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Subject[PATCH 27/39] x86/mm/pti: Make pti_clone_kernel_text() compile on 32 bit
Date
From: Joerg Roedel <jroedel@suse.de>

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 we need a symbol 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>
---
arch/x86/include/asm/sections.h | 1 +
arch/x86/kernel/vmlinux.lds.S | 17 ++++++++++-------
arch/x86/mm/pti.c | 2 +-
3 files changed, 12 insertions(+), 8 deletions(-)

diff --git a/arch/x86/include/asm/sections.h b/arch/x86/include/asm/sections.h
index 5c019d2..4a911a3 100644
--- a/arch/x86/include/asm/sections.h
+++ b/arch/x86/include/asm/sections.h
@@ -7,6 +7,7 @@

extern char __brk_base[], __brk_limit[];
extern struct exception_table_entry __stop___ex_table[];
+extern char __end_rodata_aligned[];

#if defined(CONFIG_X86_64)
extern char __end_rodata_hpage_align[];
diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S
index 5e1458f..8bde0a4 100644
--- a/arch/x86/kernel/vmlinux.lds.S
+++ b/arch/x86/kernel/vmlinux.lds.S
@@ -55,19 +55,22 @@ jiffies_64 = jiffies;
* so we can enable protection checks as well as retain 2MB large page
* 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); \
- __end_rodata_hpage_align = .;
+ __end_rodata_hpage_align = .; \
+ __end_rodata_aligned = .;

#define ALIGN_ENTRY_TEXT_BEGIN . = ALIGN(PMD_SIZE);
#define ALIGN_ENTRY_TEXT_END . = ALIGN(PMD_SIZE);

#else

-#define X64_ALIGN_RODATA_BEGIN
-#define X64_ALIGN_RODATA_END
+#define X86_ALIGN_RODATA_BEGIN
+#define X86_ALIGN_RODATA_END \
+ . = ALIGN(PAGE_SIZE); \
+ __end_rodata_aligned = .;

#define ALIGN_ENTRY_TEXT_BEGIN
#define ALIGN_ENTRY_TEXT_END
@@ -141,9 +144,9 @@ SECTIONS

/* .text should occupy whole number of pages */
. = ALIGN(PAGE_SIZE);
- X64_ALIGN_RODATA_BEGIN
+ X86_ALIGN_RODATA_BEGIN
RO_DATA(PAGE_SIZE)
- X64_ALIGN_RODATA_END
+ X86_ALIGN_RODATA_END

/* Data */
.data : AT(ADDR(.data) - LOAD_OFFSET) {
diff --git a/arch/x86/mm/pti.c b/arch/x86/mm/pti.c
index 2eadab0..4f6e933 100644
--- a/arch/x86/mm/pti.c
+++ b/arch/x86/mm/pti.c
@@ -470,7 +470,7 @@ void pti_clone_kernel_text(void)
* clone the areas past rodata, they might contain secrets.
*/
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())
return;
--
2.7.4
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