diff options
| author | Peter Zijlstra <peterz@infradead.org> | 2025-04-23 16:30:11 +0200 |
|---|---|---|
| committer | Dave Hansen <dave.hansen@linux.intel.com> | 2025-05-09 13:33:20 -0700 |
| commit | d6d1e3e6580ca35071ad474381f053cbf1fb6414 (patch) | |
| tree | 3f7e32bd070bdc785a93423464a03c7f5a0cc11b /mm/execmem.c | |
| parent | f0cd7091cc5a032c8870b4285305d9172569d126 (diff) | |
mm/execmem: Unify early execmem_cache behaviour
Early kernel memory is RWX, only at the end of early boot (before SMP)
do we mark things ROX. Have execmem_cache mirror this behaviour for
early users.
This avoids having to remember what code is execmem and what is not --
we can poke everything with impunity ;-) Also performance for not
having to do endless text_poke_mm switches.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Diffstat (limited to 'mm/execmem.c')
| -rw-r--r-- | mm/execmem.c | 40 |
1 files changed, 37 insertions, 3 deletions
diff --git a/mm/execmem.c b/mm/execmem.c index e6c4f5076ca8..6f7a2653b280 100644 --- a/mm/execmem.c +++ b/mm/execmem.c @@ -254,6 +254,34 @@ out_unlock: return ptr; } +static bool execmem_cache_rox = false; + +void execmem_cache_make_ro(void) +{ + struct maple_tree *free_areas = &execmem_cache.free_areas; + struct maple_tree *busy_areas = &execmem_cache.busy_areas; + MA_STATE(mas_free, free_areas, 0, ULONG_MAX); + MA_STATE(mas_busy, busy_areas, 0, ULONG_MAX); + struct mutex *mutex = &execmem_cache.mutex; + void *area; + + execmem_cache_rox = true; + + mutex_lock(mutex); + + mas_for_each(&mas_free, area, ULONG_MAX) { + unsigned long pages = mas_range_len(&mas_free) >> PAGE_SHIFT; + set_memory_ro(mas_free.index, pages); + } + + mas_for_each(&mas_busy, area, ULONG_MAX) { + unsigned long pages = mas_range_len(&mas_busy) >> PAGE_SHIFT; + set_memory_ro(mas_busy.index, pages); + } + + mutex_unlock(mutex); +} + static int execmem_cache_populate(struct execmem_range *range, size_t size) { unsigned long vm_flags = VM_ALLOW_HUGE_VMAP; @@ -274,9 +302,15 @@ static int execmem_cache_populate(struct execmem_range *range, size_t size) /* fill memory with instructions that will trap */ execmem_fill_trapping_insns(p, alloc_size, /* writable = */ true); - err = set_memory_rox((unsigned long)p, vm->nr_pages); - if (err) - goto err_free_mem; + if (execmem_cache_rox) { + err = set_memory_rox((unsigned long)p, vm->nr_pages); + if (err) + goto err_free_mem; + } else { + err = set_memory_x((unsigned long)p, vm->nr_pages); + if (err) + goto err_free_mem; + } err = execmem_cache_add(p, alloc_size); if (err) |