Commit ef9ab81a authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Dave Hansen
Browse files

x86/mm: Untangle __change_page_attr_set_clr(.checkalias) 



The .checkalias argument to __change_page_attr_set_clr() is overloaded
and serves two different purposes:

 - it inhibits the call to cpa_process_alias() -- as suggested by the
   name; however,

 - it also serves as 'primary' indicator for __change_page_attr()
   ( which in turn also serves as a recursion terminator for
     cpa_process_alias() ).

Untangle these by extending the use of CPA_NO_CHECK_ALIAS to all
callsites that currently use .checkalias=0 for this purpose.

Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20221110125544.527267183%40infradead.org
parent 5ceeee75

arch/x86/mm/pat/set_memory.c

+11 −19
Original line number Diff line number Diff line
@@ -1727,7 +1727,7 @@ static int __change_page_attr_set_clr(struct cpa_data *cpa, int checkalias) 
		if (ret)

			goto out;



		if (checkalias) {

		if (checkalias && !(cpa->flags & CPA_NO_CHECK_ALIAS)) {

			ret = cpa_process_alias(cpa);

			if (ret)

				goto out;
@@ -1801,18 +1801,12 @@ static int change_page_attr_set_clr(unsigned long *addr, int numpages, 
	cpa.numpages = numpages;

	cpa.mask_set = mask_set;

	cpa.mask_clr = mask_clr;

	cpa.flags = 0;

	cpa.flags = in_flag;

	cpa.curpage = 0;

	cpa.force_split = force_split;



	if (in_flag & (CPA_ARRAY | CPA_PAGES_ARRAY))

		cpa.flags |= in_flag;



	/* No alias checking for _NX bit modifications */

	checkalias = (pgprot_val(mask_set) | pgprot_val(mask_clr)) != _PAGE_NX;

	/* Has caller explicitly disabled alias checking? */

	if (in_flag & CPA_NO_CHECK_ALIAS)

		checkalias = 0;



	ret = __change_page_attr_set_clr(&cpa, checkalias);
@@ -2067,11 +2061,9 @@ int set_memory_np(unsigned long addr, int numpages) 


int set_memory_np_noalias(unsigned long addr, int numpages)

{

	int cpa_flags = CPA_NO_CHECK_ALIAS;



	return change_page_attr_set_clr(&addr, numpages, __pgprot(0),

					__pgprot(_PAGE_PRESENT), 0,

					cpa_flags, NULL);

					CPA_NO_CHECK_ALIAS, NULL);

}



int set_memory_4k(unsigned long addr, int numpages)
@@ -2288,7 +2280,7 @@ static int __set_pages_p(struct page *page, int numpages) 
				.numpages = numpages,

				.mask_set = __pgprot(_PAGE_PRESENT | _PAGE_RW),

				.mask_clr = __pgprot(0),

				.flags = 0};

				.flags = CPA_NO_CHECK_ALIAS };



	/*

	 * No alias checking needed for setting present flag. otherwise,
@@ -2296,7 +2288,7 @@ static int __set_pages_p(struct page *page, int numpages) 
	 * mappings (this adds to complexity if we want to do this from

	 * atomic context especially). Let's keep it simple!

	 */

	return __change_page_attr_set_clr(&cpa, 0);

	return __change_page_attr_set_clr(&cpa, 1);

}



static int __set_pages_np(struct page *page, int numpages)
@@ -2307,7 +2299,7 @@ static int __set_pages_np(struct page *page, int numpages) 
				.numpages = numpages,

				.mask_set = __pgprot(0),

				.mask_clr = __pgprot(_PAGE_PRESENT | _PAGE_RW),

				.flags = 0};

				.flags = CPA_NO_CHECK_ALIAS };



	/*

	 * No alias checking needed for setting not present flag. otherwise,
@@ -2315,7 +2307,7 @@ static int __set_pages_np(struct page *page, int numpages) 
	 * mappings (this adds to complexity if we want to do this from

	 * atomic context especially). Let's keep it simple!

	 */

	return __change_page_attr_set_clr(&cpa, 0);

	return __change_page_attr_set_clr(&cpa, 1);

}



int set_direct_map_invalid_noflush(struct page *page)
@@ -2386,7 +2378,7 @@ int __init kernel_map_pages_in_pgd(pgd_t *pgd, u64 pfn, unsigned long address, 
		.numpages = numpages,

		.mask_set = __pgprot(0),

		.mask_clr = __pgprot(~page_flags & (_PAGE_NX|_PAGE_RW)),

		.flags = 0,

		.flags = CPA_NO_CHECK_ALIAS,

	};



	WARN_ONCE(num_online_cpus() > 1, "Don't call after initializing SMP");
@@ -2399,7 +2391,7 @@ int __init kernel_map_pages_in_pgd(pgd_t *pgd, u64 pfn, unsigned long address, 


	cpa.mask_set = __pgprot(_PAGE_PRESENT | page_flags);



	retval = __change_page_attr_set_clr(&cpa, 0);

	retval = __change_page_attr_set_clr(&cpa, 1);

	__flush_tlb_all();



out:
@@ -2429,12 +2421,12 @@ int __init kernel_unmap_pages_in_pgd(pgd_t *pgd, unsigned long address, 
		.numpages	= numpages,

		.mask_set	= __pgprot(0),

		.mask_clr	= __pgprot(_PAGE_PRESENT | _PAGE_RW),

		.flags		= 0,

		.flags		= CPA_NO_CHECK_ALIAS,

	};



	WARN_ONCE(num_online_cpus() > 1, "Don't call after initializing SMP");



	retval = __change_page_attr_set_clr(&cpa, 0);

	retval = __change_page_attr_set_clr(&cpa, 1);

	__flush_tlb_all();



	return retval;