Commit ac630dd9 authored by Linus Torvalds's avatar Linus Torvalds

x86-64: don't set the early IDT to point directly to 'early_idt_handler'

The code requires the use of the proper per-exception-vector stub
functions (set up as the early_idt_handlers[] array - note the 's') that
make sure to set up the error vector number.  This is true regardless of
whether CONFIG_EARLY_PRINTK is set or not.

Why? The stack offset for the comparison of __KERNEL_CS won't be right
otherwise, nor will the new check (from commit 8170e6be: "x86,
64bit: Use a #PF handler to materialize early mappings on demand") for
the page fault exception vector.
Acked-by: default avatarH. Peter Anvin <hpa@zytor.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 2ef14f46
......@@ -5,8 +5,6 @@
/* misc architecture specific prototypes */
void early_idt_handler(void);
void system_call(void);
void syscall_init(void);
......
......@@ -159,13 +159,8 @@ void __init x86_64_start_kernel(char * real_mode_data)
/* clear bss before set_intr_gate with early_idt_handler */
clear_bss();
for (i = 0; i < NUM_EXCEPTION_VECTORS; i++) {
#ifdef CONFIG_EARLY_PRINTK
for (i = 0; i < NUM_EXCEPTION_VECTORS; i++)
set_intr_gate(i, &early_idt_handlers[i]);
#else
set_intr_gate(i, early_idt_handler);
#endif
}
load_idt((const struct desc_ptr *)&idt_descr);
copy_bootdata(__va(real_mode_data));
......
......@@ -336,6 +336,7 @@ early_idt_handlers:
i = i + 1
.endr
/* This is global to keep gas from relaxing the jumps */
ENTRY(early_idt_handler)
cld
......@@ -404,6 +405,7 @@ ENTRY(early_idt_handler)
addq $16,%rsp # drop vector number and error code
decl early_recursion_flag(%rip)
INTERRUPT_RETURN
ENDPROC(early_idt_handler)
__INITDATA
......
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