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Diffstat (limited to 'target/ppc/mmu-radix64.c')
-rw-r--r--target/ppc/mmu-radix64.c14
1 files changed, 14 insertions, 0 deletions
diff --git a/target/ppc/mmu-radix64.c b/target/ppc/mmu-radix64.c
index 1d3d9e1..461eda4 100644
--- a/target/ppc/mmu-radix64.c
+++ b/target/ppc/mmu-radix64.c
@@ -571,6 +571,20 @@ static int ppc_radix64_process_scoped_xlate(PowerPCCPU *cpu,
prtbe0 = ldq_phys(cs->as, h_raddr);
}
+ /*
+ * Some Linux uses a zero process table entry in PID!=0 for kernel context
+ * without userspace in order to fault on NULL dereference, because using
+ * PIDR=0 for the kernel causes the Q0 page table to be used to translate
+ * Q3 as well. Check for that case here to avoid the invalid configuration
+ * message.
+ */
+ if (unlikely(!prtbe0)) {
+ if (guest_visible) {
+ ppc_radix64_raise_si(cpu, access_type, eaddr, DSISR_R_BADCONFIG);
+ }
+ return 1;
+ }
+
/* Walk Radix Tree from Process Table Entry to Convert EA to RA */
*g_page_size = PRTBE_R_GET_RTS(prtbe0);
base_addr = prtbe0 & PRTBE_R_RPDB;