[OpenBIOS] [PATCH 1/2] ppc: Dereference function descriptors on ppc64

[Andreas Färber]

In the ppc64 ELF ABI, similar to ia64, a function's symbol does not directly
precede its machine instructions. For ppc64 it consists of a triple of
entry point, TOC base and environment pointer.

Introduce macros to facilitate handling this.
Names suggested by Blue.

Deliberately don't touch the client interface yet, as there's more work to do.

Cc: Alexander Graf 
Cc: Blue Swirl 
Signed-off-by: Andreas Färber 
---
 arch/ppc/qemu/start.S      |   10 +++++-----
 include/arch/ppc/asmdefs.h |   13 +++++++++++++
 2 files changed, 18 insertions(+), 5 deletions(-)

diff --git a/arch/ppc/qemu/start.S b/arch/ppc/qemu/start.S
index eef4293..f5c2f24 100644
--- a/arch/ppc/qemu/start.S
+++ b/arch/ppc/qemu/start.S
@@ -271,13 +271,13 @@ GLOBL(__vectors):
    b	1b

call_dsi_exception:
-	LOAD_REG_IMMEDIATE(r3, dsi_exception)
+	LOAD_REG_FUNC(r3, dsi_exception)
    mtctr	r3
    bctrl
    b	exception_return

call_isi_exception:
-	LOAD_REG_IMMEDIATE(r3, isi_exception)
+	LOAD_REG_FUNC(r3, isi_exception)
    mtctr	r3
    bctrl
    b	exception_return
@@ -289,7 +289,7 @@ exception_return:
 __divide_error:
 trap_error:
    mflr	r3
-	b	unexpected_excep
+	b	BRANCH_LABEL(unexpected_excep)

VECTOR( 0x100, "SRE" ):
         b       _entry
@@ -445,8 +445,8 @@ GLOBL(_entry):

/* save memory size in stack */

-	bl	setup_mmu
-	bl	entry
+	bl	BRANCH_LABEL(setup_mmu)
+	bl	BRANCH_LABEL(entry)
 1:	nop
    b	1b

diff --git a/include/arch/ppc/asmdefs.h b/include/arch/ppc/asmdefs.h
index 51570ea..9c85ea5 100644
--- a/include/arch/ppc/asmdefs.h
+++ b/include/arch/ppc/asmdefs.h
@@ -76,24 +76,37 @@
 /************************************************************************/

#ifdef __powerpc64__
+
 #define LOAD_REG_IMMEDIATE(D, x) \
    lis  (D),      (x)@highest ; \
    ori  (D), (D), (x)@higher ; \
    sldi (D), (D), 32 ; \
    oris (D), (D), (x)@h ; \
    ori  (D), (D), (x)@l
+
+#define LOAD_REG_FUNC(D, x) \
+    LOAD_REG_IMMEDIATE((D), (x)) ; \
+    ld (D), 0(D)
+
 #else
+
 #define LOAD_REG_IMMEDIATE(D, x) \
    lis  (D),      HA(x) ; \
    addi (D), (D), LO(x)
+
+#define LOAD_REG_FUNC(D, x) \
+    LOAD_REG_IMMEDIATE((D), (x))
+
 #endif

#ifdef __powerpc64__
 #define RFI rfid
 #define MTMSRD(r) mtmsrd r
+#define BRANCH_LABEL(name) . ## name
 #else
 #define RFI rfi
 #define MTMSRD(r) mtmsr  r
+#define BRANCH_LABEL(name) name
 #endif

#ifndef __darwin__