* [PATCH V2] MIPS: simplify copy_user_high_page for MIPS64 w/o cache
@ 2021-08-15 4:28 Huang Pei
2021-08-15 4:28 ` [PATCH] MIPS: simplify copy_user_high_page for MIPS64 w/o cache alias Huang Pei
0 siblings, 1 reply; 2+ messages in thread
From: Huang Pei @ 2021-08-15 4:28 UTC (permalink / raw)
To: Joseph Myers; +Cc: Huacai Chen, Chenghua Xu, libc-alpha
V2:
adjust indentation
^ permalink raw reply [flat|nested] 2+ messages in thread
* [PATCH] MIPS: simplify copy_user_high_page for MIPS64 w/o cache alias
2021-08-15 4:28 [PATCH V2] MIPS: simplify copy_user_high_page for MIPS64 w/o cache Huang Pei
@ 2021-08-15 4:28 ` Huang Pei
0 siblings, 0 replies; 2+ messages in thread
From: Huang Pei @ 2021-08-15 4:28 UTC (permalink / raw)
To: Joseph Myers; +Cc: Huacai Chen, Chenghua Xu, libc-alpha
Borrow from ARM64
MIPS64 CPU has enough direct mapped memory space to access all
physical memory. In case of no cache alias, bypass both k*map_atomic
and k*map_coherent for better real-time performance.
Signed-off-by: Huang Pei <huangpei@loongson.cn>
---
arch/mips/mm/init.c | 40 ++++++++++++++++++++++++++++------------
1 file changed, 28 insertions(+), 12 deletions(-)
diff --git a/arch/mips/mm/init.c b/arch/mips/mm/init.c
index 19347dc6bbf8..22183dc78a40 100644
--- a/arch/mips/mm/init.c
+++ b/arch/mips/mm/init.c
@@ -171,21 +171,37 @@ void copy_user_highpage(struct page *to, struct page *from,
{
void *vfrom, *vto;
- vto = kmap_atomic(to);
- if (cpu_has_dc_aliases &&
- page_mapcount(from) && !Page_dcache_dirty(from)) {
- vfrom = kmap_coherent(from, vaddr);
+ if (IS_ENABLED(CONFIG_64BIT) && !cpu_has_dc_aliases) {
+ vfrom = page_address(from);
+ vto = page_address(to);
copy_page(vto, vfrom);
- kunmap_coherent();
+ /*
+ * Even without cache alias, still need to maintain
+ * coherence between icache and dcache
+ */
+ if (!cpu_has_ic_fills_f_dc)
+ flush_data_cache_page((unsigned long)vto);
+
} else {
- vfrom = kmap_atomic(from);
- copy_page(vto, vfrom);
- kunmap_atomic(vfrom);
+ vto = kmap_atomic(to);
+
+ if (cpu_has_dc_aliases &&
+ page_mapcount(from) && !Page_dcache_dirty(from)) {
+ vfrom = kmap_coherent(from, vaddr);
+ copy_page(vto, vfrom);
+ kunmap_coherent();
+ } else {
+ vfrom = kmap_atomic(from);
+ copy_page(vto, vfrom);
+ kunmap_atomic(vfrom);
+ }
+
+ if ((!cpu_has_ic_fills_f_dc) ||
+ pages_do_alias((unsigned long)vto, vaddr & PAGE_MASK))
+ flush_data_cache_page((unsigned long)vto);
+
+ kunmap_atomic(vto);
}
- if ((!cpu_has_ic_fills_f_dc) ||
- pages_do_alias((unsigned long)vto, vaddr & PAGE_MASK))
- flush_data_cache_page((unsigned long)vto);
- kunmap_atomic(vto);
/* Make sure this page is cleared on other CPU's too before using it */
smp_wmb();
}
--
2.26.2
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