Kernel/linux-next
1
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git synced 2025-01-15 21:23:23 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

x86/kexec: Move relocate_kernel to kernel .data section

Browse Source 
Now that the copy is executed instead of the original, the relocate_kernel
page can live in the kernel's .text section. This will allow subsequent
commits to actually add real data to it and clean up the code somewhat as
well as making the control page ROX.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Baoquan He <bhe@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Link: https://lore.kernel.org/r/20241205153343.3275139-9-dwmw2@infradead.org
This commit is contained in:
David Woodhouse 2024-12-05 15:05:14 +00:00 committed by Ingo Molnar
parent eeebbde571
commit cb33ff9e06
5 changed files with 24 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
arch/x86/include/asm/sections.h
View File

@ -5,6 +5,7 @@
#include <asm-generic/sections.h>
#include <asm/extable.h>
extern char __relocate_kernel_start[], __relocate_kernel_end[];
extern char __brk_base[], __brk_limit[];
extern char __end_rodata_aligned[];

6
arch/x86/kernel/callthunks.c
View File

@ -139,9 +139,15 @@ static bool skip_addr(void *dest)
return true;
#endif
#ifdef CONFIG_KEXEC_CORE
# ifdef CONFIG_X86_64
if (dest >= (void *)__relocate_kernel_start &&
dest < (void *)__relocate_kernel_end)
return true;
# else
if (dest >= (void *)relocate_kernel &&
dest < (void*)relocate_kernel + KEXEC_CONTROL_CODE_MAX_SIZE)
return true;
# endif
#endif
#ifdef CONFIG_XEN
if (dest >= (void *)hypercall_page &&

4
arch/x86/kernel/machine_kexec_64.c
View File

@ -307,6 +307,8 @@ static void load_segments(void)
int machine_kexec_prepare(struct kimage *image)
{
void *control_page = page_address(image->control_code_page);
unsigned long reloc_start = (unsigned long)__relocate_kernel_start;
unsigned long reloc_end = (unsigned long)__relocate_kernel_end;
int result;
/* Setup the identity mapped 64bit page table */
@ -314,7 +316,7 @@ int machine_kexec_prepare(struct kimage *image)
if (result)
return result;
__memcpy(control_page, relocate_kernel, KEXEC_CONTROL_CODE_MAX_SIZE);
__memcpy(control_page, __relocate_kernel_start, reloc_end - reloc_start);
set_memory_x((unsigned long)control_page, 1);

7
arch/x86/kernel/relocate_kernel_64.S
View File

@ -41,10 +41,8 @@
#define CP_PA_BACKUP_PAGES_MAP DATA(0x30)
#define CP_VA_CONTROL_PAGE DATA(0x38)
.text
.align PAGE_SIZE
.section .text.relocate_kernel,"ax";
.code64
SYM_CODE_START_NOALIGN(relocate_range)
SYM_CODE_START_NOALIGN(relocate_kernel)
UNWIND_HINT_END_OF_STACK
ANNOTATE_NOENDBR
@ -341,6 +339,3 @@ SYM_CODE_START_LOCAL_NOALIGN(swap_pages)
ret
int3
SYM_CODE_END(swap_pages)
.skip KEXEC_CONTROL_CODE_MAX_SIZE - (. - relocate_kernel), 0xcc
SYM_CODE_END(relocate_range);

13
arch/x86/kernel/vmlinux.lds.S
View File

@ -28,6 +28,7 @@
#include <asm/orc_lookup.h>
#include <asm/cache.h>
#include <asm/boot.h>
#include <asm/kexec.h>
#undef i386 /* in case the preprocessor is a 32bit one */
@ -95,7 +96,18 @@ const_pcpu_hot = pcpu_hot;
#define BSS_DECRYPTED
#endif
#if defined(CONFIG_X86_64) && defined(CONFIG_KEXEC_CORE)
#define KEXEC_RELOCATE_KERNEL \
. = ALIGN(0x100); \
__relocate_kernel_start = .; \
*(.text.relocate_kernel); \
__relocate_kernel_end = .;
ASSERT(__relocate_kernel_end - __relocate_kernel_start <= KEXEC_CONTROL_CODE_MAX_SIZE,
"relocate_kernel code too large!")
#else
#define KEXEC_RELOCATE_KERNEL
#endif
PHDRS {
text PT_LOAD FLAGS(5); /* R_E */
data PT_LOAD FLAGS(6); /* RW_ */
@ -184,6 +196,7 @@ SECTIONS
DATA_DATA
CONSTRUCTORS
KEXEC_RELOCATE_KERNEL
/* rarely changed data like cpu maps */
READ_MOSTLY_DATA(INTERNODE_CACHE_BYTES)