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authorChristophe Leroy <christophe.leroy@c-s.fr>2017-08-02 15:51:05 +0200
committerMichael Ellerman <mpe@ellerman.id.au>2017-08-15 14:55:57 +0200
commit95902e6c8864d39b09134dcaa3c99d8161d1deea (patch)
treecb41417a8e6436b46a3b504fe73641b4234d5262 /arch/powerpc/mm/pgtable_32.c
parentpowerpc/mm: Fix kernel RAM protection after freeing unused memory on PPC32 (diff)
downloadlinux-95902e6c8864d39b09134dcaa3c99d8161d1deea.tar.xz
linux-95902e6c8864d39b09134dcaa3c99d8161d1deea.zip
powerpc/mm: Implement STRICT_KERNEL_RWX on PPC32
This patch implements STRICT_KERNEL_RWX on PPC32. As for CONFIG_DEBUG_PAGEALLOC, it deactivates BAT and LTLB mappings in order to allow page protection setup at the level of each page. As BAT/LTLB mappings are deactivated, there might be a performance impact. Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch/powerpc/mm/pgtable_32.c')
-rw-r--r--arch/powerpc/mm/pgtable_32.c24
1 files changed, 24 insertions, 0 deletions
diff --git a/arch/powerpc/mm/pgtable_32.c b/arch/powerpc/mm/pgtable_32.c
index 85e8f0e0efe6..4a3dd9fc6989 100644
--- a/arch/powerpc/mm/pgtable_32.c
+++ b/arch/powerpc/mm/pgtable_32.c
@@ -34,6 +34,7 @@
#include <asm/fixmap.h>
#include <asm/io.h>
#include <asm/setup.h>
+#include <asm/sections.h>
#include "mmu_decl.h"
@@ -375,6 +376,29 @@ void mark_initmem_nx(void)
change_page_attr(page, numpages, PAGE_KERNEL);
}
+#ifdef CONFIG_STRICT_KERNEL_RWX
+void mark_rodata_ro(void)
+{
+ struct page *page;
+ unsigned long numpages;
+
+ page = virt_to_page(_stext);
+ numpages = PFN_UP((unsigned long)_etext) -
+ PFN_DOWN((unsigned long)_stext);
+
+ change_page_attr(page, numpages, PAGE_KERNEL_ROX);
+ /*
+ * mark .rodata as read only. Use __init_begin rather than __end_rodata
+ * to cover NOTES and EXCEPTION_TABLE.
+ */
+ page = virt_to_page(__start_rodata);
+ numpages = PFN_UP((unsigned long)__init_begin) -
+ PFN_DOWN((unsigned long)__start_rodata);
+
+ change_page_attr(page, numpages, PAGE_KERNEL_RO);
+}
+#endif
+
#ifdef CONFIG_DEBUG_PAGEALLOC
void __kernel_map_pages(struct page *page, int numpages, int enable)
{