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

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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>
This commit is contained in:
Simon Glass 2012-12-13 20:48:42 +00:00 committed by Tom Rini
parent df4aa625a2
commit 0cecc3b679
2 changed files with 3 additions and 7 deletions
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4
arch/x86/cpu/cpu.c
View File

@ -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);

6
arch/x86/cpu/start.S
View File

@ -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