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execmem: drop writable parameter from execmem_fill_trapping_insns() 

After update of execmem_cache_free() that made memory writable before
updating it, there is no need to update read only memory, so the writable
parameter to execmem_fill_trapping_insns() is not needed.  Drop it.

Link: https://lkml.kernel.org/r/20250713071730.4117334-7-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Daniel Gomez <da.gomez@samsung.com>
Cc: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Cc: Petr Pavlu <petr.pavlu@suse.com>
Cc: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
pull/1314/head
Mike Rapoport (Microsoft) 2025-07-13 10:17:28 +03:00 committed by Andrew Morton
parent 3bd4e0ac61
commit ab674b6871
3 changed files with 5 additions and 10 deletions
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8
arch/x86/mm/init.c
View File

@ -1063,13 +1063,9 @@ unsigned long arch_max_swapfile_size(void)
static struct execmem_info execmem_info __ro_after_init;
#ifdef CONFIG_ARCH_HAS_EXECMEM_ROX
void execmem_fill_trapping_insns(void *ptr, size_t size, bool writeable)
void execmem_fill_trapping_insns(void *ptr, size_t size)
{
/* fill memory with INT3 instructions */
if (writeable)
memset(ptr, INT3_INSN_OPCODE, size);
else
text_poke_set(ptr, INT3_INSN_OPCODE, size);
memset(ptr, INT3_INSN_OPCODE, size);
}
#endif

3
include/linux/execmem.h
View File

@ -60,12 +60,11 @@ enum execmem_range_flags {
* will trap
* @ptr: pointer to memory to fill
* @size: size of the range to fill
* @writable: is the memory poited by @ptr is writable or ROX
*
* A hook for architecures to fill execmem ranges with invalid instructions.
* Architectures that use EXECMEM_ROX_CACHE must implement this.
*/
void execmem_fill_trapping_insns(void *ptr, size_t size, bool writable);
void execmem_fill_trapping_insns(void *ptr, size_t size);
/**
* execmem_restore_rox - restore read-only-execute permissions

4
mm/execmem.c
View File

@ -304,7 +304,7 @@ static int execmem_cache_populate(struct execmem_range *range, size_t size)
goto err_free_mem;
/* fill memory with instructions that will trap */
execmem_fill_trapping_insns(p, alloc_size, /* writable = */ true);
execmem_fill_trapping_insns(p, alloc_size);
err = set_memory_rox((unsigned long)p, vm->nr_pages);
if (err)
@ -363,7 +363,7 @@ static int __execmem_cache_free(struct ma_state *mas, void *ptr, gfp_t gfp_mask)
if (err)
return err;
execmem_fill_trapping_insns(ptr, size, /* writable = */ true);
execmem_fill_trapping_insns(ptr, size);
execmem_restore_rox(ptr, size);
err = execmem_cache_add_locked(ptr, size, gfp_mask);