linux-user: Split out do_prctl and subroutines

Since the prctl constants are supposed to be generic, supply
any that are not provided by the host.

Split out subroutines for PR_GET_FP_MODE, PR_SET_FP_MODE,
PR_GET_VL, PR_SET_VL, PR_RESET_KEYS, PR_SET_TAGGED_ADDR_CTRL,
PR_GET_TAGGED_ADDR_CTRL.  Return EINVAL for guests that do
not support these options rather than pass them on to the host.

Reviewed-by: Laurent Vivier <laurent@vivier.eu>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20211227150127.2659293-2-richard.henderson@linaro.org>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>

2 files changed, 88 insertions, 6 deletions

diff --git a/linux-user/mips/target_prctl.h b/linux-user/mips/target_prctl.h
new file mode 100644
index 0000000..e028333
--- /dev/null
+++ b/linux-user/mips/target_prctl.h
@@ -0,0 +1,88 @@
+/*
+ * MIPS specific prctl functions for linux-user
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+#ifndef MIPS_TARGET_PRCTL_H
+#define MIPS_TARGET_PRCTL_H
+
+static abi_long do_prctl_get_fp_mode(CPUArchState *env)
+{
+    abi_long ret = 0;
+
+    if (env->CP0_Status & (1 << CP0St_FR)) {
+        ret |= PR_FP_MODE_FR;
+    }
+    if (env->CP0_Config5 & (1 << CP0C5_FRE)) {
+        ret |= PR_FP_MODE_FRE;
+    }
+    return ret;
+}
+#define do_prctl_get_fp_mode do_prctl_get_fp_mode
+
+static abi_long do_prctl_set_fp_mode(CPUArchState *env, abi_long arg2)
+{
+    bool old_fr = env->CP0_Status & (1 << CP0St_FR);
+    bool old_fre = env->CP0_Config5 & (1 << CP0C5_FRE);
+    bool new_fr = arg2 & PR_FP_MODE_FR;
+    bool new_fre = arg2 & PR_FP_MODE_FRE;
+    const unsigned int known_bits = PR_FP_MODE_FR | PR_FP_MODE_FRE;
+
+    /* If nothing to change, return right away, successfully.  */
+    if (old_fr == new_fr && old_fre == new_fre) {
+        return 0;
+    }
+    /* Check the value is valid */
+    if (arg2 & ~known_bits) {
+        return -TARGET_EOPNOTSUPP;
+    }
+    /* Setting FRE without FR is not supported.  */
+    if (new_fre && !new_fr) {
+        return -TARGET_EOPNOTSUPP;
+    }
+    if (new_fr && !(env->active_fpu.fcr0 & (1 << FCR0_F64))) {
+        /* FR1 is not supported */
+        return -TARGET_EOPNOTSUPP;
+    }
+    if (!new_fr && (env->active_fpu.fcr0 & (1 << FCR0_F64))
+        && !(env->CP0_Status_rw_bitmask & (1 << CP0St_FR))) {
+        /* cannot set FR=0 */
+        return -TARGET_EOPNOTSUPP;
+    }
+    if (new_fre && !(env->active_fpu.fcr0 & (1 << FCR0_FREP))) {
+        /* Cannot set FRE=1 */
+        return -TARGET_EOPNOTSUPP;
+    }
+
+    int i;
+    fpr_t *fpr = env->active_fpu.fpr;
+    for (i = 0; i < 32 ; i += 2) {
+        if (!old_fr && new_fr) {
+            fpr[i].w[!FP_ENDIAN_IDX] = fpr[i + 1].w[FP_ENDIAN_IDX];
+        } else if (old_fr && !new_fr) {
+            fpr[i + 1].w[FP_ENDIAN_IDX] = fpr[i].w[!FP_ENDIAN_IDX];
+        }
+    }
+
+    if (new_fr) {
+        env->CP0_Status |= (1 << CP0St_FR);
+        env->hflags |= MIPS_HFLAG_F64;
+    } else {
+        env->CP0_Status &= ~(1 << CP0St_FR);
+        env->hflags &= ~MIPS_HFLAG_F64;
+    }
+    if (new_fre) {
+        env->CP0_Config5 |= (1 << CP0C5_FRE);
+        if (env->active_fpu.fcr0 & (1 << FCR0_FREP)) {
+            env->hflags |= MIPS_HFLAG_FRE;
+        }
+    } else {
+        env->CP0_Config5 &= ~(1 << CP0C5_FRE);
+        env->hflags &= ~MIPS_HFLAG_FRE;
+    }
+
+    return 0;
+}
+#define do_prctl_set_fp_mode do_prctl_set_fp_mode
+
+#endif /* MIPS_TARGET_PRCTL_H */
diff --git a/linux-user/mips/target_syscall.h b/linux-user/mips/target_syscall.h
index 7a82661..08ead67 100644
--- a/linux-user/mips/target_syscall.h
+++ b/linux-user/mips/target_syscall.h
@@ -35,10 +35,4 @@ static inline abi_ulong target_shmlba(CPUMIPSState *env)
     return 0x40000;
 }
 
-/* MIPS-specific prctl() options */
-#define TARGET_PR_SET_FP_MODE  45
-#define TARGET_PR_GET_FP_MODE  46
-#define TARGET_PR_FP_MODE_FR   (1 << 0)
-#define TARGET_PR_FP_MODE_FRE  (1 << 1)
-
 #endif /* MIPS_TARGET_SYSCALL_H */