[PATCH v3 03/40] bsd-user/arm/signal.c: Implement setup_sigframe_arch for arm

[Warner Losh <imp@bsdimp.com>]

Fix the broken context setting for arm. FreeBSD's get_mcontext does not
fill in the vfp info. It's filled in in sigframe(). This corresponds to
the new setup_sigframe_arch which fills in mcontext, then adjusts it to
point to the vfp context in the sigframe and fills in that context as
well. Add pointer to where this code is done.

Signed-off-by: Warner Losh <imp@bsdimp.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
---
 bsd-user/arm/signal.c | 50 ++++++++++++++++++++++++++++---------------
 1 file changed, 33 insertions(+), 17 deletions(-)

diff --git a/bsd-user/arm/signal.c b/bsd-user/arm/signal.c
index 1478f008d13..9026343b478 100644
--- a/bsd-user/arm/signal.c
+++ b/bsd-user/arm/signal.c
@@ -59,19 +59,31 @@ abi_long set_sigtramp_args(CPUARMState *env, int sig,
     return 0;
 }
 
+static abi_long get_vfpcontext(CPUARMState *env, abi_ulong frame_addr,
+                               struct target_sigframe *frame)
+{
+    /* see sendsig and get_vfpcontext in sys/arm/arm/exec_machdep.c */
+    target_mcontext_vfp_t *vfp = &frame->sf_vfp;
+    target_mcontext_t *mcp = &frame->sf_uc.uc_mcontext;
+
+    /* Assumes that mcp and vfp are locked */
+    for (int i = 0; i < 32; i++) {
+        vfp->mcv_reg[i] = tswap64(*aa32_vfp_dreg(env, i));
+    }
+    vfp->mcv_fpscr = tswap32(vfp_get_fpscr(env));
+    mcp->mc_vfp_size = tswap32(sizeof(*vfp));
+    mcp->mc_vfp_ptr = tswap32(frame_addr + ((uintptr_t)vfp - (uintptr_t)frame));
+    return 0;
+}
+
 /*
- * Compare to arm/arm/machdep.c get_mcontext()
+ * Compare to arm/arm/exec_machdep.c get_mcontext()
  * Assumes that the memory is locked if mcp points to user memory.
  */
 abi_long get_mcontext(CPUARMState *env, target_mcontext_t *mcp, int flags)
 {
-    int err = 0;
     uint32_t *gr = mcp->__gregs;
 
-    if (mcp->mc_vfp_size != 0 && mcp->mc_vfp_size != sizeof(target_mcontext_vfp_t)) {
-        return -TARGET_EINVAL;
-    }
-
     gr[TARGET_REG_CPSR] = tswap32(cpsr_read(env));
     if (flags & TARGET_MC_GET_CLEAR_RET) {
         gr[TARGET_REG_R0] = 0;
@@ -97,17 +109,21 @@ abi_long get_mcontext(CPUARMState *env, target_mcontext_t *mcp, int flags)
     gr[TARGET_REG_LR] = tswap32(env->regs[14]);
     gr[TARGET_REG_PC] = tswap32(env->regs[15]);
 
-    if (mcp->mc_vfp_size != 0 && mcp->mc_vfp_ptr != 0) {
-        /* see get_vfpcontext in sys/arm/arm/exec_machdep.c */
-        target_mcontext_vfp_t *vfp;
-        vfp = lock_user(VERIFY_WRITE, mcp->mc_vfp_ptr, sizeof(*vfp), 0);
-        for (int i = 0; i < 32; i++) {
-            vfp->mcv_reg[i] = tswap64(*aa32_vfp_dreg(env, i));
-        }
-        vfp->mcv_fpscr = tswap32(vfp_get_fpscr(env));
-        unlock_user(vfp, mcp->mc_vfp_ptr, sizeof(*vfp));
-    }
-    return err;
+    return 0;
+}
+
+/*
+ * Compare to arm/arm/exec_machdep.c sendsig()
+ * Assumes that the memory is locked if frame points to user memory.
+ */
+abi_long setup_sigframe_arch(CPUARMState *env, abi_ulong frame_addr,
+                             struct target_sigframe *frame, int flags)
+{
+    target_mcontext_t *mcp = &frame->sf_uc.uc_mcontext;
+
+    get_mcontext(env, mcp, flags);
+    get_vfpcontext(env, frame_addr, frame);
+    return 0;
 }
 
 /* Compare to arm/arm/exec_machdep.c set_mcontext() */
-- 
2.33.1