linux-user: Introduce cpu_clone_regs_parent

We will need a target-specific hook for adjusting registers
in the parent during clone.  Add an empty inline function for
each target, and invoke it from the proper places.

Reviewed-by: Laurent Vivier <laurent@vivier.eu>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-Id: <20191106113318.10226-11-richard.henderson@linaro.org>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>

linux-user/aarch64/target_cpu.h

@@ -28,6 +28,10 @@ static inline void cpu_clone_regs_child(CPUARMState *env, target_ulong newsp,
     env->xregs[0] = 0;
 }
 
+static inline void cpu_clone_regs_parent(CPUARMState *env, unsigned flags)
+{
+}
+
 static inline void cpu_set_tls(CPUARMState *env, target_ulong newtls)
 {
     /* Note that AArch64 Linux keeps the TLS pointer in TPIDR; this is

linux-user/alpha/target_cpu.h

@@ -29,6 +29,10 @@ static inline void cpu_clone_regs_child(CPUAlphaState *env, target_ulong newsp,
     env->ir[IR_A3] = 0;
 }
 
+static inline void cpu_clone_regs_parent(CPUAlphaState *env, unsigned flags)
+{
+}
+
 static inline void cpu_set_tls(CPUAlphaState *env, target_ulong newtls)
 {
     env->unique = newtls;

linux-user/arm/target_cpu.h

@@ -50,6 +50,10 @@ static inline void cpu_clone_regs_child(CPUARMState *env, target_ulong newsp,
     env->regs[0] = 0;
 }
 
+static inline void cpu_clone_regs_parent(CPUARMState *env, unsigned flags)
+{
+}
+
 static inline void cpu_set_tls(CPUARMState *env, target_ulong newtls)
 {
     if (access_secure_reg(env)) {

linux-user/cris/target_cpu.h

@@ -29,6 +29,10 @@ static inline void cpu_clone_regs_child(CPUCRISState *env, target_ulong newsp,
     env->regs[10] = 0;
 }
 
+static inline void cpu_clone_regs_parent(CPUCRISState *env, unsigned flags)
+{
+}
+
 static inline void cpu_set_tls(CPUCRISState *env, target_ulong newtls)
 {
     env->pregs[PR_PID] = (env->pregs[PR_PID] & 0xff) | newtls;

linux-user/hppa/target_cpu.h

@@ -32,6 +32,10 @@ static inline void cpu_clone_regs_child(CPUHPPAState *env, target_ulong newsp,
     env->iaoq_b = env->gr[31] + 4;
 }
 
+static inline void cpu_clone_regs_parent(CPUHPPAState *env, unsigned flags)
+{
+}
+
 static inline void cpu_set_tls(CPUHPPAState *env, target_ulong newtls)
 {
     env->cr[27] = newtls;

linux-user/i386/target_cpu.h

@@ -29,6 +29,10 @@ static inline void cpu_clone_regs_child(CPUX86State *env, target_ulong newsp,
     env->regs[R_EAX] = 0;
 }
 
+static inline void cpu_clone_regs_parent(CPUX86State *env, unsigned flags)
+{
+}
+
 #if defined(TARGET_ABI32)
 abi_long do_set_thread_area(CPUX86State *env, abi_ulong ptr);
 

linux-user/m68k/target_cpu.h

@@ -30,6 +30,10 @@ static inline void cpu_clone_regs_child(CPUM68KState *env, target_ulong newsp,
     env->dregs[0] = 0;
 }
 
+static inline void cpu_clone_regs_parent(CPUM68KState *env, unsigned flags)
+{
+}
+
 static inline void cpu_set_tls(CPUM68KState *env, target_ulong newtls)
 {
     CPUState *cs = env_cpu(env);

linux-user/microblaze/target_cpu.h

@@ -28,6 +28,10 @@ static inline void cpu_clone_regs_child(CPUMBState *env, target_ulong newsp,
     env->regs[3] = 0;
 }
 
+static inline void cpu_clone_regs_parent(CPUMBState *env, unsigned flags)
+{
+}
+
 static inline void cpu_set_tls(CPUMBState *env, target_ulong newtls)
 {
     env->regs[21] = newtls;

linux-user/mips/target_cpu.h

@@ -29,6 +29,10 @@ static inline void cpu_clone_regs_child(CPUMIPSState *env, target_ulong newsp,
     env->active_tc.gpr[2] = 0;
 }
 
+static inline void cpu_clone_regs_parent(CPUMIPSState *env, unsigned flags)
+{
+}
+
 static inline void cpu_set_tls(CPUMIPSState *env, target_ulong newtls)
 {
     env->active_tc.CP0_UserLocal = newtls;

linux-user/nios2/target_cpu.h

@@ -29,6 +29,10 @@ static inline void cpu_clone_regs_child(CPUNios2State *env, target_ulong newsp,
     env->regs[R_RET0] = 0;
 }
 
+static inline void cpu_clone_regs_parent(CPUNios2State *env, unsigned flags)
+{
+}
+
 static inline void cpu_set_tls(CPUNios2State *env, target_ulong newtls)
 {
     /*

linux-user/openrisc/target_cpu.h

@@ -30,6 +30,10 @@ static inline void cpu_clone_regs_child(CPUOpenRISCState *env,
     cpu_set_gpr(env, 11, 0);
 }
 
+static inline void cpu_clone_regs_parent(CPUOpenRISCState *env, unsigned flags)
+{
+}
+
 static inline void cpu_set_tls(CPUOpenRISCState *env, target_ulong newtls)
 {
     cpu_set_gpr(env, 10, newtls);

linux-user/ppc/target_cpu.h

@@ -28,6 +28,10 @@ static inline void cpu_clone_regs_child(CPUPPCState *env, target_ulong newsp,
     env->gpr[3] = 0;
 }
 
+static inline void cpu_clone_regs_parent(CPUPPCState *env, unsigned flags)
+{
+}
+
 static inline void cpu_set_tls(CPUPPCState *env, target_ulong newtls)
 {
 #if defined(TARGET_PPC64)

linux-user/riscv/target_cpu.h

@@ -11,6 +11,10 @@ static inline void cpu_clone_regs_child(CPURISCVState *env, target_ulong newsp,
     env->gpr[xA0] = 0;
 }
 
+static inline void cpu_clone_regs_parent(CPURISCVState *env, unsigned flags)
+{
+}
+
 static inline void cpu_set_tls(CPURISCVState *env, target_ulong newtls)
 {
     env->gpr[xTP] = newtls;

linux-user/s390x/target_cpu.h

@@ -28,6 +28,10 @@ static inline void cpu_clone_regs_child(CPUS390XState *env, target_ulong newsp,
     env->regs[2] = 0;
 }
 
+static inline void cpu_clone_regs_parent(CPUS390XState *env, unsigned flags)
+{
+}
+
 static inline void cpu_set_tls(CPUS390XState *env, target_ulong newtls)
 {
     env->aregs[0] = newtls >> 32;

linux-user/sh4/target_cpu.h

@@ -28,6 +28,10 @@ static inline void cpu_clone_regs_child(CPUSH4State *env, target_ulong newsp,
     env->gregs[0] = 0;
 }
 
+static inline void cpu_clone_regs_parent(CPUSH4State *env, unsigned flags)
+{
+}
+
 static inline void cpu_set_tls(CPUSH4State *env, target_ulong newtls)
 {
   env->gbr = newtls;

linux-user/sparc/target_cpu.h

@@ -37,6 +37,10 @@ static inline void cpu_clone_regs_child(CPUSPARCState *env, target_ulong newsp,
 #endif
 }
 
+static inline void cpu_clone_regs_parent(CPUSPARCState *env, unsigned flags)
+{
+}
+
 static inline void cpu_set_tls(CPUSPARCState *env, target_ulong newtls)
 {
     env->gregs[7] = newtls;

linux-user/syscall.c

@@ -5821,6 +5821,7 @@ static int do_fork(CPUArchState *env, unsigned int flags, abi_ulong newsp,
         new_env = cpu_copy(env);
         /* Init regs that differ from the parent.  */
         cpu_clone_regs_child(new_env, newsp, flags);
+        cpu_clone_regs_parent(env, flags);
         new_cpu = env_cpu(new_env);
         new_cpu->opaque = ts;
         ts->bprm = parent_ts->bprm;
@@ -5917,6 +5918,7 @@ static int do_fork(CPUArchState *env, unsigned int flags, abi_ulong newsp,
             if (flags & CLONE_CHILD_CLEARTID)
                 ts->child_tidptr = child_tidptr;
         } else {
+            cpu_clone_regs_parent(env, flags);
             fork_end(0);
         }
     }

linux-user/tilegx/target_cpu.h

@@ -28,6 +28,10 @@ static inline void cpu_clone_regs_child(CPUTLGState *env, target_ulong newsp,
     env->regs[TILEGX_R_RE] = 0;
 }
 
+static inline void cpu_clone_regs_parent(CPUTLGState *env, unsigned flags)
+{
+}
+
 static inline void cpu_set_tls(CPUTLGState *env, target_ulong newtls)
 {
     env->regs[TILEGX_R_TP] = newtls;

linux-user/xtensa/target_cpu.h

@@ -16,6 +16,10 @@ static inline void cpu_clone_regs_child(CPUXtensaState *env,
     env->regs[2] = 0;
 }
 
+static inline void cpu_clone_regs_parent(CPUXtensaState *env, unsigned flags)
+{
+}
+
 static inline void cpu_set_tls(CPUXtensaState *env, target_ulong newtls)
 {
     env->uregs[THREADPTR] = newtls;