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Subject[patch 2/5] x86/idt: Add comments about early #PF handling
The difference between 32 and 64 bit vs. early #PF handling is not
documented. Replace the FIXME at idt_setup_early_pf() with proper comments.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
arch/x86/kernel/idt.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)

--- a/arch/x86/kernel/idt.c
+++ b/arch/x86/kernel/idt.c
@@ -61,7 +61,11 @@ static bool idt_setup_done __initdata;
static const __initconst struct idt_data early_idts[] = {
INTG(X86_TRAP_DB, asm_exc_debug),
SYSG(X86_TRAP_BP, asm_exc_int3),
+
#ifdef CONFIG_X86_32
+ /*
+ * Not possible on 64-bit. See idt_setup_early_pf() for details.
+ */
INTG(X86_TRAP_PF, asm_exc_page_fault),
#endif
};
@@ -276,8 +280,10 @@ void __init idt_setup_traps(void)
* cpu_init() is invoked and sets up TSS. The IST variant is installed
* after that.
*
- * FIXME: Why is 32bit and 64bit installing the PF handler at different
- * places in the early setup code?
+ * Note, that X86_64 cannot install the real #PF handler in
+ * idt_setup_early_traps() because the memory intialization needs the #PF
+ * handler from the early_idt_handler_array to initialize the early page
+ * tables.
*/
void __init idt_setup_early_pf(void)
{
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