2018-12-27 20:54:28 +00:00
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From: Jeff Hansen <jhansen@cardaccess-inc.com>
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Subject: [PATCH] kmap_coherent
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On ASUS WL-500gP there are some "Data bus error"s when executing simple
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commands liks "ps" or "cat /proc/1/cmdline".
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This fixes OpenWrt ticket #1485: https://dev.openwrt.org/ticket/1485
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---
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--- a/arch/mips/include/asm/cpu-features.h
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+++ b/arch/mips/include/asm/cpu-features.h
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@@ -226,6 +226,9 @@
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#ifndef cpu_has_local_ebase
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#define cpu_has_local_ebase 1
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#endif
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+#ifndef cpu_use_kmap_coherent
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+#define cpu_use_kmap_coherent 1
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+#endif
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/*
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* I-Cache snoops remote store. This only matters on SMP. Some multiprocessors
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--- a/arch/mips/include/asm/mach-bcm47xx/cpu-feature-overrides.h
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+++ b/arch/mips/include/asm/mach-bcm47xx/cpu-feature-overrides.h
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@@ -80,4 +80,6 @@
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#define cpu_scache_line_size() 0
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#define cpu_has_vz 0
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+#define cpu_use_kmap_coherent 0
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+
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#endif /* __ASM_MACH_BCM47XX_CPU_FEATURE_OVERRIDES_H */
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--- a/arch/mips/mm/c-r4k.c
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+++ b/arch/mips/mm/c-r4k.c
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2019-01-16 23:01:18 +00:00
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@@ -694,7 +694,7 @@ static inline void local_r4k_flush_cache
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2018-12-27 20:54:28 +00:00
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map_coherent = (cpu_has_dc_aliases &&
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page_mapcount(page) &&
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!Page_dcache_dirty(page));
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- if (map_coherent)
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+ if (map_coherent && cpu_use_kmap_coherent)
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vaddr = kmap_coherent(page, addr);
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else
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vaddr = kmap_atomic(page);
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2019-01-16 23:01:18 +00:00
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@@ -719,7 +719,7 @@ static inline void local_r4k_flush_cache
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2018-12-27 20:54:28 +00:00
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}
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if (vaddr) {
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- if (map_coherent)
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+ if (map_coherent && cpu_use_kmap_coherent)
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kunmap_coherent();
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else
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kunmap_atomic(vaddr);
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--- a/arch/mips/mm/init.c
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+++ b/arch/mips/mm/init.c
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@@ -168,7 +168,7 @@ void copy_user_highpage(struct page *to,
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void *vfrom, *vto;
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vto = kmap_atomic(to);
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- if (cpu_has_dc_aliases &&
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+ if (cpu_has_dc_aliases && cpu_use_kmap_coherent &&
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page_mapcount(from) && !Page_dcache_dirty(from)) {
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vfrom = kmap_coherent(from, vaddr);
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copy_page(vto, vfrom);
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@@ -190,7 +190,7 @@ void copy_to_user_page(struct vm_area_st
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struct page *page, unsigned long vaddr, void *dst, const void *src,
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unsigned long len)
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{
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- if (cpu_has_dc_aliases &&
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+ if (cpu_has_dc_aliases && cpu_use_kmap_coherent &&
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page_mapcount(page) && !Page_dcache_dirty(page)) {
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void *vto = kmap_coherent(page, vaddr) + (vaddr & ~PAGE_MASK);
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memcpy(vto, src, len);
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@@ -208,7 +208,7 @@ void copy_from_user_page(struct vm_area_
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struct page *page, unsigned long vaddr, void *dst, const void *src,
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unsigned long len)
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{
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- if (cpu_has_dc_aliases &&
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+ if (cpu_has_dc_aliases && cpu_use_kmap_coherent &&
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page_mapcount(page) && !Page_dcache_dirty(page)) {
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void *vfrom = kmap_coherent(page, vaddr) + (vaddr & ~PAGE_MASK);
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memcpy(dst, vfrom, len);
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