[Qemu-devel] [PATCH v2 1/3] linux-user: Support little-endian PPC64 in user mode.

[Doug Kwan <dougkwan@google.com>]

Look at ELF header to determin ABI version on PPC64.  This is required
for executing the first instruction correctly.  Also print correct machine
name in uname() system call.

Signed-off-by: Doug Kwan <dougkwan@google.com>
---
 include/elf.h        |  5 +++++
 linux-user/elfload.c | 17 +++++++++++++++--
 linux-user/uname.c   |  6 ++++++
 3 files changed, 26 insertions(+), 2 deletions(-)

diff --git a/include/elf.h b/include/elf.h
index 1599ab2..f9f1675 100644
--- a/include/elf.h
+++ b/include/elf.h
@@ -561,6 +561,11 @@ typedef struct {
 #define SHF_ALPHA_GPREL		0x10000000
 
 
+/* PowerPC specific definitions.  */
+
+/* Processor specific flags for the ELF header e_flags field.  */
+#define EF_PPC64_ABI		0x3
+
 /* PowerPC relocations defined by the ABIs */
 #define R_PPC_NONE		0
 #define R_PPC_ADDR32		1	/* 32bit absolute address */
diff --git a/linux-user/elfload.c b/linux-user/elfload.c
index 995f999..b96d64a 100644
--- a/linux-user/elfload.c
+++ b/linux-user/elfload.c
@@ -777,12 +777,18 @@ static uint32_t get_elf_hwcap(void)
         NEW_AUX_ENT(AT_IGNOREPPC, AT_IGNOREPPC);        \
     } while (0)
 
+static inline uint32_t get_ppc64_abi(struct image_info *infop);
+
 static inline void init_thread(struct target_pt_regs *_regs, struct image_info *infop)
 {
     _regs->gpr[1] = infop->start_stack;
 #if defined(TARGET_PPC64) && !defined(TARGET_ABI32)
-    _regs->gpr[2] = ldq_raw(infop->entry + 8) + infop->load_bias;
-    infop->entry = ldq_raw(infop->entry) + infop->load_bias;
+    if (get_ppc64_abi(infop) < 2) {
+      _regs->gpr[2] = ldq_raw(infop->entry + 8) + infop->load_bias;
+      infop->entry = ldq_raw(infop->entry) + infop->load_bias;
+    } else {
+      _regs->gpr[12] = infop->entry;  /* r12 set to global entry address */
+    }
 #endif
     _regs->nip = infop->entry;
 }
@@ -1152,6 +1158,13 @@ static inline void init_thread(struct target_pt_regs *regs, struct image_info *i
 
 #include "elf.h"
 
+#ifdef TARGET_PPC
+static inline uint32_t get_ppc64_abi(struct image_info *infop)
+{
+  return infop->elf_flags & EF_PPC64_ABI;
+}
+#endif
+
 struct exec
 {
     unsigned int a_info;   /* Use macros N_MAGIC, etc for access */
diff --git a/linux-user/uname.c b/linux-user/uname.c
index f5d4c66..cb1f9a3 100644
--- a/linux-user/uname.c
+++ b/linux-user/uname.c
@@ -65,6 +65,12 @@ const char *cpu_to_uname_machine(void *cpu_env)
         return "i586";
     }
     return "i686";
+#elif defined(TARGET_PPC64)
+#ifdef TARGET_WORDS_BIGENDIAN
+    return UNAME_MACHINE;
+#else
+    return UNAME_MACHINE "le";
+#endif
 #else
     /* default is #define-d in each arch/ subdir */
     return UNAME_MACHINE;
-- 
1.9.1.423.g4596e3a