[PATCH 1/4] MIPS: rework local_t operation on MIPS64

[PATCH 1/4] MIPS: rework local_t operation on MIPS64

[Huang Pei]

+. Use daddu/dsubu for long int on MIPS64.

+. remove "asm/war.h" since R10000_LLSC_WAR became a config option

+. clean up, no function changed

Suggested-by:  "Maciej W. Rozycki" <macro@orcam.me.uk>
Signed-off-by: Huang Pei <huangpei@loongson.cn>
---
 arch/mips/include/asm/asm.h   | 18 ++++++++++
 arch/mips/include/asm/local.h | 62 +++++++++--------------------------
 2 files changed, 33 insertions(+), 47 deletions(-)

diff --git a/arch/mips/include/asm/asm.h b/arch/mips/include/asm/asm.h
index 2f8ce94ebaaf..f3302b13d3e0 100644
--- a/arch/mips/include/asm/asm.h
+++ b/arch/mips/include/asm/asm.h
@@ -19,6 +19,7 @@
 
 #include <asm/sgidefs.h>
 #include <asm/asm-eva.h>
+#include <asm/isa-rev.h>
 
 #ifndef __VDSO__
 /*
@@ -211,6 +212,8 @@ symbol		=	value
 #define LONG_SUB	sub
 #define LONG_SUBU	subu
 #define LONG_L		lw
+#define LONG_LL		ll
+#define LONG_SC		sc
 #define LONG_S		sw
 #define LONG_SP		swp
 #define LONG_SLL	sll
@@ -236,6 +239,8 @@ symbol		=	value
 #define LONG_SUB	dsub
 #define LONG_SUBU	dsubu
 #define LONG_L		ld
+#define LONG_LL		lld
+#define LONG_SC		scd
 #define LONG_S		sd
 #define LONG_SP		sdp
 #define LONG_SLL	dsll
@@ -320,6 +325,19 @@ symbol		=	value
 
 #define SSNOP		sll zero, zero, 1
 
+/*
+ * Using a branch-likely instruction to check the result of an sc instruction
+ * works around a bug present in R10000 CPUs prior to revision 3.0 that could
+ * cause ll-sc sequences to execute non-atomically.
+ */
+#ifdef CONFIG_WAR_R10000_LLSC
+# define SC_BEQZ	beqzl
+#elif MIPS_ISA_REV >= 6
+# define SC_BEQZ	beqzc
+#else
+# define SC_BEQZ	beqz
+#endif
+
 #ifdef CONFIG_SGI_IP28
 /* Inhibit speculative stores to volatile (e.g.DMA) or invalid addresses. */
 #include <asm/cacheops.h>
diff --git a/arch/mips/include/asm/local.h b/arch/mips/include/asm/local.h
index ecda7295ddcd..c1e109357110 100644
--- a/arch/mips/include/asm/local.h
+++ b/arch/mips/include/asm/local.h
@@ -7,7 +7,7 @@
 #include <linux/atomic.h>
 #include <asm/cmpxchg.h>
 #include <asm/compiler.h>
-#include <asm/war.h>
+#include <asm/asm.h>
 
 typedef struct
 {
@@ -31,34 +31,18 @@ static __inline__ long local_add_return(long i, local_t * l)
 {
 	unsigned long result;
 
-	if (kernel_uses_llsc && IS_ENABLED(CONFIG_WAR_R10000_LLSC)) {
-		unsigned long temp;
-
-		__asm__ __volatile__(
-		"	.set	push					\n"
-		"	.set	arch=r4000				\n"
-			__SYNC(full, loongson3_war) "			\n"
-		"1:"	__LL	"%1, %2		# local_add_return	\n"
-		"	addu	%0, %1, %3				\n"
-			__SC	"%0, %2					\n"
-		"	beqzl	%0, 1b					\n"
-		"	addu	%0, %1, %3				\n"
-		"	.set	pop					\n"
-		: "=&r" (result), "=&r" (temp), "=m" (l->a.counter)
-		: "Ir" (i), "m" (l->a.counter)
-		: "memory");
-	} else if (kernel_uses_llsc) {
+	if (kernel_uses_llsc) {
 		unsigned long temp;
 
 		__asm__ __volatile__(
 		"	.set	push					\n"
 		"	.set	"MIPS_ISA_ARCH_LEVEL"			\n"
-			__SYNC(full, loongson3_war) "			\n"
-		"1:"	__LL	"%1, %2		# local_add_return	\n"
-		"	addu	%0, %1, %3				\n"
-			__SC	"%0, %2					\n"
-		"	beqz	%0, 1b					\n"
-		"	addu	%0, %1, %3				\n"
+			__SYNC(full, loongson3_war) "                   \n"
+		"1:"	__stringify(LONG_LL)	"	%1, %2		\n"
+		"	"__stringify(LONG_ADDU)	"	%0, %1, %3	\n"
+		"	"__stringify(LONG_SC)	"	%0, %2		\n"
+		"	"__stringify(SC_BEQZ)	"	%0, 1b		\n"
+		"	"__stringify(LONG_ADDU)	"	%0, %1, %3	\n"
 		"	.set	pop					\n"
 		: "=&r" (result), "=&r" (temp), "=m" (l->a.counter)
 		: "Ir" (i), "m" (l->a.counter)
@@ -80,34 +64,18 @@ static __inline__ long local_sub_return(long i, local_t * l)
 {
 	unsigned long result;
 
-	if (kernel_uses_llsc && IS_ENABLED(CONFIG_WAR_R10000_LLSC)) {
-		unsigned long temp;
-
-		__asm__ __volatile__(
-		"	.set	push					\n"
-		"	.set	arch=r4000				\n"
-			__SYNC(full, loongson3_war) "			\n"
-		"1:"	__LL	"%1, %2		# local_sub_return	\n"
-		"	subu	%0, %1, %3				\n"
-			__SC	"%0, %2					\n"
-		"	beqzl	%0, 1b					\n"
-		"	subu	%0, %1, %3				\n"
-		"	.set	pop					\n"
-		: "=&r" (result), "=&r" (temp), "=m" (l->a.counter)
-		: "Ir" (i), "m" (l->a.counter)
-		: "memory");
-	} else if (kernel_uses_llsc) {
+	if (kernel_uses_llsc) {
 		unsigned long temp;
 
 		__asm__ __volatile__(
 		"	.set	push					\n"
 		"	.set	"MIPS_ISA_ARCH_LEVEL"			\n"
-			__SYNC(full, loongson3_war) "			\n"
-		"1:"	__LL	"%1, %2		# local_sub_return	\n"
-		"	subu	%0, %1, %3				\n"
-			__SC	"%0, %2					\n"
-		"	beqz	%0, 1b					\n"
-		"	subu	%0, %1, %3				\n"
+			__SYNC(full, loongson3_war) "                   \n"
+		"1:"	__stringify(LONG_LL)	"	%1, %2		\n"
+		"	"__stringify(LONG_SUBU)	"	%0, %1, %3	\n"
+		"	"__stringify(LONG_SC)	"	%0, %2		\n"
+		"	"__stringify(SC_BEQZ)	"	%0, 1b		\n"
+		"	"__stringify(LONG_SUBU)	"	%0, %1, %3	\n"
 		"	.set	pop					\n"
 		: "=&r" (result), "=&r" (temp), "=m" (l->a.counter)
 		: "Ir" (i), "m" (l->a.counter)
-- 
2.20.1

[PATCH 2/4] MIPS: fix tx39_flush_cache_page

[Huang Pei]

Indexed cache operation need KSEG0 address for safety and assume
that no dcache alias nor high memory

Signed-off-by: Huang Pei <huangpei@loongson.cn>
---
 arch/mips/mm/c-tx39.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/arch/mips/mm/c-tx39.c b/arch/mips/mm/c-tx39.c
index 03dfbb40ec73..49e4a16186ce 100644
--- a/arch/mips/mm/c-tx39.c
+++ b/arch/mips/mm/c-tx39.c
@@ -170,6 +170,7 @@ static void tx39_flush_cache_page(struct vm_area_struct *vma, unsigned long page
 	struct mm_struct *mm = vma->vm_mm;
 	pmd_t *pmdp;
 	pte_t *ptep;
+	unsigned long vaddr = phys_to_virt(pfn_to_phys(pfn));
 
 	/*
 	 * If ownes no valid ASID yet, cannot possibly have gotten
@@ -207,11 +208,14 @@ static void tx39_flush_cache_page(struct vm_area_struct *vma, unsigned long page
 	/*
 	 * Do indexed flush, too much work to get the (possible) TLB refills
 	 * to work correctly.
+	 *
+	 * Assuming that tx39 family do not support high memory, nor has
+	 * dcache alias, vaddr can index dcache directly and correctly
 	 */
 	if (cpu_has_dc_aliases || exec)
-		tx39_blast_dcache_page_indexed(page);
+		tx39_blast_dcache_page_indexed(vaddr);
 	if (exec)
-		tx39_blast_icache_page_indexed(page);
+		tx39_blast_icache_page_indexed(vaddr);
 }
 
 static void local_tx39_flush_data_cache_page(void * addr)
-- 
2.20.1

[PATCH 3/4] MIPS: use 3-level pgtable for 64KB page size on MIPS_VA_BITS_48

[Huang Pei]

It hangup when booting Loongson 3A1000 with BOTH
CONFIG_PAGE_SIZE_64KB and CONFIG_MIPS_VA_BITS_48, that it turn
out to use 2-level pgtable instead of 3-level. 64KB page size
with 2-level pgtable only cover 42 bits VA, use 3-level pgtable
to cover all 48 bits VA(55 bits)

Fixes: 1e321fa917fb ("MIPS64: Support of at least 48 bits of SEGBITS)
Signed-off-by: Huang Pei <huangpei@loongson.cn>
---
 arch/mips/Kconfig | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index de60ad190057..0215dc1529e9 100644
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -3097,7 +3097,7 @@ config STACKTRACE_SUPPORT
 config PGTABLE_LEVELS
 	int
 	default 4 if PAGE_SIZE_4KB && MIPS_VA_BITS_48
-	default 3 if 64BIT && !PAGE_SIZE_64KB
+	default 3 if 64BIT && (!PAGE_SIZE_64KB || MIPS_VA_BITS_48)
 	default 2
 
 config MIPS_AUTO_PFN_OFFSET
-- 
2.20.1

[PATCH 4/4] MIPS: fix FTLB configuration

[Huang Pei]

Commit "da1bd29742b1" makes 'set_ftlb_enable' called under
c->cputype unset, which leaves FTLB disabled on BOTH 3A2000
and 3A3000

Fixes: da1bd29742b1 ("MIPS: Loongson64: Probe CPU features via CPUCFG")
Signed-off-by: Huang Pei <huangpei@loongson.cn>
---
 arch/mips/kernel/cpu-probe.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/mips/kernel/cpu-probe.c b/arch/mips/kernel/cpu-probe.c
index ac0e2cfc6d57..24a529c6c4be 100644
--- a/arch/mips/kernel/cpu-probe.c
+++ b/arch/mips/kernel/cpu-probe.c
@@ -1734,8 +1734,6 @@ static inline void decode_cpucfg(struct cpuinfo_mips *c)
 
 static inline void cpu_probe_loongson(struct cpuinfo_mips *c, unsigned int cpu)
 {
-	decode_configs(c);
-
 	/* All Loongson processors covered here define ExcCode 16 as GSExc. */
 	c->options |= MIPS_CPU_GSEXCEX;
 
@@ -1796,6 +1794,8 @@ static inline void cpu_probe_loongson(struct cpuinfo_mips *c, unsigned int cpu)
 		panic("Unknown Loongson Processor ID!");
 		break;
 	}
+
+	decode_configs(c);
 }
 #else
 static inline void cpu_probe_loongson(struct cpuinfo_mips *c, unsigned int cpu) { }
-- 
2.20.1