f

Author: mkroening

src/arch/x86_64/platform/pvh/entry.s

@@ -5,15 +5,17 @@
 
 .code32
 
-.macro gotpcrel reg, sym
+.macro movgot reg, sym
     call 2f
 2:
-    pop eax
+    pop \reg
 3:
+// LLVM currently rejects the equivalent Intel syntax:
+// https://github.com/llvm/llvm-project/issues/161550
 .att_syntax prefix
-    addl $_GLOBAL_OFFSET_TABLE_ + (3b - 2b), %eax
+    addl $_GLOBAL_OFFSET_TABLE_ + (3b - 2b), %\reg
 .intel_syntax noprefix
-    mov \reg, dword ptr [eax + \sym@GOT]
+    mov \reg, dword ptr [\reg + \sym@GOT]
 .endm
 
 .section .text
@@ -23,16 +25,7 @@ _start:
     mov edi, ebx
     cli # avoid any interrupt
 
-    call 2f
-    2:
-    pop eax
-    3:
-    .att_syntax prefix
-    addl $_GLOBAL_OFFSET_TABLE_ + (3b - 2b), %eax
-    .intel_syntax noprefix
-    mov esp, dword ptr [eax + {stack}@GOT]
-
-
+    movgot esp, {stack}
     # Initialize stack pointer
     add esp, {stack_top_offset}
 
@@ -44,36 +37,8 @@ _start:
 # Bootstrap page tables are loaded and page size
 # extensions (huge pages) enabled.
 cpu_init:
-    # check for long mode
-
-    # do we have the instruction cpuid?
-    pushfd
-    pop eax
-    mov ecx, eax
-    xor eax, 1 << 21
-    push eax
-    popfd
-    pushfd
-    pop eax
-    push ecx
-    popfd
-    xor eax, ecx
-    jz Linvalid
-
-    # cpuid > 0x80000000?
-    mov eax, 0x80000000
-    cpuid
-    cmp eax, 0x80000001
-    jb Linvalid # It is less, there is no long mode.
-
-    # do we have a long mode?
-    mov eax, 0x80000001
-    cpuid
-    test edx, 1 << 29 # Test if the LM-bit, which is bit 29, is set in the D-register.
-    jz Linvalid # They aren't, there is no long mode.
-
     # Set CR3
-    gotpcrel eax, {level_4_table}
+    movgot eax, {level_4_table}
     mov cr3, eax
 
     # we need to enable PAE modus
@@ -103,12 +68,12 @@ cpu_init:
     or eax, (1 << 31)       # enable paging
     mov cr0, eax
 
-    gotpcrel eax, {gdt_ptr}
+    movgot eax, {gdt_ptr}
 
     lgdt [eax] # Load the 64-bit global descriptor table.
 
     push {kernel_code_selector}
-    gotpcrel eax, start64
+    movgot eax, start64
     push eax
     retf
     # https://github.com/llvm/llvm-project/issues/46048