target-arm: Widen thread-local register state fields to 64 bits

The common pattern for system registers in a 64-bit capable ARM
CPU is that when in AArch32 the cp15 register is a view of the
bottom 32 bits of the 64-bit AArch64 system register; writes in
AArch32 leave the top half unchanged. The most natural way to
model this is to have the state field in the CPU struct be a
64 bit value, and simply have the AArch32 TCG code operate on
a pointer to its lower half.

For aarch64-linux-user the only registers we need to share like
this are the thread-local-storage ones. Widen their fields to
64 bits and provide the 64 bit reginfo struct to make them
visible in AArch64 state. Note that minor cleanup of the AArch64
system register encoding space means We can share the TPIDR_EL1
reginfo but need split encodings for TPIDR_EL0 and TPIDRRO_EL0.

Since we're touching almost every line in QEMU that uses the
c13_tls* fields in this patch anyway, we take the opportunity
to rename them in line with the standard ARM architectural names
for these registers.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>

3 files changed, 6 insertions, 3 deletions

diff --git a/linux-user/aarch64/target_cpu.h b/linux-user/aarch64/target_cpu.h
index 6f5539b50f..21560ef832 100644
--- a/linux-user/aarch64/target_cpu.h
+++ b/linux-user/aarch64/target_cpu.h
@@ -29,7 +29,10 @@ static inline void cpu_clone_regs(CPUARMState *env, target_ulong newsp)
 
 static inline void cpu_set_tls(CPUARMState *env, target_ulong newtls)
 {
-    env->sr.tpidr_el0 = newtls;
+    /* Note that AArch64 Linux keeps the TLS pointer in TPIDR; this is
+     * different from AArch32 Linux, which uses TPIDRRO.
+     */
+    env->cp15.tpidr_el0 = newtls;
 }
 
 #endif
diff --git a/linux-user/arm/target_cpu.h b/linux-user/arm/target_cpu.h
index ed323c079d..39d65b692b 100644
--- a/linux-user/arm/target_cpu.h
+++ b/linux-user/arm/target_cpu.h
@@ -29,7 +29,7 @@ static inline void cpu_clone_regs(CPUARMState *env, target_ulong newsp)
 
 static inline void cpu_set_tls(CPUARMState *env, target_ulong newtls)
 {
-    env->cp15.c13_tls2 = newtls;
+    env->cp15.tpidrro_el0 = newtls;
 }
 
 #endif
diff --git a/linux-user/main.c b/linux-user/main.c
index 54f71fe8f6..c0df8b5cd4 100644
--- a/linux-user/main.c
+++ b/linux-user/main.c
@@ -566,7 +566,7 @@ do_kernel_trap(CPUARMState *env)
         end_exclusive();
         break;
     case 0xffff0fe0: /* __kernel_get_tls */
-        env->regs[0] = env->cp15.c13_tls2;
+        env->regs[0] = env->cp15.tpidrro_el0;
         break;
     case 0xffff0f60: /* __kernel_cmpxchg64 */
         arm_kernel_cmpxchg64_helper(env);