[patch V3 35/44] x86/idt: Switch early trap init to IDT tables

Thomas Gleixner
2017-08-28T06:56:53Z

[-- Attachment #1: x86-idt--Switch-early-trao-init-to-tables.patch --]
[-- Type: text/plain, Size: 3784 bytes --]

Add the initialization table for the early trap setup and replace the early
trap init code.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
arch/x86/kernel/idt.c | 53 ++++++++++++++++++++++++++++++++++++++++++++++++
arch/x86/kernel/setup.c | 4 +--
arch/x86/kernel/traps.c | 27 ------------------------
3 files changed, 55 insertions(+), 29 deletions(-)

--- a/arch/x86/kernel/idt.c
+++ b/arch/x86/kernel/idt.c
@@ -48,6 +48,28 @@ struct idt_data {
#define TSKG(_vector, _gdt) \
G(_vector, NULL, DEFAULT_STACK, GATE_TASK, DPL0, _gdt << 3)

+/*
+ * Early traps running on the DEFAULT_STACK because the other interrupt
+ * stacks work only after cpu_init().
+ */
+static const __initdata struct idt_data early_idts[] = {
+ INTG(X86_TRAP_DB, debug),
+ SYSG(X86_TRAP_BP, int3),
+#ifdef CONFIG_X86_32
+ INTG(X86_TRAP_PF, page_fault),
+#endif
+};
+
+#ifdef CONFIG_X86_64
+/*
+ * Early traps running on the DEFAULT_STACK because the other interrupt
+ * stacks work only after cpu_init().
+ */
+static const __initdata struct idt_data early_pf_idts[] = {
+ INTG(X86_TRAP_PF, page_fault),
+};
+#endif
+
/* Must be page-aligned because the real IDT is used in a fixmap. */
gate_desc idt_table[IDT_ENTRIES] __page_aligned_bss;

@@ -93,6 +115,37 @@ idt_setup_from_table(gate_desc *idt, con
}

/**
+ * idt_setup_early_traps - Initialize the idt table with early traps
+ *
+ * On X8664 these traps do not use interrupt stacks as they can't work
+ * before cpu_init() is invoked and sets up TSS. The IST variants are
+ * installed after that.
+ */
+void __init idt_setup_early_traps(void)
+{
+ idt_setup_from_table(idt_table, early_idts, ARRAY_SIZE(early_idts));
+ load_idt(&idt_descr);
+}
+
+#ifdef CONFIG_X86_64
+/**
+ * idt_setup_early_pf - Initialize the idt table with early pagefault handler
+ *
+ * On X8664 this does not use interrupt stacks as they can't work before
+ * 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?
+ */
+void __init idt_setup_early_pf(void)
+{
+ idt_setup_from_table(idt_table, early_pf_idts,
+ ARRAY_SIZE(early_pf_idts));
+}
+#endif
+
+/**
* idt_setup_early_handler - Initializes the idt table with early handlers
*/
void __init idt_setup_early_handler(void)
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -891,7 +891,7 @@ void __init setup_arch(char **cmdline_p)
*/
olpc_ofw_detect();

- early_trap_init();
+ idt_setup_early_traps();
early_cpu_init();
early_ioremap_init();

@@ -1162,7 +1162,7 @@ void __init setup_arch(char **cmdline_p)

init_mem_mapping();

- early_trap_pf_init();
+ idt_setup_early_pf();

/*
* Update mmu_cr4_features (and, indirectly, trampoline_cr4_features)
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -923,33 +923,6 @@ dotraplinkage void do_iret_error(struct
}
#endif

-/* Set of traps needed for early debugging. */
-void __init early_trap_init(void)
-{
- /*
- * Don't use IST to set DEBUG_STACK as it doesn't work until TSS
- * is ready in cpu_init() <-- trap_init(). Before trap_init(),
- * CPU runs at ring 0 so it is impossible to hit an invalid
- * stack. Using the original stack works well enough at this
- * early stage. DEBUG_STACK will be equipped after cpu_init() in
- * trap_init().
- */
- set_intr_gate(X86_TRAP_DB, debug);
- /* int3 can be called from all */
- set_system_intr_gate(X86_TRAP_BP, &int3);
-#ifdef CONFIG_X86_32
- set_intr_gate(X86_TRAP_PF, page_fault);
-#endif
- load_idt(&idt_descr);
-}
-
-void __init early_trap_pf_init(void)
-{
-#ifdef CONFIG_X86_64
- set_intr_gate(X86_TRAP_PF, page_fault);
-#endif
-}
-
void __init trap_init(void)
{
int i;