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authorMichael Ellerman <mpe@ellerman.id.au>2017-07-14 09:51:23 +0300
committerMichael Ellerman <mpe@ellerman.id.au>2017-07-18 12:54:24 +0300
commit029d9252b116fa52a95150819e62af1f6e420fe5 (patch)
tree6f7832ca67de31a117dbb1b3346bfae3ec1a348e /arch/powerpc/mm
parentfa7f9189e017213bad63b93a76de5c715cd62a96 (diff)
downloadlinux-029d9252b116fa52a95150819e62af1f6e420fe5.tar.xz
powerpc/mm: Mark __init memory no-execute when STRICT_KERNEL_RWX=y
Currently even with STRICT_KERNEL_RWX we leave the __init text marked executable after init, which is bad. Add a hook to mark it NX (no-execute) before we free it, and implement it for radix and hash. Note that we use __init_end as the end address, not _einittext, because overlaps_kernel_text() uses __init_end, because there are additional executable sections other than .init.text between __init_begin and __init_end. Tested on radix and hash with: 0:mon> p $__init_begin *** 400 exception occurred Fixes: 1e0fc9d1eb2b ("powerpc/Kconfig: Enable STRICT_KERNEL_RWX for some configs") Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch/powerpc/mm')
-rw-r--r--arch/powerpc/mm/mem.c1
-rw-r--r--arch/powerpc/mm/pgtable-hash64.c12
-rw-r--r--arch/powerpc/mm/pgtable-radix.c8
-rw-r--r--arch/powerpc/mm/pgtable_64.c8
4 files changed, 29 insertions, 0 deletions
diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c
index 8541f18694a4..46b4e67d2372 100644
--- a/arch/powerpc/mm/mem.c
+++ b/arch/powerpc/mm/mem.c
@@ -402,6 +402,7 @@ void __init mem_init(void)
void free_initmem(void)
{
ppc_md.progress = ppc_printk_progress;
+ mark_initmem_nx();
free_initmem_default(POISON_FREE_INITMEM);
}
diff --git a/arch/powerpc/mm/pgtable-hash64.c b/arch/powerpc/mm/pgtable-hash64.c
index 73019c52141f..443a2c66a304 100644
--- a/arch/powerpc/mm/pgtable-hash64.c
+++ b/arch/powerpc/mm/pgtable-hash64.c
@@ -460,4 +460,16 @@ void hash__mark_rodata_ro(void)
WARN_ON(!hash__change_memory_range(start, end, PP_RXXX));
}
+
+void hash__mark_initmem_nx(void)
+{
+ unsigned long start, end, pp;
+
+ start = (unsigned long)__init_begin;
+ end = (unsigned long)__init_end;
+
+ pp = htab_convert_pte_flags(pgprot_val(PAGE_KERNEL));
+
+ WARN_ON(!hash__change_memory_range(start, end, pp));
+}
#endif
diff --git a/arch/powerpc/mm/pgtable-radix.c b/arch/powerpc/mm/pgtable-radix.c
index 336e52ec652c..5cc50d47ce3f 100644
--- a/arch/powerpc/mm/pgtable-radix.c
+++ b/arch/powerpc/mm/pgtable-radix.c
@@ -162,6 +162,14 @@ void radix__mark_rodata_ro(void)
radix__change_memory_range(start, end, _PAGE_WRITE);
}
+
+void radix__mark_initmem_nx(void)
+{
+ unsigned long start = (unsigned long)__init_begin;
+ unsigned long end = (unsigned long)__init_end;
+
+ radix__change_memory_range(start, end, _PAGE_EXEC);
+}
#endif /* CONFIG_STRICT_KERNEL_RWX */
static inline void __meminit print_mapping(unsigned long start,
diff --git a/arch/powerpc/mm/pgtable_64.c b/arch/powerpc/mm/pgtable_64.c
index 5c0b795d656c..0736e94c7615 100644
--- a/arch/powerpc/mm/pgtable_64.c
+++ b/arch/powerpc/mm/pgtable_64.c
@@ -505,4 +505,12 @@ void mark_rodata_ro(void)
else
hash__mark_rodata_ro();
}
+
+void mark_initmem_nx(void)
+{
+ if (radix_enabled())
+ radix__mark_initmem_nx();
+ else
+ hash__mark_initmem_nx();
+}
#endif