[PULL 34/37] bsd-user/arm/signal.c: arm set_mcontext

[Warner Losh <imp@bsdimp.com>]

Move the machine context to the CPU state.

Signed-off-by: Stacey Son <sson@FreeBSD.org>
Signed-off-by: Kyle Evans <kevans@FreeBSD.org>
Signed-off-by: Warner Losh <imp@bsdimp.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
---
 bsd-user/arm/signal.c | 76 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 76 insertions(+)

diff --git a/bsd-user/arm/signal.c b/bsd-user/arm/signal.c
index 93c9bfc0d37..fb6228db6cf 100644
--- a/bsd-user/arm/signal.c
+++ b/bsd-user/arm/signal.c
@@ -109,3 +109,79 @@ abi_long get_mcontext(CPUARMState *env, target_mcontext_t *mcp, int flags)
     }
     return err;
 }
+
+/* Compare to arm/arm/exec_machdep.c set_mcontext() */
+abi_long set_mcontext(CPUARMState *env, target_mcontext_t *mcp, int srflag)
+{
+    int err = 0;
+    const uint32_t *gr = mcp->__gregs;
+    uint32_t cpsr, ccpsr = cpsr_read(env);
+    uint32_t fpscr, mask;
+
+    cpsr = tswap32(gr[TARGET_REG_CPSR]);
+    /*
+     * Only allow certain bits to change, reject attempted changes to non-user
+     * bits. In addition, make sure we're headed for user mode and none of the
+     * interrupt bits are set.
+     */
+    if ((ccpsr & ~CPSR_USER) != (cpsr & ~CPSR_USER)) {
+        return -TARGET_EINVAL;
+    }
+    if ((cpsr & CPSR_M) != ARM_CPU_MODE_USR ||
+        (cpsr & (CPSR_I | CPSR_F)) != 0) {
+        return -TARGET_EINVAL;
+    }
+
+    /*
+     * The movs pc,lr instruction that implements the return to userland masks
+     * these bits out.
+     */
+    mask = cpsr & CPSR_T ? 0x1 : 0x3;
+
+    /*
+     * Make sure that we either have no vfp, or it's the correct size.
+     * FreeBSD just ignores it, though, so maybe we'll need to adjust
+     * things below instead.
+     */
+    if (mcp->mc_vfp_size != 0 && mcp->mc_vfp_size != sizeof(target_mcontext_vfp_t)) {
+        return -TARGET_EINVAL;
+    }
+
+    env->regs[0] = tswap32(gr[TARGET_REG_R0]);
+    env->regs[1] = tswap32(gr[TARGET_REG_R1]);
+    env->regs[2] = tswap32(gr[TARGET_REG_R2]);
+    env->regs[3] = tswap32(gr[TARGET_REG_R3]);
+    env->regs[4] = tswap32(gr[TARGET_REG_R4]);
+    env->regs[5] = tswap32(gr[TARGET_REG_R5]);
+    env->regs[6] = tswap32(gr[TARGET_REG_R6]);
+    env->regs[7] = tswap32(gr[TARGET_REG_R7]);
+    env->regs[8] = tswap32(gr[TARGET_REG_R8]);
+    env->regs[9] = tswap32(gr[TARGET_REG_R9]);
+    env->regs[10] = tswap32(gr[TARGET_REG_R10]);
+    env->regs[11] = tswap32(gr[TARGET_REG_R11]);
+    env->regs[12] = tswap32(gr[TARGET_REG_R12]);
+
+    env->regs[13] = tswap32(gr[TARGET_REG_SP]);
+    env->regs[14] = tswap32(gr[TARGET_REG_LR]);
+    env->regs[15] = tswap32(gr[TARGET_REG_PC] & ~mask);
+    if (mcp->mc_vfp_size != 0 && mcp->mc_vfp_ptr != 0) {
+        /* see set_vfpcontext in sys/arm/arm/exec_machdep.c */
+        target_mcontext_vfp_t *vfp;
+
+        vfp = lock_user(VERIFY_READ, mcp->mc_vfp_ptr, sizeof(*vfp), 1);
+        for (int i = 0; i < 32; i++) {
+            __get_user(*aa32_vfp_dreg(env, i), &vfp->mcv_reg[i]);
+        }
+        __get_user(fpscr, &vfp->mcv_fpscr);
+        vfp_set_fpscr(env, fpscr);
+        unlock_user(vfp, mcp->mc_vfp_ptr, sizeof(target_ucontext_t));
+
+        /*
+         * linux-user sets fpexc, fpinst and fpinst2, but these aren't in
+         * FreeBSD's mcontext, what to do?
+         */
+    }
+    cpsr_write(env, cpsr, CPSR_USER | CPSR_EXEC, CPSRWriteByInstr);
+
+    return err;
+}
-- 
2.33.1