From: Balbir Singh <bsinghar...@gmail.com>
With hash we update the bolted pte to mark it read-only. We rely
on the MMU_FTR_KERNEL_RO to generate the correct permissions
for read-only text. The radix implementation just prints a warning
in this implementation
Signed-off-by: Balbir Singh <bsinghar...@gmail.com>
Signed-off-by: Michael Ellerman <m...@ellerman.id.au>
---
arch/powerpc/include/asm/book3s/64/hash.h | 3 +++
arch/powerpc/include/asm/book3s/64/radix.h | 4 +++
arch/powerpc/mm/pgtable-hash64.c | 41 ++++++++++++++++++++++++++++++
arch/powerpc/mm/pgtable-radix.c | 7 +++++
arch/powerpc/mm/pgtable_64.c | 9 +++++++
5 files changed, 64 insertions(+)
diff --git a/arch/powerpc/include/asm/book3s/64/hash.h
b/arch/powerpc/include/asm/book3s/64/hash.h
index 4e957b027fe0..0ce513f2926f 100644
--- a/arch/powerpc/include/asm/book3s/64/hash.h
+++ b/arch/powerpc/include/asm/book3s/64/hash.h
@@ -89,6 +89,9 @@ static inline int hash__pgd_bad(pgd_t pgd)
{
return (pgd_val(pgd) == 0);
}
+#ifdef CONFIG_STRICT_KERNEL_RWX
+extern void hash__mark_rodata_ro(void);
+#endif
extern void hpte_need_flush(struct mm_struct *mm, unsigned long addr,
pte_t *ptep, unsigned long pte, int huge);
diff --git a/arch/powerpc/include/asm/book3s/64/radix.h
b/arch/powerpc/include/asm/book3s/64/radix.h
index ba43754e96d2..487709ff6875 100644
--- a/arch/powerpc/include/asm/book3s/64/radix.h
+++ b/arch/powerpc/include/asm/book3s/64/radix.h
@@ -116,6 +116,10 @@
#define RADIX_PUD_TABLE_SIZE (sizeof(pud_t) << RADIX_PUD_INDEX_SIZE)
#define RADIX_PGD_TABLE_SIZE (sizeof(pgd_t) << RADIX_PGD_INDEX_SIZE)
+#ifdef CONFIG_STRICT_KERNEL_RWX
+extern void radix__mark_rodata_ro(void);
+#endif
+
static inline unsigned long __radix_pte_update(pte_t *ptep, unsigned long clr,
unsigned long set)
{
diff --git a/arch/powerpc/mm/pgtable-hash64.c b/arch/powerpc/mm/pgtable-hash64.c
index a0facee58811..0809102b66bd 100644
--- a/arch/powerpc/mm/pgtable-hash64.c
+++ b/arch/powerpc/mm/pgtable-hash64.c
@@ -11,8 +11,12 @@
#include <linux/sched.h>
#include <linux/mm_types.h>
+#include <linux/mm.h>
#include <asm/pgalloc.h>
+#include <asm/pgtable.h>
+#include <asm/sections.h>
+#include <asm/mmu.h>
#include <asm/tlb.h>
#include "mmu_decl.h"
@@ -419,3 +423,40 @@ int hash__has_transparent_hugepage(void)
return 1;
}
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
+
+#ifdef CONFIG_STRICT_KERNEL_RWX
+void hash__mark_rodata_ro(void)
+{
+ unsigned long start = (unsigned long)_stext;
+ unsigned long end = (unsigned long)__init_begin;
+ unsigned long idx;
+ unsigned int step, shift;
+ unsigned long newpp = PP_RXXX;
+
+ if (!mmu_has_feature(MMU_FTR_KERNEL_RO)) {
+ pr_info("R/O rodata not supported\n");
+ return;
+ }
+
+ shift = mmu_psize_defs[mmu_linear_psize].shift;
+ step = 1 << shift;
+
+ start = ((start + step - 1) >> shift) << shift;
+ end = (end >> shift) << shift;
+
+ pr_devel("marking ro start %lx, end %lx, step %x\n",
+ start, end, step);
+
+ if (start == end) {
+ pr_warn("could not set rodata ro, relocate the start"
+ " of the kernel to a 0x%x boundary\n", step);
+ return;
+ }
+
+ for (idx = start; idx < end; idx += step)
+ /* Not sure if we can do much with the return value */
+ mmu_hash_ops.hpte_updateboltedpp(newpp, idx, mmu_linear_psize,
+ mmu_kernel_ssize);
+
+}
+#endif
diff --git a/arch/powerpc/mm/pgtable-radix.c b/arch/powerpc/mm/pgtable-radix.c
index 1342859552b1..b07e0008d02a 100644
--- a/arch/powerpc/mm/pgtable-radix.c
+++ b/arch/powerpc/mm/pgtable-radix.c
@@ -110,6 +110,13 @@ int radix__map_kernel_page(unsigned long ea, unsigned long
pa,
return 0;
}
+#ifdef CONFIG_STRICT_KERNEL_RWX
+void radix__mark_rodata_ro(void)
+{
+ pr_warn("Not yet implemented for radix\n");
+}
+#endif
+
static inline void __meminit print_mapping(unsigned long start,
unsigned long end,
unsigned long size)
diff --git a/arch/powerpc/mm/pgtable_64.c b/arch/powerpc/mm/pgtable_64.c
index bce0ed50789c..5b0c2d63d645 100644
--- a/arch/powerpc/mm/pgtable_64.c
+++ b/arch/powerpc/mm/pgtable_64.c
@@ -491,3 +491,12 @@ void mmu_partition_table_set_entry(unsigned int lpid,
unsigned long dw0,
}
EXPORT_SYMBOL_GPL(mmu_partition_table_set_entry);
#endif /* CONFIG_PPC_BOOK3S_64 */
+
+#ifdef CONFIG_STRICT_KERNEL_RWX
+void mark_rodata_ro(void)
+{
+ if (radix_enabled())
+ return radix__mark_rodata_ro();
+ return hash__mark_rodata_ro();
+}
+#endif
--
2.7.4
