[patch V3 34/44] x86/idt: Prepare for table based init

Thomas Gleixner
2017-08-28T06:56:54Z

[-- Attachment #1: x86-idt--Prepare-for-table-based-init.patch --]
[-- Type: text/plain, Size: 2518 bytes --]

The IDT setup code is handled in several places. All of them use variants
of set_intr_gate() inlines. This can be done with a table based
initialization, which allows to reduce the inline zoo and puts all IDT
related code and information into a single place.

Add the infrastructure.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
arch/x86/kernel/idt.c | 67 ++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 67 insertions(+)

--- a/arch/x86/kernel/idt.c
+++ b/arch/x86/kernel/idt.c
@@ -5,8 +5,49 @@
*/
#include <linux/interrupt.h>

+#include <asm/traps.h>
+#include <asm/proto.h>
#include <asm/desc.h>

+struct idt_data {
+ unsigned int vector;
+ unsigned int segment;
+ struct idt_bits bits;
+ const void *addr;
+};
+
+#define DPL0 0x0
+#define DPL3 0x3
+
+#define DEFAULT_STACK 0
+
+#define G(_vector, _addr, _ist, _type, _dpl, _segment) \
+ { \
+ .vector = _vector, \
+ .bits.ist = _ist, \
+ .bits.type = _type, \
+ .bits.dpl = _dpl, \
+ .bits.p = 1, \
+ .addr = _addr, \
+ .segment = _segment, \
+ }
+
+/* Interrupt gate */
+#define INTG(_vector, _addr) \
+ G(_vector, _addr, DEFAULT_STACK, GATE_INTERRUPT, DPL0, __KERNEL_CS)
+
+/* System interrupt gate */
+#define SYSG(_vector, _addr) \
+ G(_vector, _addr, DEFAULT_STACK, GATE_INTERRUPT, DPL3, __KERNEL_CS)
+
+/* Interrupt gate with interrupt stack */
+#define ISTG(_vector, _addr, _ist) \
+ G(_vector, _addr, _ist, GATE_INTERRUPT, DPL0, __KERNEL_CS)
+
+/* Task gate */
+#define TSKG(_vector, _gdt) \
+ G(_vector, NULL, DEFAULT_STACK, GATE_TASK, DPL0, _gdt << 3)
+
/* Must be page-aligned because the real IDT is used in a fixmap. */
gate_desc idt_table[IDT_ENTRIES] __page_aligned_bss;

@@ -25,6 +66,32 @@ const struct desc_ptr debug_idt_descr =
};
#endif

+static inline void idt_init_desc(gate_desc *gate, const struct idt_data *d)
+{
+ unsigned long addr = (unsigned long) d->addr;
+
+ gate->offset_low = (u16) addr;
+ gate->segment = (u16) d->segment;
+ gate->bits = d->bits;
+ gate->offset_middle = (u16) (addr >> 16);
+#ifdef CONFIG_X86_64
+ gate->offset_high = (u32) (addr >> 32);
+ gate->reserved = 0;
+#endif
+}
+
+static __init void
+idt_setup_from_table(gate_desc *idt, const struct idt_data *t, int size)
+{
+ gate_desc desc;
+
+ for (; size > 0; t++, size--) {
+ idt_init_desc(&desc, t);
+ set_bit(t->vector, used_vectors);
+ write_idt_entry(idt, t->vector, &desc);
+ }
+}
+
/**
* idt_setup_early_handler - Initializes the idt table with early handlers
*/