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authorThomas Gleixner <tglx@linutronix.de>2020-05-28 16:53:17 +0200
committerThomas Gleixner <tglx@linutronix.de>2020-06-11 15:15:25 +0200
commit94438af40d06c110988fc9e30baf801f38b1491a (patch)
treef90a9a78e07fb7b4e466ed9798ed31d4565e2123 /arch
parentbdf5bde8aec7b53d0ea3a44d880a4e5106ff37f3 (diff)
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> Link: https://lkml.kernel.org/r/20200528145522.807135882@linutronix.de
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/kernel/idt.c10
1 files changed, 8 insertions, 2 deletions
diff --git a/arch/x86/kernel/idt.c b/arch/x86/kernel/idt.c
index 4b99f7bec384..5ef82fcf333d 100644
--- 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
};
@@ -256,8 +260,10 @@ 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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