bsd-user:Add set_mcontext function for ARM AArch64

The function copies register values from the provided target_mcontext_t
structure to the CPUARMState registers.
Note:FP is unfinished upstream but will be a separate commit coming soon.

Signed-off-by: Stacey Son <sson@FreeBSD.org>
Signed-off-by: Ajeet Singh <itachis@FreeBSD.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20240707191128.10509-8-itachis@FreeBSD.org>
Signed-off-by: Warner Losh <imp@bsdimp.com>

diff --git a/bsd-user/aarch64/signal.c b/bsd-user/aarch64/signal.c
index 43c886e6036ab11f6460c5afbd240549d0dd4fde..13faac8ce60c29d709465f4ea809ed13691ceca0 100644 (file)
--- a/bsd-user/aarch64/signal.c
+++ b/bsd-user/aarch64/signal.c
@@ -95,3 +95,25 @@ abi_long setup_sigframe_arch(CPUARMState *env, abi_ulong frame_addr,
     return 0;
 }
 
+/*
+ * Compare to set_mcontext() in arm64/arm64/machdep.c
+ * Assumes that the memory is locked if frame points to user memory.
+ */
+abi_long set_mcontext(CPUARMState *regs, target_mcontext_t *mcp, int srflag)
+{
+    int err = 0, i;
+    const uint64_t *gr = mcp->mc_gpregs.gp_x;
+
+    for (i = 0; i < 30; i++) {
+        regs->xregs[i] = tswap64(gr[i]);
+    }
+
+    regs->xregs[TARGET_REG_SP] = tswap64(mcp->mc_gpregs.gp_sp);
+    regs->xregs[TARGET_REG_LR] = tswap64(mcp->mc_gpregs.gp_lr);
+    regs->pc = mcp->mc_gpregs.gp_elr;
+    pstate_write(regs, mcp->mc_gpregs.gp_spsr);
+
+    /* XXX FP? */
+
+    return err;
+}