[PATCH 2/2] powerpc: Convert flush_icache_range to C

[Alastair D'Silva]

From: Alastair D'Silva <alastair@xxxxxxxxxxx>

Similar to commit 22e9c88d486a
("powerpc/64: reuse PPC32 static inline flush_dcache_range()")
this patch converts flush_icache_range to C.

This was done as we discovered a long-standing bug where the
length of the range was truncated due to using a 32 bit shift
instead of a 64 bit one.

By converting this function to C, it becomes easier to maintain.

Signed-off-by: Alastair D'Silva <alastair@xxxxxxxxxxx>
---
 arch/powerpc/include/asm/cache.h      | 35 +++++++++++++--
 arch/powerpc/include/asm/cacheflush.h | 63 +++++++++++++++++++++++----
 arch/powerpc/kernel/misc_64.S         | 55 -----------------------
 3 files changed, 85 insertions(+), 68 deletions(-)

diff --git a/arch/powerpc/include/asm/cache.h b/arch/powerpc/include/asm/cache.h
index b3388d95f451..d3d7077b75e2 100644
--- a/arch/powerpc/include/asm/cache.h
+++ b/arch/powerpc/include/asm/cache.h
@@ -55,25 +55,46 @@ struct ppc64_caches {
 
 extern struct ppc64_caches ppc64_caches;
 
-static inline u32 l1_cache_shift(void)
+static inline u32 l1_dcache_shift(void)
 {
 	return ppc64_caches.l1d.log_block_size;
 }
 
-static inline u32 l1_cache_bytes(void)
+static inline u32 l1_dcache_bytes(void)
 {
 	return ppc64_caches.l1d.block_size;
 }
+
+static inline u32 l1_icache_shift(void)
+{
+	return ppc64_caches.l1i.log_block_size;
+}
+
+static inline u32 l1_icache_bytes(void)
+{
+	return ppc64_caches.l1i.block_size;
+}
 #else
-static inline u32 l1_cache_shift(void)
+static inline u32 l1_dcache_shift(void)
 {
 	return L1_CACHE_SHIFT;
 }
 
-static inline u32 l1_cache_bytes(void)
+static inline u32 l1_dcache_bytes(void)
 {
 	return L1_CACHE_BYTES;
 }
+
+static inline u32 l1_icache_shift(void)
+{
+	return L1_CACHE_SHIFT;
+}
+
+static inline u32 l1_icache_bytes(void)
+{
+	return L1_CACHE_BYTES;
+}
+
 #endif
 #endif /* ! __ASSEMBLY__ */
 
@@ -124,6 +145,12 @@ static inline void dcbst(void *addr)
 {
 	__asm__ __volatile__ ("dcbst %y0" : : "Z"(*(u8 *)addr) : "memory");
 }
+
+static inline void icbi(void *addr)
+{
+	__asm__ __volatile__ ("icbi %y0" : : "Z"(*(u8 *)addr) : "memory");
+}
+
 #endif /* !__ASSEMBLY__ */
 #endif /* __KERNEL__ */
 #endif /* _ASM_POWERPC_CACHE_H */
diff --git a/arch/powerpc/include/asm/cacheflush.h b/arch/powerpc/include/asm/cacheflush.h
index eef388f2659f..f68e75a6dc4b 100644
--- a/arch/powerpc/include/asm/cacheflush.h
+++ b/arch/powerpc/include/asm/cacheflush.h
@@ -42,7 +42,6 @@ extern void flush_dcache_page(struct page *page);
 #define flush_dcache_mmap_lock(mapping)		do { } while (0)
 #define flush_dcache_mmap_unlock(mapping)	do { } while (0)
 
-extern void flush_icache_range(unsigned long, unsigned long);
 extern void flush_icache_user_range(struct vm_area_struct *vma,
 				    struct page *page, unsigned long addr,
 				    int len);
@@ -57,14 +56,17 @@ static inline void __flush_dcache_icache_phys(unsigned long physaddr)
 }
 #endif
 
-/*
- * Write any modified data cache blocks out to memory and invalidate them.
+/**
+ * flush_dcache_range: Write any modified data cache blocks out to memory and invalidate them.
  * Does not invalidate the corresponding instruction cache blocks.
+ *
+ * @start: the start address
+ * @stop: the stop address (exclusive)
  */
 static inline void flush_dcache_range(unsigned long start, unsigned long stop)
 {
-	unsigned long shift = l1_cache_shift();
-	unsigned long bytes = l1_cache_bytes();
+	unsigned long shift = l1_dcache_shift();
+	unsigned long bytes = l1_dcache_bytes();
 	void *addr = (void *)(start & ~(bytes - 1));
 	unsigned long size = stop - (unsigned long)addr + (bytes - 1);
 	unsigned long i;
@@ -82,6 +84,49 @@ static inline void flush_dcache_range(unsigned long start, unsigned long stop)
 		isync();
 }
 
+/**
+ * flush_icache_range: Write any modified data cache blocks out to memory
+ * and invalidate the corresponding blocks in the instruction cache
+ *
+ * Generic code will call this after writing memory, before executing from it.
+ *
+ * @start: the start address
+ * @stop: the stop address (exclusive)
+ */
+static inline void flush_icache_range(unsigned long start, unsigned long stop)
+{
+	unsigned long shift = l1_dcache_shift();
+	unsigned long bytes = l1_dcache_bytes();
+	void *addr = (void *)(start & ~(bytes - 1));
+	unsigned long size = stop - (unsigned long)addr + (bytes - 1);
+	unsigned long i;
+
+	if (cpu_has_feature(CPU_FTR_COHERENT_ICACHE)) {
+		mb(); /* sync */
+		icbi((void *)start);
+		mb(); /* sync */
+		isync();
+		return;
+	}
+
+	/* Flush the data cache to memory */
+	for (i = 0; i < size >> shift; i++, addr += bytes)
+		dcbst(addr);
+
+	mb();	/* sync */
+
+	shift = l1_icache_shift();
+	bytes = l1_icache_bytes();
+	addr = (void *)(start & ~(bytes - 1));
+	size = stop - (unsigned long)addr + (bytes - 1);
+
+	/* Now invalidate the instruction cache */
+	for (i = 0; i < size >> shift; i++, addr += bytes)
+		icbi(addr);
+
+	isync();
+}
+
 /*
  * Write any modified data cache blocks out to memory.
  * Does not invalidate the corresponding cache lines (especially for
@@ -89,8 +134,8 @@ static inline void flush_dcache_range(unsigned long start, unsigned long stop)
  */
 static inline void clean_dcache_range(unsigned long start, unsigned long stop)
 {
-	unsigned long shift = l1_cache_shift();
-	unsigned long bytes = l1_cache_bytes();
+	unsigned long shift = l1_dcache_shift();
+	unsigned long bytes = l1_dcache_bytes();
 	void *addr = (void *)(start & ~(bytes - 1));
 	unsigned long size = stop - (unsigned long)addr + (bytes - 1);
 	unsigned long i;
@@ -108,8 +153,8 @@ static inline void clean_dcache_range(unsigned long start, unsigned long stop)
 static inline void invalidate_dcache_range(unsigned long start,
 					   unsigned long stop)
 {
-	unsigned long shift = l1_cache_shift();
-	unsigned long bytes = l1_cache_bytes();
+	unsigned long shift = l1_dcache_shift();
+	unsigned long bytes = l1_dcache_bytes();
 	void *addr = (void *)(start & ~(bytes - 1));
 	unsigned long size = stop - (unsigned long)addr + (bytes - 1);
 	unsigned long i;
diff --git a/arch/powerpc/kernel/misc_64.S b/arch/powerpc/kernel/misc_64.S
index 9bc0aa9aeb65..999828e86bba 100644
--- a/arch/powerpc/kernel/misc_64.S
+++ b/arch/powerpc/kernel/misc_64.S
@@ -54,61 +54,6 @@ PPC64_CACHES:
 	.tc		ppc64_caches[TC],ppc64_caches
 	.section	".text"
 
-/*
- * Write any modified data cache blocks out to memory
- * and invalidate the corresponding instruction cache blocks.
- *
- * flush_icache_range(unsigned long start, unsigned long stop)
- *
- *   flush all bytes from start through stop-1 inclusive
- */
-
-_GLOBAL_TOC(flush_icache_range)
-BEGIN_FTR_SECTION
-	PURGE_PREFETCHED_INS
-	blr
-END_FTR_SECTION_IFSET(CPU_FTR_COHERENT_ICACHE)
-/*
- * Flush the data cache to memory 
- * 
- * Different systems have different cache line sizes
- * and in some cases i-cache and d-cache line sizes differ from
- * each other.
- */
- 	ld	r10,PPC64_CACHES@toc(r2)
-	lwz	r7,DCACHEL1BLOCKSIZE(r10)/* Get cache block size */
-	addi	r5,r7,-1
-	andc	r6,r3,r5		/* round low to line bdy */
-	subf	r8,r6,r4		/* compute length */
-	add	r8,r8,r5		/* ensure we get enough */
-	lwz	r9,DCACHEL1LOGBLOCKSIZE(r10)	/* Get log-2 of cache block size */
-	srd.	r8,r8,r9		/* compute line count */
-	beqlr				/* nothing to do? */
-	mtctr	r8
-1:	dcbst	0,r6
-	add	r6,r6,r7
-	bdnz	1b
-	sync
-
-/* Now invalidate the instruction cache */
-	
-	lwz	r7,ICACHEL1BLOCKSIZE(r10)	/* Get Icache block size */
-	addi	r5,r7,-1
-	andc	r6,r3,r5		/* round low to line bdy */
-	subf	r8,r6,r4		/* compute length */
-	add	r8,r8,r5
-	lwz	r9,ICACHEL1LOGBLOCKSIZE(r10)	/* Get log-2 of Icache block size */
-	srd.	r8,r8,r9		/* compute line count */
-	beqlr				/* nothing to do? */
-	mtctr	r8
-2:	icbi	0,r6
-	add	r6,r6,r7
-	bdnz	2b
-	isync
-	blr
-_ASM_NOKPROBE_SYMBOL(flush_icache_range)
-EXPORT_SYMBOL(flush_icache_range)
-
 /*
  * Flush a particular page from the data cache to RAM.
  * Note: this is necessary because the instruction cache does *not*
-- 
2.21.0