[tip:x86/apic] x86/idt: Move early IDT setup out of 32-bit asm

tip-bot for Thomas Gleixner
2017-08-29T11:23:04Z

Commit-ID: 87e81786b13b267c4355e0d23e33c7e4c08fa63f
Gitweb: http://git.kernel.org/tip/87e81786b13b267c4355e0d23e33c7e4c08fa63f
Author: Thomas Gleixner <tglx@linutronix.de>
AuthorDate: Mon, 28 Aug 2017 08:47:48 +0200
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Tue, 29 Aug 2017 12:07:26 +0200

x86/idt: Move early IDT setup out of 32-bit asm

The early IDT setup can be done in C code like it's done on 64-bit kernels.
Reuse the 64-bit version.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/20170828064958.757980775@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/include/asm/segment.h | 1 +
arch/x86/kernel/head32.c | 4 ++++
arch/x86/kernel/head_32.S | 36 ++----------------------------------
arch/x86/kernel/idt.c | 4 ++++
4 files changed, 11 insertions(+), 34 deletions(-)

diff --git a/arch/x86/include/asm/segment.h b/arch/x86/include/asm/segment.h
index 5a602d6..066aaf8 100644
--- a/arch/x86/include/asm/segment.h
+++ b/arch/x86/include/asm/segment.h
@@ -238,6 +238,7 @@
#ifndef __ASSEMBLY__

extern const char early_idt_handler_array[NUM_EXCEPTION_VECTORS][EARLY_IDT_HANDLER_SIZE];
+extern void early_ignore_irq(void);

/*
* Load a segment. Fall back on loading the zero segment if something goes
diff --git a/arch/x86/kernel/head32.c b/arch/x86/kernel/head32.c
index 538ec01..cf2ce06 100644
--- a/arch/x86/kernel/head32.c
+++ b/arch/x86/kernel/head32.c
@@ -10,6 +10,7 @@
#include <linux/mm.h>
#include <linux/memblock.h>

+#include <asm/desc.h>
#include <asm/setup.h>
#include <asm/sections.h>
#include <asm/e820/api.h>
@@ -30,6 +31,9 @@ static void __init i386_default_early_setup(void)
asmlinkage __visible void __init i386_start_kernel(void)
{
cr4_init_shadow();
+
+ idt_setup_early_handler();
+
sanitize_boot_params(&boot_params);

x86_early_init_platform_quirks();
diff --git a/arch/x86/kernel/head_32.S b/arch/x86/kernel/head_32.S
index ce8c6ed..a615a5e 100644
--- a/arch/x86/kernel/head_32.S
+++ b/arch/x86/kernel/head_32.S
@@ -345,7 +345,6 @@ ENTRY(startup_32_smp)
movl %eax,%cr0

lgdt early_gdt_descr
- lidt idt_descr
ljmp $(__KERNEL_CS),$1f
1: movl $(__KERNEL_DS),%eax # reload all the segment registers
movl %eax,%ss # after changing gdt.
@@ -378,37 +377,6 @@ ENDPROC(startup_32_smp)
*/
__INIT
setup_once:
- /*
- * Set up a idt with 256 interrupt gates that push zero if there
- * is no error code and then jump to early_idt_handler_common.
- * It doesn't actually load the idt - that needs to be done on
- * each CPU. Interrupts are enabled elsewhere, when we can be
- * relatively sure everything is ok.
- */
-
- movl $idt_table,%edi
- movl $early_idt_handler_array,%eax
- movl $NUM_EXCEPTION_VECTORS,%ecx
-1:
- movl %eax,(%edi)
- movl %eax,4(%edi)
- /* interrupt gate, dpl=0, present */
- movl $(0x8E000000 + __KERNEL_CS),2(%edi)
- addl $EARLY_IDT_HANDLER_SIZE,%eax
- addl $8,%edi
- loop 1b
-
- movl $256 - NUM_EXCEPTION_VECTORS,%ecx
- movl $ignore_int,%edx
- movl $(__KERNEL_CS << 16),%eax
- movw %dx,%ax /* selector = 0x0010 = cs */
- movw $0x8E00,%dx /* interrupt gate - dpl=0, present */
-2:
- movl %eax,(%edi)
- movl %edx,4(%edi)
- addl $8,%edi
- loop 2b
-
#ifdef CONFIG_CC_STACKPROTECTOR
/*
* Configure the stack canary. The linker can't handle this by
@@ -498,7 +466,7 @@ ENDPROC(early_idt_handler_common)

/* This is the default interrupt "handler" :-) */
ALIGN
-ignore_int:
+ENTRY(early_ignore_irq)
cld
#ifdef CONFIG_PRINTK
pushl %eax
@@ -533,7 +501,7 @@ ignore_int:
hlt_loop:
hlt
jmp hlt_loop
-ENDPROC(ignore_int)
+ENDPROC(early_ignore_irq)
__INITDATA
.align 4
GLOBAL(early_recursion_flag)
diff --git a/arch/x86/kernel/idt.c b/arch/x86/kernel/idt.c
index a147581..70ca248 100644
--- a/arch/x86/kernel/idt.c
+++ b/arch/x86/kernel/idt.c
@@ -34,6 +34,10 @@ void __init idt_setup_early_handler(void)

for (i = 0; i < NUM_EXCEPTION_VECTORS; i++)
set_intr_gate(i, early_idt_handler_array[i]);
+#ifdef CONFIG_X86_32
+ for ( ; i < NR_VECTORS; i++)
+ set_intr_gate(i, early_ignore_irq);
+#endif
load_idt(&idt_descr);
}