Changeset 3bdcf57 in mainline for kernel/arch/amd64/src/asm.S

Timestamp:

2019-05-31T17:51:02Z (5 years ago)

Author:

Jakub Jermar <jakub@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

de9e28e

Parents:

77de449e

Message:

Add support for L4Re's uvmm early print

This is useful when running as a guest under L4Re's uvmm.

File:

• kernel/arch/amd64/src/asm.S (modified) (2 diffs)

kernel/arch/amd64/src/asm.S

@@ -398 +398 @@
         .asciz "Invalid instruction pointer."
 
-/** Print Unicode character to EGA display.
- *
- * If CONFIG_EGA is undefined or CONFIG_FB is defined
- * then this function does nothing.
+/** Print Unicode character to an early display device.
  *
  * Since the EGA can only display Extended ASCII (usually
@@ -413 +410 @@
  */
 FUNCTION_BEGIN(early_putwchar)
+
+#if (defined(CONFIG_L4RE_UVMM_EARLY_PRINT))
+        xorl %eax, %eax  /* RAX==0: uvmm's print hypercall */
+        mov %rdi, %rcx   /* RCX:    printed character */
+        vmcall
+#endif
+
 #if ((defined(CONFIG_EGA)) && (!defined(CONFIG_FB)))