On Tue, Jan 31, 2023 at 10:58:56AM +0000, Christophe Leroy wrote:

Le 31/01/2023 à 10:09, Peter Zijlstra a écrit :

quoted

quoted

@@ -573,23 +574,33 @@ bool __is_module_percpu_address(unsigned long addr, unsigned long *can_addr);
  bool is_module_percpu_address(unsigned long addr);
  bool is_module_text_address(unsigned long addr);
  
+static inline bool within_module_mem_type(unsigned long addr,
+					  const struct module *mod,
+					  enum mod_mem_type type)
+{
+	unsigned long base, size;
+
+	base = (unsigned long)mod->mem[type].base;
+	size = mod->mem[type].size;
+
+	return base <= addr && addr < base + size;

Possible (as inspired by all the above is_{init,core}() etc..

	return addr - base < size;

In kernel/module/main.c we have a function called within(). Maybe that 
function could be lifted in module.h and used.

More sharing more good. But I don't think we can lift a 'within'
function to the global namespace, that's just asking for pain.

quoted

static inline bool within_module_mem_types(unsigned long addr,
					   const struct module *mod,
					   enum mod_mem_type first,
					   enum mod_mem_type last)
{
	for (enum mod_mem_type type = first; type <= last; type++) {
		if (within_module_mem_type(addr, mod, type))
			return true;
	}
	return false;
}

Well, ok but what garanties it will always be contiguous types ?
And you can't anymore see at first look what types it is.

I prefer it to be explicit with within_module_mem_type(TYPE1) || 
within_module_mem_type(TYPE2) || within_module_mem_type(TYPE3). By the 
way we could make the function name shorter, even within() may be a 
better name as it is used only inside module code.

Something like

	return within(addr, mod, MOD_TEXT) || within(addr, mod, MOD_DATA) ||
	       within(addr, mod, MOD_RODATA) || within(addr, mod, 
MOD_RO_AFTER_INIT);

Urgh, how about?

	for_each_mod_mem_type(type) {
		if (!mod_mem_type_is_init(type) && within(addr, mod, type))
			return true;
	}
	return false;

Then you have have a bunch of mod_mem_type_id_foo() filter functions
that are non-contiguous without having to endlessly repeat stuff
manually.