target/ppc: Flush TLB on write to PIDR

The PIDR (process id register) is used to store the id of the currently
running process, which is used to select the process table entry used to
perform address translation. This means that when we write to this register
all the translations in the TLB become outdated as they are for a
previously running process. Thus when this register is written to we need
to invalidate the TLB entries to ensure stale entries aren't used to
to perform translation for the new process, which would result in at best
segfaults or alternatively just random memory being accessed.

Signed-off-by: Suraj Jitindar Singh <sjitindarsingh@gmail.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
[dwg: Fixed compile error for 32-bit targets]
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>

1 files changed, 8 insertions, 0 deletions

diff --git a/target/ppc/misc_helper.c b/target/ppc/misc_helper.c
index fa573dd7d2..0e4217821b 100644
--- a/target/ppc/misc_helper.c
+++ b/target/ppc/misc_helper.c
@@ -88,6 +88,14 @@ void helper_store_sdr1(CPUPPCState *env, target_ulong val)
     }
 }
 
+void helper_store_pidr(CPUPPCState *env, target_ulong val)
+{
+    PowerPCCPU *cpu = ppc_env_get_cpu(env);
+
+    env->spr[SPR_BOOKS_PID] = val;
+    tlb_flush(CPU(cpu));
+}
+
 void helper_store_hid0_601(CPUPPCState *env, target_ulong val)
 {
     target_ulong hid0;