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author | Michael Ellerman <mpe@ellerman.id.au> | 2017-07-14 16:51:23 +1000 |
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committer | Michael Ellerman <mpe@ellerman.id.au> | 2017-07-18 19:54:24 +1000 |
commit | 029d9252b116fa52a95150819e62af1f6e420fe5 (patch) | |
tree | 6f7832ca67de31a117dbb1b3346bfae3ec1a348e /arch/powerpc/mm | |
parent | fa7f9189e017213bad63b93a76de5c715cd62a96 (diff) | |
download | linux-stable-029d9252b116fa52a95150819e62af1f6e420fe5.tar.gz linux-stable-029d9252b116fa52a95150819e62af1f6e420fe5.tar.bz2 linux-stable-029d9252b116fa52a95150819e62af1f6e420fe5.zip |
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.c | 1 | ||||
-rw-r--r-- | arch/powerpc/mm/pgtable-hash64.c | 12 | ||||
-rw-r--r-- | arch/powerpc/mm/pgtable-radix.c | 8 | ||||
-rw-r--r-- | arch/powerpc/mm/pgtable_64.c | 8 |
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 |