x86: Set up the global data pointer in C instead of asm

We currently assume that the global data pointer is at the start of
struct global_data. We want to remove this restriction, and it is
easiest to do this in C.

Remove the asm code and add equivalent code in C.

This idea was proposed by Graeme Russ here:
   http://patchwork.ozlabs.org/patch/199741/

Signed-off-by: Simon Glass <sjg@chromium.org>
[trini: Apply Graeme Russ' comments
http://patchwork.ozlabs.org/patch/206305/ here, re-order]
Signed-off-by: Tom Rini <trini@ti.com>

diff --git a/arch/x86/cpu/cpu.c b/arch/x86/cpu/cpu.c
index 315e87a..4902f8b 100644 (file)
--- a/arch/x86/cpu/cpu.c
+++ b/arch/x86/cpu/cpu.c
@@ -100,7 +100,9 @@ void setup_gdt(gd_t *id, u64 *gdt_addr)
        gdt_addr[X86_GDT_ENTRY_32BIT_DS] = GDT_ENTRY(0xc093, 0, 0xfffff);
 
        /* FS: data, read/write, 4 GB, base (Global Data Pointer) */
-       gdt_addr[X86_GDT_ENTRY_32BIT_FS] = GDT_ENTRY(0xc093, (ulong)id, 0xfffff);
+       id->gd_addr = id;
+       gdt_addr[X86_GDT_ENTRY_32BIT_FS] = GDT_ENTRY(0xc093,
+                    (ulong)&id->gd_addr, 0xfffff);
 
        /* 16-bit CS: code, read/execute, 64 kB, base 0 */
        gdt_addr[X86_GDT_ENTRY_16BIT_CS] = GDT_ENTRY(0x109b, 0, 0x0ffff);

diff --git a/arch/x86/cpu/start.S b/arch/x86/cpu/start.S
index e960e21..f389584 100644 (file)
--- a/arch/x86/cpu/start.S
+++ b/arch/x86/cpu/start.S
@@ -113,9 +113,6 @@ car_init_ret:
        /* Set second parameter to setup_gdt */
        movl    %esp, %edx
 
-       /* gd->gd_addr = gd (Required to allow gd->xyz to work) */
-       movl    %eax, (%eax)
-
        /* Setup global descriptor table so gd->xyz works */
        call    setup_gdt
 
@@ -171,9 +168,6 @@ board_init_f_r_trampoline:
        /* Set second parameter to setup_gdt */
        movl    %esp, %edx
 
-       /* gd->gd_addr = gd (Required to allow gd->xyz to work) */
-       movl    %eax, (%eax)
-
        /* Setup global descriptor table so gd->xyz works */
        call    setup_gdt