* [PATCH] MIPS: simplify copy_user_high_page for MIPS64 w/o cache alias
2021-09-08 8:22 [Patch V2]; MIPS: simplify copy_user_high_page for MIPS64 w/o cache alias Huang Pei
@ 2021-09-08 8:22 ` Huang Pei
0 siblings, 0 replies; 2+ messages in thread
From: Huang Pei @ 2021-09-08 8:22 UTC (permalink / raw)
To: Thomas Bogendoerfer, ambrosehua
Cc: Bibo Mao, linux-mips, linux-rt-users, Jiaxun Yang, Li Xuefeng,
Yang Tiezhu, Gao Juxin, Huacai Chen, Jinyang He
Borrow from ARM64
MIPS64 CPU has enough direct mapped memory space to access all
physical memory. In case of no cache alias, bypass both kmap_atomic
and kmap_coherent for better real-time performance.
Signed-off-by: Huang Pei <huangpei@loongson.cn>
---
arch/mips/mm/init.c | 37 +++++++++++++++++++++++++------------
1 file changed, 25 insertions(+), 12 deletions(-)
diff --git a/arch/mips/mm/init.c b/arch/mips/mm/init.c
index 19347dc6bbf8..d9923fd9ed3b 100644
--- a/arch/mips/mm/init.c
+++ b/arch/mips/mm/init.c
@@ -171,21 +171,34 @@ 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();
}
--
2.25.1
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