execmem: drop unused execmem_update_copy()

Patch series "x86: enable EXECMEM_ROX_CACHE for ftrace and kprobes", v3.

These patches enable use of EXECMEM_ROX_CACHE for ftrace and kprobes
allocations on x86.

They also include some ground work in execmem.

Since the execmem model for caching large ROX pages changed from the
initial assumption that the memory that is allocated from ROX cache is
always ROX to the current state where memory can be temporarily made RW
and then restored to ROX, we can stop using text poking to update it.
This also saves the hassle of trying lock text_mutex in
execmem_cache_free() when kprobes already hold that mutex.

This patch (of 8):

The execmem_update_copy() that used text poking was required when memory
allocated from ROX cache was always read-only.  Since now its permissions
can be switched to read-write there is no need in a function that updates
memory with text poking.

Remove it.

Link: https://lkml.kernel.org/r/20250713071730.4117334-1-rppt@kernel.org
Link: https://lkml.kernel.org/r/20250713071730.4117334-2-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>

diff --git a/include/linux/execmem.h b/include/linux/execmem.h
index 3be35680a54fd1666e2db60a667b72efbe331e12..734fbe83d98e6948d5e1c2feb1619bcfbf4f2a49 100644 (file)
--- a/include/linux/execmem.h
+++ b/include/linux/execmem.h
@@ -185,19 +185,6 @@ DEFINE_FREE(execmem, void *, if (_T) execmem_free(_T));
 struct vm_struct *execmem_vmap(size_t size);
 #endif
 
-/**
- * execmem_update_copy - copy an update to executable memory
- * @dst:  destination address to update
- * @src:  source address containing the data
- * @size: how many bytes of memory shold be copied
- *
- * Copy @size bytes from @src to @dst using text poking if the memory at
- * @dst is read-only.
- *
- * Return: a pointer to @dst or NULL on error
- */
-void *execmem_update_copy(void *dst, const void *src, size_t size);
-
 /**
  * execmem_is_rox - check if execmem is read-only
  * @type - the execmem type to check

diff --git a/mm/execmem.c b/mm/execmem.c
index 627e6cf64f4ff5f3fdcfc0f585f7fc7d8b83dbc8..aac211bc88c570398cb242e18e6728337ab5a3e7 100644 (file)
--- a/mm/execmem.c
+++ b/mm/execmem.c
@@ -399,11 +399,6 @@ void execmem_free(void *ptr)
                vfree(ptr);
 }
 
-void *execmem_update_copy(void *dst, const void *src, size_t size)
-{
-       return text_poke_copy(dst, src, size);
-}
-
 bool execmem_is_rox(enum execmem_type type)
 {
        return !!(execmem_info->ranges[type].flags & EXECMEM_ROX_CACHE);