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Subject[PATCH 30/62] x86/head/64: Move early exception dispatch to C code
Date
From: Joerg Roedel <jroedel@suse.de>

Move the assembly coded dispatch between page-faults and all other
exceptions to C code to make it easier to maintain and extend.

Signed-off-by: Joerg Roedel <jroedel@suse.de>
---
arch/x86/kernel/head64.c | 20 ++++++++++++++++++++
arch/x86/kernel/head_64.S | 11 +----------
2 files changed, 21 insertions(+), 10 deletions(-)

diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c
index 7cdfb7113811..d83c62ebaa85 100644
--- a/arch/x86/kernel/head64.c
+++ b/arch/x86/kernel/head64.c
@@ -36,6 +36,8 @@
#include <asm/microcode.h>
#include <asm/kasan.h>
#include <asm/fixmap.h>
+#include <asm/extable.h>
+#include <asm/trap_defs.h>

/*
* Manage page tables very early on.
@@ -377,6 +379,24 @@ int __init early_make_pgtable(unsigned long address)
return __early_make_pgtable(address, pmd);
}

+void __init early_exception(struct pt_regs *regs, int trapnr)
+{
+ unsigned long cr2;
+ int r;
+
+ switch (trapnr) {
+ case X86_TRAP_PF:
+ cr2 = native_read_cr2();
+ r = early_make_pgtable(cr2);
+ break;
+ default:
+ r = 1;
+ }
+
+ if (r)
+ early_fixup_exception(regs, trapnr);
+}
+
/* Don't add a printk in there. printk relies on the PDA which is not initialized
yet. */
static void __init clear_bss(void)
diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S
index 0af79f783659..81cf6c5763ef 100644
--- a/arch/x86/kernel/head_64.S
+++ b/arch/x86/kernel/head_64.S
@@ -357,18 +357,9 @@ SYM_CODE_START_LOCAL(early_idt_handler_common)
pushq %r15 /* pt_regs->r15 */
UNWIND_HINT_REGS

- cmpq $14,%rsi /* Page fault? */
- jnz 10f
- GET_CR2_INTO(%rdi) /* can clobber %rax if pv */
- call early_make_pgtable
- andl %eax,%eax
- jz 20f /* All good */
-
-10:
movq %rsp,%rdi /* RDI = pt_regs; RSI is already trapnr */
- call early_fixup_exception
+ call early_exception

-20:
decl early_recursion_flag(%rip)
jmp restore_regs_and_return_to_kernel
SYM_CODE_END(early_idt_handler_common)
--
2.17.1
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