[U-Boot] [PATCH v0 5/7] x86: Ensure IDT and GDT remain 16-byte aligned post relocation

Graeme Russ
2011-11-05T02:21:49Z

Some CPUs have strict alignment requirements for these tables

Signed-off-by: Graeme Russ <graeme.russ@gmail.com>
---
arch/x86/cpu/interrupts.c | 2 +-
arch/x86/lib/board.c | 17 ++++++++++++-----
2 files changed, 13 insertions(+), 6 deletions(-)

diff --git a/arch/x86/cpu/interrupts.c b/arch/x86/cpu/interrupts.c
index c6e72ea..b501fed 100644
--- a/arch/x86/cpu/interrupts.c
+++ b/arch/x86/cpu/interrupts.c
@@ -172,7 +172,7 @@ struct desc_ptr {
unsigned short segment;
} __attribute__((packed));

-struct idt_entry idt[256];
+struct idt_entry idt[256] __attribute__((aligned(16)));

struct desc_ptr idt_ptr;

diff --git a/arch/x86/lib/board.c b/arch/x86/lib/board.c
index 0938104..c5a0b71 100644
--- a/arch/x86/lib/board.c
+++ b/arch/x86/lib/board.c
@@ -180,19 +180,26 @@ gd_t *gd;

static int calculate_relocation_address(void)
{
- void *text_start = &__text_start;
- void *bss_end = &__bss_end;
- void *dest_addr;
+ ulong text_start = (ulong)&__text_start;
+ ulong bss_end = (ulong)&__bss_end;
+ ulong dest_addr;
ulong rel_offset;

/* Calculate destination RAM Address and relocation offset */
- dest_addr = (void *)gd->ram_size;
+ dest_addr = gd->ram_size;
dest_addr -= CONFIG_SYS_STACK_SIZE;
dest_addr -= (bss_end - text_start);
+
+ /*
+ * Round destination address down to 16-byte boundary to keep
+ * IDT and GDT 16-byte aligned
+ */
+ dest_addr &= ~15;
+
rel_offset = dest_addr - text_start;

gd->start_addr_sp = gd->ram_size;
- gd->relocaddr = (ulong)dest_addr;
+ gd->relocaddr = dest_addr;
gd->reloc_off = rel_offset;

return 0;
--
1.7.5.2.317.g391b14