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x86/mm/pti: Make pti_clone_kernel_text() compile on 32 bit

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The pti_clone_kernel_text() function references __end_rodata_hpage_align,
which is only present on x86-64.  This makes sense as the end of the rodata
section is not huge-page aligned on 32 bit.

Nevertheless a symbol is required for the function that points at the right
address for both 32 and 64 bit. Introduce __end_rodata_aligned for that
purpose and use it in pti_clone_kernel_text().

Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Pavel Machek <pavel@ucw.cz>
Cc: "H . Peter Anvin" <hpa@zytor.com>
Cc: linux-mm@kvack.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: David Laight <David.Laight@aculab.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Eduardo Valentin <eduval@amazon.com>
Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: aliguori@amazon.com
Cc: daniel.gruss@iaik.tugraz.at
Cc: hughd@google.com
Cc: keescook@google.com
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Waiman Long <llong@redhat.com>
Cc: "David H . Gutteridge" <dhgutteridge@sympatico.ca>
Cc: joro@8bytes.org
Link: https://lkml.kernel.org/r/1531906876-13451-28-git-send-email-joro@8bytes.org
This commit is contained in:
Joerg Roedel 2018-07-18 11:41:04 +02:00 committed by Thomas Gleixner
parent f94560cd6b
commit 39d668e04e
3 changed files with 12 additions and 8 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

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

@ -7,6 +7,7 @@
extern char __brk_base[], __brk_limit[]; extern char __brk_base[], __brk_limit[];
extern struct exception_table_entry __stop___ex_table[]; extern struct exception_table_entry __stop___ex_table[];
extern char __end_rodata_aligned[];
#if defined(CONFIG_X86_64) #if defined(CONFIG_X86_64)
extern char __end_rodata_hpage_align[]; extern char __end_rodata_hpage_align[];

17
arch/x86/kernel/vmlinux.lds.S
View file

@ -55,19 +55,22 @@ jiffies_64 = jiffies;
* so we can enable protection checks as well as retain 2MB large page * so we can enable protection checks as well as retain 2MB large page
* mappings for kernel text. * mappings for kernel text.
*/ */
#define X64_ALIGN_RODATA_BEGIN . = ALIGN(HPAGE_SIZE); #define X86_ALIGN_RODATA_BEGIN . = ALIGN(HPAGE_SIZE);
#define X64_ALIGN_RODATA_END \ #define X86_ALIGN_RODATA_END \
. = ALIGN(HPAGE_SIZE); \ . = ALIGN(HPAGE_SIZE); \
__end_rodata_hpage_align = .; __end_rodata_hpage_align = .; \
__end_rodata_aligned = .;
#define ALIGN_ENTRY_TEXT_BEGIN . = ALIGN(PMD_SIZE); #define ALIGN_ENTRY_TEXT_BEGIN . = ALIGN(PMD_SIZE);
#define ALIGN_ENTRY_TEXT_END . = ALIGN(PMD_SIZE); #define ALIGN_ENTRY_TEXT_END . = ALIGN(PMD_SIZE);
#else #else
#define X64_ALIGN_RODATA_BEGIN #define X86_ALIGN_RODATA_BEGIN
#define X64_ALIGN_RODATA_END #define X86_ALIGN_RODATA_END \
. = ALIGN(PAGE_SIZE); \
__end_rodata_aligned = .;
#define ALIGN_ENTRY_TEXT_BEGIN #define ALIGN_ENTRY_TEXT_BEGIN
#define ALIGN_ENTRY_TEXT_END #define ALIGN_ENTRY_TEXT_END
@ -141,9 +144,9 @@ SECTIONS
/* .text should occupy whole number of pages */ /* .text should occupy whole number of pages */
. = ALIGN(PAGE_SIZE); . = ALIGN(PAGE_SIZE);
X64_ALIGN_RODATA_BEGIN X86_ALIGN_RODATA_BEGIN
RO_DATA(PAGE_SIZE) RO_DATA(PAGE_SIZE)
X64_ALIGN_RODATA_END X86_ALIGN_RODATA_END
/* Data */ /* Data */
.data : AT(ADDR(.data) - LOAD_OFFSET) { .data : AT(ADDR(.data) - LOAD_OFFSET) {

2
arch/x86/mm/pti.c
View file

@ -470,7 +470,7 @@ void pti_clone_kernel_text(void)
* clone the areas past rodata, they might contain secrets. * clone the areas past rodata, they might contain secrets.
*/ */
unsigned long start = PFN_ALIGN(_text); unsigned long start = PFN_ALIGN(_text);
unsigned long end = (unsigned long)__end_rodata_hpage_align; unsigned long end = (unsigned long)__end_rodata_aligned;
if (!pti_kernel_image_global_ok()) if (!pti_kernel_image_global_ok())
return; return;