs[] =
                     (1 << FCR0_L) | (1 << FCR0_W) | (1 << FCR0_D) |
                     (1 << FCR0_S) | (0x00 << FCR0_PRID) | (0x0 << FCR0_REV),
         .CP1_fcr31 = (1 << FCR31_ABS2008) | (1 << FCR31_NAN2008),
+        .CP1_fcr31_rw_bitmask = 0x0103FFFF,
         .SEGBITS = 48,
         .PABITS = 48,
         .insn_flags = CPU_MIPS64R6 | ASE_MSA,
@@ -704,6 +724,8 @@ static const mips_def_t mips_defs[] =
         .CCRes = 2,
         .CP0_Status_rw_bitmask = 0x35D0FFFF,
         .CP1_fcr0 = (0x5 << FCR0_PRID) | (0x1 << FCR0_REV),
+        .CP1_fcr31 = 0,
+        .CP1_fcr31_rw_bitmask = 0xFF83FFFF,
         .SEGBITS = 40,
         .PABITS = 40,
         .insn_flags = CPU_LOONGSON2E,
@@ -722,6 +744,8 @@ static const mips_def_t mips_defs[] =
         .CCRes = 2,
         .CP0_Status_rw_bitmask = 0xF5D0FF1F,   /* Bits 7:5 not writable.  */
         .CP1_fcr0 = (0x5 << FCR0_PRID) | (0x1 << FCR0_REV),
+        .CP1_fcr31 = 0,
+        .CP1_fcr31_rw_bitmask = 0xFF83FFFF,
         .SEGBITS = 40,
         .PABITS = 40,
         .insn_flags = CPU_LOONGSON2F,
@@ -749,6 +773,8 @@ static const mips_def_t mips_defs[] =
         .CP1_fcr0 = (1 << FCR0_F64) | (1 << FCR0_3D) | (1 << FCR0_PS) |
                     (1 << FCR0_L) | (1 << FCR0_W) | (1 << FCR0_D) |
                     (1 << FCR0_S) | (0x00 << FCR0_PRID) | (0x0 << FCR0_REV),
+        .CP1_fcr31 = 0,
+        .CP1_fcr31_rw_bitmask = 0xFF83FFFF,
         .SEGBITS = 42,
         .PABITS = 36,
         .insn_flags = CPU_MIPS64R2 | ASE_DSP | ASE_DSPR2,