[PATCH v3 04/40] bsd-user/arm/signal.c: get_mcontext should zero vfp data

[Warner Losh]

FreeBSD's get_mcontext doesn't return any vfp data. Instead, it zeros
out the vfp feilds (and all the spare fields). Impelement this
behavior. We're still missing the sysarch(ARM_GET_VFPCONTEXT) syscall,
though.

Signed-off-by: Warner Losh <imp@bsdimp.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
---
 bsd-user/arm/signal.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/bsd-user/arm/signal.c b/bsd-user/arm/signal.c
index 9026343b478..2b1dd745d13 100644
--- a/bsd-user/arm/signal.c
+++ b/bsd-user/arm/signal.c
@@ -109,6 +109,15 @@ 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]);
 
+    /*
+     * FreeBSD's get_mcontext doesn't save VFP info, but sets the pointer and
+     * size to zero.  Applications that need the VFP state use
+     * sysarch(ARM_GET_VFPSTATE) and are expected to adjust mcontext after 
that.
+     */
+    mcp->mc_vfp_size = 0;
+    mcp->mc_vfp_ptr = 0;
+    memset(&mcp->mc_spare, 0, sizeof(mcp->mc_spare));
+
     return 0;
 }
 
-- 
2.33.1