From: Waldemar Kozaczuk <[email protected]>
Committer: Waldemar Kozaczuk <[email protected]>
Branch: master
Fix compilation error of vmlinux-boot64.S
This patch removes macro setup_64bit_long_mode in setup.S
meant to remove duplication of logic between boot.S and vmlinux-boot.S.
Even though the logic of setting up 64 bit mode in both regular
OSv boot phase and vmlinux-like one as required by firecracker, is
identical there are some subtle differences of what registers -
specifically rax vs eax is used depending if that is 32-bit or 64-bit code.
Depending on the version of gcc or gas used old macro code would
sometimes not compile.
This patch effectively duplicates this ten assembly instructions
in a bid to make build tools happy and generate correct machine code.
Signed-off-by: Waldemar Kozaczuk <[email protected]>
---
diff --git a/arch/x64/boot.S b/arch/x64/boot.S
--- a/arch/x64/boot.S
+++ b/arch/x64/boot.S
@@ -4,7 +4,18 @@
# BSD license as described in the LICENSE file in the top-level directory.
#include "processor-flags.h"
-#include "setup.S"
+
+#define BOOT_CR0 ( X86_CR0_PE \
+ | X86_CR0_WP \
+ | X86_CR0_PG )
+
+#define BOOT_CR4 ( X86_CR4_DE \
+ | X86_CR4_PSE \
+ | X86_CR4_PAE \
+ | X86_CR4_PGE \
+ | X86_CR4_PCE \
+ | X86_CR4_OSFXSR \
+ | X86_CR4_OSXMMEXCPT )
.text
.code32
@@ -65,7 +76,26 @@ start32:
ljmp $0x18, $1f
1:
and $~7, %esp
- setup_64bit_long_mode
+ # Enable PAE (Physical Address Extension) - ability to address 64GB
+ # TODO: Add more comments to processor-flags.h what each flag does
+ mov $BOOT_CR4, %eax
+ mov %eax, %cr4
+
+ # Set root of a page table in cr3
+ lea ident_pt_l4, %eax
+ mov %eax, %cr3
+
+ # Set long mode
+ mov $0xc0000080, %ecx // EFER MSR number
+ mov $0x00000900, %eax // Set LME = 1
+ xor %edx, %edx
+ wrmsr // Write contents of EDX:EAX (0:to Model Specific Register
specified by ECX register
+
+ # Activate paging and ...?
+ # TODO: Add more comments to processor-flags.h what each flag does
+ mov $BOOT_CR0, %eax
+ mov %eax, %cr0
+
ljmpl $8, $start64
.code64
.global start64
diff --git a/arch/x64/setup.S b/arch/x64/setup.S
--- a/arch/x64/setup.S
+++ b/arch/x64/setup.S
@@ -1,38 +0,0 @@
-# Copyright (C) 2019 Waldemar Kozaczuk
-#
-# This work is open source software, licensed under the terms of the
-# BSD license as described in the LICENSE file in the top-level directory.
-
-#define BOOT_CR0 ( X86_CR0_PE \
- | X86_CR0_WP \
- | X86_CR0_PG )
-
-#define BOOT_CR4 ( X86_CR4_DE \
- | X86_CR4_PSE \
- | X86_CR4_PAE \
- | X86_CR4_PGE \
- | X86_CR4_PCE \
- | X86_CR4_OSFXSR \
- | X86_CR4_OSXMMEXCPT )
-
-.macro setup_64bit_long_mode
- // Enable PAE (Physical Address Extension) - ability to address 64GB
- // TODO: Add more comments to processor-flags.h what each flag does
- mov $BOOT_CR4, %eax
- mov %eax, %cr4
-
- // Set root of a page table in cr3
- lea ident_pt_l4, %eax
- mov %eax, %cr3
-
- // Set long mode
- mov $0xc0000080, %ecx // EFER MSR number
- mov $0x00000900, %eax // Set LME = 1
- xor %edx, %edx
- wrmsr // Write contents of EDX:EAX (0:to Model Specific Register
specified by ECX register
-
- // Activate paging and ...?
- // TODO: Add more comments to processor-flags.h what each flag does
- mov $BOOT_CR0, %eax
- mov %eax, %cr0
-.endm
diff --git a/arch/x64/vmlinux-boot64.S b/arch/x64/vmlinux-boot64.S
--- a/arch/x64/vmlinux-boot64.S
+++ b/arch/x64/vmlinux-boot64.S
@@ -4,22 +4,52 @@
# BSD license as described in the LICENSE file in the top-level directory.
#include "processor-flags.h"
-#include "setup.S"
+
+#define BOOT_CR0 ( X86_CR0_PE \
+ | X86_CR0_WP \
+ | X86_CR0_PG )
+
+#define BOOT_CR4 ( X86_CR4_DE \
+ | X86_CR4_PSE \
+ | X86_CR4_PAE \
+ | X86_CR4_PGE \
+ | X86_CR4_PCE \
+ | X86_CR4_OSFXSR \
+ | X86_CR4_OSXMMEXCPT )
.text
.code64
.global vmlinux_entry64
vmlinux_entry64:
-# The address of boot_params structed is passed in RSI
-# register so pass it to extract_linux_boot_params fuction
-# which will extract cmdline and memory information and verify
-# that loader.elf was indeed called as Linux 64-bit vmlinux ELF
+ # The address of boot_params structed is passed in RSI
+ # register so pass it to extract_linux_boot_params fuction
+ # which will extract cmdline and memory information and verify
+ # that loader.elf was indeed called as Linux 64-bit vmlinux ELF
mov %rsi, %rdi
call extract_linux_boot_params
-# Even though we are in 64-bit long mode we need to reset
-# page tables and other CPU settings the way OSv expects it
- setup_64bit_long_mode
+ # Even though we are in 64-bit long mode we need to reset
+ # page tables and other CPU settings the way OSv expects it
+
+ # Enable PAE (Physical Address Extension) - ability to address 64GB
+ # TODO: Add more comments to processor-flags.h what each flag does
+ mov $BOOT_CR4, %rax
+ mov %rax, %cr4
+
+ # Set root of a page table in cr3
+ lea ident_pt_l4, %rax
+ mov %rax, %cr3
+
+ # Set long mode
+ mov $0xc0000080, %ecx // EFER MSR number
+ mov $0x00000900, %eax // Set LME = 1
+ xor %edx, %edx
+ wrmsr // Write contents of EDX:EAX (0:to Model Specific Register
specified by ECX register
+
+ # Activate paging and ...?
+ # TODO: Add more comments to processor-flags.h what each flag does
+ mov $BOOT_CR0, %rax
+ mov %rax, %cr0
mov $OSV_KERNEL_BASE, %rbp
mov $0x1000, %rbx
--
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