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 <redacted>
---
arch/mips/mm/init.c | 39 ++++++++++++++++++++++++++-------------
1 file changed, 26 insertions(+), 13 deletions(-)
diff --git a/arch/mips/mm/init.c b/arch/mips/mm/init.c
index 19347dc6bbf8..1f5bdd18ae7c 100644
--- a/arch/mips/mm/init.c
+++ b/arch/mips/mm/init.c
@@ -171,22 +171,35 @@ 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);
+ /* Make sure this page is cleared on other CPU's too before using it */
}
- 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
On Sat, Aug 07, 2021 at 04:04:29PM +0800, Huang Pei wrote:
quoted hunk
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 <redacted>
---
arch/mips/mm/init.c | 39 ++++++++++++++++++++++++++-------------
1 file changed, 26 insertions(+), 13 deletions(-)
diff --git a/arch/mips/mm/init.c b/arch/mips/mm/init.c
index 19347dc6bbf8..1f5bdd18ae7c 100644
--- a/arch/mips/mm/init.c
+++ b/arch/mips/mm/init.c
@@ -171,22 +171,35 @@ 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)) {
please fix indentation and place page_mapping() to same column as
cpu_has_dc_aliases()
+ 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))
same here
+ flush_data_cache_page((unsigned long)vto);
+ kunmap_atomic(vto);
+ /* Make sure this page is cleared on other CPU's too before using it */
this comment should stay in front of the smp_wmb()
}
- 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();
Thomas.
--
Crap can work. Given enough thrust pigs will fly, but it's not necessarily a
good idea. [ RFC1925, 2.3 ]