[PATCH v6 36/76] x86/head/64: Load IDT earlier

Joerg Roedel
2020-08-24T08:56:43Z

Load the IDT right after switching to virtual addresses in head_64.S
so that the kernel can handle #VC exceptions.

Signed-off-by: Joerg Roedel <jroedel@suse.de>
Link: https://lore.kernel.org/r/20200724160336.5435-36-joro@8bytes.org
---
arch/x86/include/asm/setup.h | 3 +++
arch/x86/kernel/head64.c | 3 +++
arch/x86/kernel/head_64.S | 5 +++++
arch/x86/kernel/idt.c | 23 +++++++++++++++++++++++
4 files changed, 34 insertions(+)

diff --git a/arch/x86/include/asm/setup.h b/arch/x86/include/asm/setup.h
index 8aa6ba0427b0..5c09f50ecf1c 100644
--- a/arch/x86/include/asm/setup.h
+++ b/arch/x86/include/asm/setup.h
@@ -50,6 +50,8 @@ extern unsigned long __startup_64(unsigned long physaddr, struct boot_params *bp
extern unsigned long __startup_secondary_64(void);
extern void startup_64_setup_env(unsigned long physbase);
extern int early_make_pgtable(unsigned long address);
+extern void early_idt_setup_early_handler(unsigned long physaddr);
+extern void early_load_idt(void);

#ifdef CONFIG_X86_INTEL_MID
extern void x86_intel_mid_early_setup(void);
@@ -66,6 +68,7 @@ static inline void x86_ce4100_early_setup(void) { }
#ifndef _SETUP

#include <asm/espfix.h>
+#include <asm/sections.h>
#include <linux/kernel.h>

/*
diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c
index 8703292a35e9..096b09d06d1c 100644
--- a/arch/x86/kernel/head64.c
+++ b/arch/x86/kernel/head64.c
@@ -286,6 +286,9 @@ unsigned long __head __startup_64(unsigned long physaddr,
}
}

+ /* Setup IDT with early handlers */
+ early_idt_setup_early_handler(physaddr);
+
/*
* Return the SME encryption mask (if SME is active) to be used as a
* modifier for the initial pgdir entry programmed into CR3.
diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S
index a5e1939d1dc9..28de83fecda3 100644
--- a/arch/x86/kernel/head_64.S
+++ b/arch/x86/kernel/head_64.S
@@ -206,6 +206,11 @@ SYM_CODE_START(secondary_startup_64)
*/
movq initial_stack(%rip), %rsp

+ /* Load IDT */
+ pushq %rsi
+ call early_load_idt
+ popq %rsi
+
/* Check if nx is implemented */
movl $0x80000001, %eax
cpuid
diff --git a/arch/x86/kernel/idt.c b/arch/x86/kernel/idt.c
index c19773174221..e2777cc264f5 100644
--- a/arch/x86/kernel/idt.c
+++ b/arch/x86/kernel/idt.c
@@ -10,6 +10,7 @@
#include <asm/proto.h>
#include <asm/desc.h>
#include <asm/hw_irq.h>
+#include <asm/setup.h>

struct idt_data {
unsigned int vector;
@@ -385,3 +386,25 @@ void __init alloc_intr_gate(unsigned int n, const void *addr)
if (!WARN_ON(test_and_set_bit(n, system_vectors)))
set_intr_gate(n, addr);
}
+
+void __init early_idt_setup_early_handler(unsigned long physaddr)
+{
+ gate_desc *idt;
+ int i;
+
+ idt = fixup_pointer(idt_table, physaddr);
+
+ for (i = 0; i < NUM_EXCEPTION_VECTORS; i++) {
+ struct idt_data data;
+ gate_desc desc;
+
+ init_idt_data(&data, i, early_idt_handler_array[i]);
+ idt_init_desc(&desc, &data);
+ native_write_idt_entry(idt, i, &desc);
+ }
+}
+
+void early_load_idt(void)
+{
+ load_idt(&idt_descr);
+}