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Subject[RFC][PATCH 08/10] x86/mm/cpa: Fold cpa_flush_range() and cpa_flush_array()
Note that the cache flush loop in cpa_flush_*() is identical when we
use __cpa_addr(); further observe that flush_tlb_kernel_range() is a
special case of to the cpa_flush_array() TLB invalidation code.

This then means the two functions are virtually identical. Fold these
two functions into a single cpa_flush() call.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
arch/x86/mm/pageattr.c | 92 +++++++++----------------------------------------
1 file changed, 18 insertions(+), 74 deletions(-)

--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -304,51 +304,7 @@ static void cpa_flush_all(unsigned long
on_each_cpu(__cpa_flush_all, (void *) cache, 1);
}

-static bool __inv_flush_all(int cache)
-{
- BUG_ON(irqs_disabled() && !early_boot_irqs_disabled);
-
- if (cache && !static_cpu_has(X86_FEATURE_CLFLUSH)) {
- cpa_flush_all(cache);
- return true;
- }
-
- return false;
-}
-
-static void cpa_flush_range(unsigned long start, int numpages, int cache)
-{
- unsigned int i, level;
- unsigned long addr;
-
- WARN_ON(PAGE_ALIGN(start) != start);
-
- if (__inv_flush_all(cache))
- return;
-
- flush_tlb_kernel_range(start, start + PAGE_SIZE * numpages);
-
- if (!cache)
- return;
-
- /*
- * We only need to flush on one CPU,
- * clflush is a MESI-coherent instruction that
- * will cause all other CPUs to flush the same
- * cachelines:
- */
- for (i = 0, addr = start; i < numpages; i++, addr += PAGE_SIZE) {
- pte_t *pte = lookup_address(addr, &level);
-
- /*
- * Only flush present addresses:
- */
- if (pte && (pte_val(*pte) & _PAGE_PRESENT))
- clflush_cache_range((void *) addr, PAGE_SIZE);
- }
-}
-
-void __cpa_flush_array(void *data)
+void __cpa_flush_tlb(void *data)
{
struct cpa_data *cpa = data;
unsigned int i;
@@ -357,33 +313,31 @@ void __cpa_flush_array(void *data)
__flush_tlb_one_kernel(__cpa_addr(cpa, i));
}

-static void cpa_flush_array(struct cpa_data *cpa, int cache)
+static void cpa_flush(struct cpa_data *data, int cache)
{
+ struct cpa_data *cpa = data;
unsigned int i;

- if (cpa_check_flush_all(cache))
+ BUG_ON(irqs_disabled() && !early_boot_irqs_disabled);
+
+ if (cache && !static_cpu_has(X86_FEATURE_CLFLUSH)) {
+ cpa_flush_all(cache);
return;
+ }

if (cpa->numpages <= tlb_single_page_flush_ceiling)
- on_each_cpu(__cpa_flush_array, cpa, 1);
+ on_each_cpu(__cpa_flush_tlb, cpa, 1);
else
flush_tlb_all();

if (!cache)
return;

- /*
- * We only need to flush on one CPU,
- * clflush is a MESI-coherent instruction that
- * will cause all other CPUs to flush the same
- * cachelines:
- */
for (i = 0; i < cpa->numpages; i++) {
unsigned long addr = __cpa_addr(cpa, i);
unsigned int level;
- pte_t *pte;

- pte = lookup_address(addr, &level);
+ pte_t *pte = lookup_address(addr, &level);

/*
* Only flush present addresses:
@@ -1698,7 +1652,6 @@ static int change_page_attr_set_clr(unsi
{
struct cpa_data cpa;
int ret, cache, checkalias;
- unsigned long baddr = 0;

memset(&cpa, 0, sizeof(cpa));

@@ -1732,11 +1685,6 @@ static int change_page_attr_set_clr(unsi
*/
WARN_ON_ONCE(1);
}
- /*
- * Save address for cache flush. *addr is modified in the call
- * to __change_page_attr_set_clr() below.
- */
- baddr = make_addr_canonical_again(*addr);
}

/* Must avoid aliasing mappings in the highmem code */
@@ -1784,11 +1732,7 @@ static int change_page_attr_set_clr(unsi
goto out;
}

- if (cpa.flags & (CPA_PAGES_ARRAY | CPA_ARRAY))
- cpa_flush_array(&cpa, cache);
- else
- cpa_flush_range(baddr, numpages, cache);
-
+ cpa_flush(&cpa, cache);
out:
return ret;
}
@@ -2097,18 +2041,18 @@ static int __set_memory_enc_dec(unsigned
/*
* Before changing the encryption attribute, we need to flush caches.
*/
- cpa_flush_range(addr, numpages, 1);
+ cpa_flush(&cpa, 1);

ret = __change_page_attr_set_clr(&cpa, 1);

/*
- * After changing the encryption attribute, we need to flush TLBs
- * again in case any speculative TLB caching occurred (but no need
- * to flush caches again). We could just use cpa_flush_all(), but
- * in case TLB flushing gets optimized in the cpa_flush_range()
- * path use the same logic as above.
+ * After changing the encryption attribute, we need to flush TLBs again
+ * in case any speculative TLB caching occurred (but no need to flush
+ * caches again). We could just use cpa_flush_all(), but in case TLB
+ * flushing gets optimized in the cpa_flush() path use the same logic
+ * as above.
*/
- cpa_flush_range(addr, numpages, 0);
+ cpa_flush(&cpa, 0);

return ret;
}

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