From: David Woodhouse <d...@amazon.co.uk>
Signed-off-by: David Woodhouse <d...@amazon.co.uk>
---
arch/x86/kernel/relocate_kernel_64.S | 83 +++++++++++++++++++++++++++-
1 file changed, 80 insertions(+), 3 deletions(-)
diff --git a/arch/x86/kernel/relocate_kernel_64.S
b/arch/x86/kernel/relocate_kernel_64.S
index 4ace2577afc6..67f6853c7abe 100644
--- a/arch/x86/kernel/relocate_kernel_64.S
+++ b/arch/x86/kernel/relocate_kernel_64.S
@@ -400,6 +400,55 @@ SYM_CODE_START_LOCAL_NOALIGN(swap_pages)
SYM_CODE_END(swap_pages)
#ifdef DEBUG
+/*
+ * This allows other types of serial ports to be used.
+ * - %al: Character to be printed (no clobber %rax)
+ * - %rdx: MMIO address or port.
+ */
+.macro pr_char
+ outb %al, %dx
+.endm
+
+/* Print the nybble in %bl, clobber %rax */
+SYM_CODE_START_LOCAL_NOALIGN(pr_nybble)
+ UNWIND_HINT_FUNC
+ movb %bl, %al
+ nop
+ andb $0x0f, %al
+ addb $0x30, %al
+ cmpb $0x3a, %al
+ jb 1f
+ addb $('a' - '0' - 10), %al
+1: pr_char
+ ANNOTATE_UNRET_SAFE
+ ret
+SYM_CODE_END(pr_nybble)
+
+SYM_CODE_START_LOCAL_NOALIGN(pr_qword)
+ UNWIND_HINT_FUNC
+ movq $16, %rcx
+1: rolq $4, %rbx
+ call pr_nybble
+ loop 1b
+ movb $'\n', %al
+ pr_char
+ ANNOTATE_UNRET_SAFE
+ ret
+SYM_CODE_END(pr_qword)
+
+.macro print_reg a, b, c, d, r
+ movb $\a, %al
+ pr_char
+ movb $\b, %al
+ pr_char
+ movb $\c, %al
+ pr_char
+ movb $\d, %al
+ pr_char
+ movq \r, %rbx
+ call pr_qword
+.endm
+
SYM_CODE_START_LOCAL_NOALIGN(exc_vectors)
/* Each of these is 6 bytes. */
.macro vec_err exc
@@ -439,11 +488,39 @@ SYM_CODE_END(exc_vectors)
SYM_CODE_START_LOCAL_NOALIGN(exc_handler)
pushq %rax
+ pushq %rbx
+ pushq %rcx
pushq %rdx
+
movw $0x3f8, %dx
- movb $'A', %al
- outb %al, %dx
+
+ /* rip and exception info */
+ print_reg 'E', 'x', 'c', ':', 32(%rsp)
+ print_reg 'E', 'r', 'r', ':', 40(%rsp)
+ print_reg 'r', 'i', 'p', ':', 48(%rsp)
+
+ /* We spilled these to the stack */
+ print_reg 'r', 'a', 'x', ':', 24(%rsp)
+ print_reg 'r', 'b', 'x', ':', 16(%rsp)
+ print_reg 'r', 'c', 'x', ':', 8(%rsp)
+ print_reg 'r', 'd', 'x', ':', (%rsp)
+
+ /* Other registers */
+ print_reg 'r', 's', 'i', ':', %rsi
+ print_reg 'r', 'd', 'i', ':', %rdi
+ print_reg 'r', '8', ' ', ':', %r8
+ print_reg 'r', '9', ' ', ':', %r9
+ print_reg 'r', '1', '0', ':', %r10
+ print_reg 'r', '1', '1', ':', %r11
+ print_reg 'r', '1', '2', ':', %r12
+ print_reg 'r', '1', '3', ':', %r13
+ print_reg 'r', '1', '4', ':', %r14
+ print_reg 'r', '1', '5', ':', %r15
+ print_reg 'c', 'r', '2', ':', %cr2
+
popq %rdx
+ popq %rcx
+ popq %rbx
popq %rax
/* Only return from int3 */
@@ -456,6 +533,6 @@ SYM_CODE_START_LOCAL_NOALIGN(exc_handler)
.Ldie:
hlt
jmp .Ldie
-
+ int3
SYM_CODE_END(exc_handler)
#endif /* DEBUG */
--
2.47.0
