x86: early_idt_handler improvements, 64-bit

It's not too pretty, but I found this made the "PANIC: early exception"
messages become much more reliably useful: 1. print the vector number,
2. print the %cs value, 3. handle error-code-pushing vs non-pushing vectors.

Signed-off-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c
index 4a1c1356c41a55ea56a23dd86b8968cd4681b845..85c1e6bf80225e78607413c4fe1e2ce9a01c5e5d 100644 (file)
--- a/arch/x86/kernel/head64.c
+++ b/arch/x86/kernel/head64.c
@@ -59,7 +59,7 @@ void __init x86_64_start_kernel(char * real_mode_data)
        zap_identity_mappings();
 
        for (i = 0; i < IDT_ENTRIES; i++)
-               set_intr_gate(i, early_idt_handler);
+               set_intr_gate(i, &early_idt_handlers[i]);
        load_idt((const struct desc_ptr *)&idt_descr);
 
        early_printk("Kernel alive\n");

diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S
index c31b1c96a9d3bafade469a02c8a9f456c5a92415..8b4c35cb519a39d2a2bb607b5740ac50e3bd369a 100644 (file)
--- a/arch/x86/kernel/head_64.S
+++ b/arch/x86/kernel/head_64.S
@@ -267,14 +267,40 @@ init_rsp:
 bad_address:
        jmp bad_address
 
+.macro early_idt_tramp first, last
+       .ifgt \last-\first
+       early_idt_tramp \first, \last-1
+       .endif
+       movl $\last,%esi
+       jmp early_idt_handler
+.endm
+
+       .globl early_idt_handlers
+early_idt_handlers:
+       early_idt_tramp 0, 63
+       early_idt_tramp 64, 127
+       early_idt_tramp 128, 191
+       early_idt_tramp 192, 255
+
 ENTRY(early_idt_handler)
        cmpl $2,early_recursion_flag(%rip)
        jz  1f
        incl early_recursion_flag(%rip)
-       xorl %eax,%eax
-       movq 8(%rsp),%rsi       # get rip
-       movq (%rsp),%rdx
        GET_CR2_INTO_RCX
+       movq %rcx,%r9
+       xorl %r8d,%r8d          # zero for error code
+       movl %esi,%ecx          # get vector number
+       # Test %ecx against mask of vectors that push error code.
+       cmpl $31,%ecx
+       ja 0f
+       movl $1,%eax
+       salq %cl,%rax
+       testl $0x27d00,%eax
+       je 0f
+       popq %r8                # get error code
+0:     movq 0(%rsp),%rcx       # get ip
+       movq 8(%rsp),%rdx       # get cs
+       xorl %eax,%eax
        leaq early_idt_msg(%rip),%rdi
        call early_printk
        cmpl $2,early_recursion_flag(%rip)
@@ -291,7 +317,7 @@ early_recursion_flag:
        .long 0
 
 early_idt_msg:
-       .asciz "PANIC: early exception rip %lx error %lx cr2 %lx\n"
+       .asciz "PANIC: early exception %02lx rip %lx:%lx error %lx cr2 %lx\n"
 early_idt_ripmsg:
        .asciz "RIP %s\n"
 

diff --git a/include/asm-x86/segment.h b/include/asm-x86/segment.h
index 57c8d37238366eac1304af89e4ca7c64d9af38fa..23f0535fec618beb3c909924ff82d8c4b063b0ca 100644 (file)
--- a/include/asm-x86/segment.h
+++ b/include/asm-x86/segment.h
@@ -195,4 +195,10 @@
 #define GDT_ENTRY_TLS_ENTRIES 3
 #define TLS_SIZE (GDT_ENTRY_TLS_ENTRIES * 8)
 
+#ifdef __KERNEL__
+#ifndef __ASSEMBLY__
+extern const char early_idt_handlers[IDT_ENTRIES][10];
+#endif
+#endif
+
 #endif