[Qemu-devel] [PATCH v4 3/4] target-ppc: ppc can be either endian

[Greg Kurz <gkurz@linux.vnet.ibm.com>]

POWER7, POWER7+ and POWER8 families use the ILE bit of the LPCR
special purpose register to decide the endianness to use when
entering interrupt handlers. When running a Linux guest, this
provides a hint on the endianness used by the kernel. And when
it comes to dumping a guest, the information is needed to write
ELF headers using the kernel endianness.

Suggested-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Greg Kurz <gkurz@linux.vnet.ibm.com>
---

Changes since v3:
 updated description

 target-ppc/cpu-qom.h        |    1 +
 target-ppc/translate_init.c |   16 ++++++++++++++++
 2 files changed, 17 insertions(+)

diff --git a/target-ppc/cpu-qom.h b/target-ppc/cpu-qom.h
index 47dc8e6..fdce638 100644
--- a/target-ppc/cpu-qom.h
+++ b/target-ppc/cpu-qom.h
@@ -76,6 +76,7 @@ typedef struct PowerPCCPUClass {
     int (*handle_mmu_fault)(PowerPCCPU *cpu, target_ulong eaddr, int rwx,
                             int mmu_idx);
 #endif
+    bool (*interrupts_big_endian)(PowerPCCPU *cpu);
 } PowerPCCPUClass;
 
 /**
diff --git a/target-ppc/translate_init.c b/target-ppc/translate_init.c
index 7f53c33..a27e5a7 100644
--- a/target-ppc/translate_init.c
+++ b/target-ppc/translate_init.c
@@ -3102,6 +3102,18 @@ static int check_pow_hid0_74xx (CPUPPCState *env)
     return 0;
 }
 
+static bool ppc_cpu_interrupts_big_endian_always(PowerPCCPU *cpu)
+{
+    return true;
+}
+
+#ifdef TARGET_PPC64
+static bool ppc_cpu_interrupts_big_endian_lpcr(PowerPCCPU *cpu)
+{
+    return !(cpu->env.spr[SPR_LPCR] & LPCR_ILE);
+}
+#endif
+
 /*****************************************************************************/
 /* PowerPC implementations definitions                                       */
 
@@ -7089,6 +7101,7 @@ POWERPC_FAMILY(POWER7)(ObjectClass *oc, void *data)
                  POWERPC_FLAG_VSX;
     pcc->l1_dcache_size = 0x8000;
     pcc->l1_icache_size = 0x8000;
+    pcc->interrupts_big_endian = ppc_cpu_interrupts_big_endian_lpcr;
 }
 
 POWERPC_FAMILY(POWER7P)(ObjectClass *oc, void *data)
@@ -7132,6 +7145,7 @@ POWERPC_FAMILY(POWER7P)(ObjectClass *oc, void *data)
                  POWERPC_FLAG_VSX;
     pcc->l1_dcache_size = 0x8000;
     pcc->l1_icache_size = 0x8000;
+    pcc->interrupts_big_endian = ppc_cpu_interrupts_big_endian_lpcr;
 }
 
 static void init_proc_POWER8(CPUPPCState *env)
@@ -7189,6 +7203,7 @@ POWERPC_FAMILY(POWER8)(ObjectClass *oc, void *data)
                  POWERPC_FLAG_VSX;
     pcc->l1_dcache_size = 0x8000;
     pcc->l1_icache_size = 0x8000;
+    pcc->interrupts_big_endian = ppc_cpu_interrupts_big_endian_lpcr;
 }
 #endif /* defined (TARGET_PPC64) */
 
@@ -8511,6 +8526,7 @@ static void ppc_cpu_class_init(ObjectClass *oc, void *data)
     pcc->parent_realize = dc->realize;
     pcc->pvr = CPU_POWERPC_DEFAULT_MASK;
     pcc->pvr_mask = CPU_POWERPC_DEFAULT_MASK;
+    pcc->interrupts_big_endian = ppc_cpu_interrupts_big_endian_always;
     dc->realize = ppc_cpu_realizefn;
     dc->unrealize = ppc_cpu_unrealizefn;