powerpc: Convert flush_icache_range & friends to C

[ Upstream commit 23eb7f5 ]

Similar to commit 22e9c88
("powerpc/64: reuse PPC32 static inline flush_dcache_range()")
this patch converts the following ASM symbols to C:
    flush_icache_range()
    __flush_dcache_icache()
    __flush_dcache_icache_phys()

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 these functions to C, it becomes easier to maintain.

flush_dcache_icache_phys() retains a critical assembler section as we must
ensure there are no memory accesses while the data MMU is disabled
(authored by Christophe Leroy). Since this has no external callers, it has
also been made static, allowing the compiler to inline it within
flush_dcache_icache_page().

Signed-off-by: Alastair D'Silva <[email protected]>
Signed-off-by: Christophe Leroy <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
[mpe: Minor fixups, don't export __flush_dcache_icache()]
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Sasha Levin <[email protected]>

Author: deece

arch/powerpc/include/asm/cache.h

@@ -96,22 +96,7 @@ static inline u32 l1_icache_bytes(void)
 }
 
 #endif
-#endif /* ! __ASSEMBLY__ */
-
-#if defined(__ASSEMBLY__)
-/*
- * For a snooping icache, we still need a dummy icbi to purge all the
- * prefetched instructions from the ifetch buffers. We also need a sync
- * before the icbi to order the the actual stores to memory that might
- * have modified instructions with the icbi.
- */
-#define PURGE_PREFETCHED_INS	\
-	sync;			\
-	icbi	0,r3;		\
-	sync;			\
-	isync
 
-#else
 #define __read_mostly __attribute__((__section__(".data..read_mostly")))
 
 #ifdef CONFIG_PPC_BOOK3S_32
@@ -145,6 +130,17 @@ static inline void dcbst(void *addr)
 {
 	__asm__ __volatile__ ("dcbst 0, %0" : : "r"(addr) : "memory");
 }
+
+static inline void icbi(void *addr)
+{
+	asm volatile ("icbi 0, %0" : : "r"(addr) : "memory");
+}
+
+static inline void iccci(void *addr)
+{
+	asm volatile ("iccci 0, %0" : : "r"(addr) : "memory");
+}
+
 #endif /* !__ASSEMBLY__ */
 #endif /* __KERNEL__ */
 #endif /* _ASM_POWERPC_CACHE_H */

arch/powerpc/include/asm/cacheflush.h

@@ -42,24 +42,20 @@ 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);
+void flush_icache_range(unsigned long start, unsigned long stop);
 extern void flush_icache_user_range(struct vm_area_struct *vma,
 				    struct page *page, unsigned long addr,
 				    int len);
-extern void __flush_dcache_icache(void *page_va);
 extern void flush_dcache_icache_page(struct page *page);
-#if defined(CONFIG_PPC32) && !defined(CONFIG_BOOKE)
-extern void __flush_dcache_icache_phys(unsigned long physaddr);
-#else
-static inline void __flush_dcache_icache_phys(unsigned long physaddr)
-{
-	BUG();
-}
-#endif
-
-/*
- * Write any modified data cache blocks out to memory and invalidate them.
- * Does not invalidate the corresponding instruction cache blocks.
+void __flush_dcache_icache(void *page);
+
+/**
+ * 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)
 {

arch/powerpc/kernel/misc_32.S

@@ -316,126 +316,6 @@ _GLOBAL(flush_instruction_cache)
 EXPORT_SYMBOL(flush_instruction_cache)
 #endif /* CONFIG_PPC_8xx */
 
-/*
- * Write any modified data cache blocks out to memory
- * and invalidate the corresponding instruction cache blocks.
- * This is a no-op on the 601.
- *
- * flush_icache_range(unsigned long start, unsigned long stop)
- */
-_GLOBAL(flush_icache_range)
-#if defined(CONFIG_PPC_BOOK3S_601) || defined(CONFIG_E200)
-	PURGE_PREFETCHED_INS
-	blr				/* for 601 and e200, do nothing */
-#else
-	rlwinm	r3,r3,0,0,31 - L1_CACHE_SHIFT
-	subf	r4,r3,r4
-	addi	r4,r4,L1_CACHE_BYTES - 1
-	srwi.	r4,r4,L1_CACHE_SHIFT
-	beqlr
-	mtctr	r4
-	mr	r6,r3
-1:	dcbst	0,r3
-	addi	r3,r3,L1_CACHE_BYTES
-	bdnz	1b
-	sync				/* wait for dcbst's to get to ram */
-#ifndef CONFIG_44x
-	mtctr	r4
-2:	icbi	0,r6
-	addi	r6,r6,L1_CACHE_BYTES
-	bdnz	2b
-#else
-	/* Flash invalidate on 44x because we are passed kmapped addresses and
-	   this doesn't work for userspace pages due to the virtually tagged
-	   icache.  Sigh. */
-	iccci	0, r0
-#endif
-	sync				/* additional sync needed on g4 */
-	isync
-	blr
-#endif
-_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*
- * snoop from the data cache.
- * This is a no-op on the 601 and e200 which have a unified cache.
- *
- *	void __flush_dcache_icache(void *page)
- */
-_GLOBAL(__flush_dcache_icache)
-#if defined(CONFIG_PPC_BOOK3S_601) || defined(CONFIG_E200)
-	PURGE_PREFETCHED_INS
-	blr
-#else
-	rlwinm	r3,r3,0,0,31-PAGE_SHIFT		/* Get page base address */
-	li	r4,PAGE_SIZE/L1_CACHE_BYTES	/* Number of lines in a page */
-	mtctr	r4
-	mr	r6,r3
-0:	dcbst	0,r3				/* Write line to ram */
-	addi	r3,r3,L1_CACHE_BYTES
-	bdnz	0b
-	sync
-#ifdef CONFIG_44x
-	/* We don't flush the icache on 44x. Those have a virtual icache
-	 * and we don't have access to the virtual address here (it's
-	 * not the page vaddr but where it's mapped in user space). The
-	 * flushing of the icache on these is handled elsewhere, when
-	 * a change in the address space occurs, before returning to
-	 * user space
-	 */
-BEGIN_MMU_FTR_SECTION
-	blr
-END_MMU_FTR_SECTION_IFSET(MMU_FTR_TYPE_44x)
-#endif /* CONFIG_44x */
-	mtctr	r4
-1:	icbi	0,r6
-	addi	r6,r6,L1_CACHE_BYTES
-	bdnz	1b
-	sync
-	isync
-	blr
-#endif
-
-#ifndef CONFIG_BOOKE
-/*
- * Flush a particular page from the data cache to RAM, identified
- * by its physical address.  We turn off the MMU so we can just use
- * the physical address (this may be a highmem page without a kernel
- * mapping).
- *
- *	void __flush_dcache_icache_phys(unsigned long physaddr)
- */
-_GLOBAL(__flush_dcache_icache_phys)
-#if defined(CONFIG_PPC_BOOK3S_601) || defined(CONFIG_E200)
-	PURGE_PREFETCHED_INS
-	blr					/* for 601 and e200, do nothing */
-#else
-	mfmsr	r10
-	rlwinm	r0,r10,0,28,26			/* clear DR */
-	mtmsr	r0
-	isync
-	rlwinm	r3,r3,0,0,31-PAGE_SHIFT		/* Get page base address */
-	li	r4,PAGE_SIZE/L1_CACHE_BYTES	/* Number of lines in a page */
-	mtctr	r4
-	mr	r6,r3
-0:	dcbst	0,r3				/* Write line to ram */
-	addi	r3,r3,L1_CACHE_BYTES
-	bdnz	0b
-	sync
-	mtctr	r4
-1:	icbi	0,r6
-	addi	r6,r6,L1_CACHE_BYTES
-	bdnz	1b
-	sync
-	mtmsr	r10				/* restore DR */
-	isync
-	blr
-#endif
-#endif /* CONFIG_BOOKE */
-
 /*
  * Copy a whole page.  We use the dcbz instruction on the destination
  * to reduce memory traffic (it eliminates the unnecessary reads of

arch/powerpc/kernel/misc_64.S

@@ -49,108 +49,6 @@ _GLOBAL(call_do_irq)
 	mtlr	r0
 	blr
 
-	.section	".toc","aw"
-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*
- * snoop from the data cache.
- *
- *	void __flush_dcache_icache(void *page)
- */
-_GLOBAL(__flush_dcache_icache)
-/*
- * Flush the data cache to memory 
- * 
- * Different systems have different cache line sizes
- */
-
-BEGIN_FTR_SECTION
-	PURGE_PREFETCHED_INS
-	blr
-END_FTR_SECTION_IFSET(CPU_FTR_COHERENT_ICACHE)
-
-/* Flush the dcache */
- 	ld	r7,PPC64_CACHES@toc(r2)
-	clrrdi	r3,r3,PAGE_SHIFT           	    /* Page align */
-	lwz	r4,DCACHEL1BLOCKSPERPAGE(r7)	/* Get # dcache blocks per page */
-	lwz	r5,DCACHEL1BLOCKSIZE(r7)	/* Get dcache block size */
-	mr	r6,r3
-	mtctr	r4
-0:	dcbst	0,r6
-	add	r6,r6,r5
-	bdnz	0b
-	sync
-
-/* Now invalidate the icache */	
-
-	lwz	r4,ICACHEL1BLOCKSPERPAGE(r7)	/* Get # icache blocks per page */
-	lwz	r5,ICACHEL1BLOCKSIZE(r7)	/* Get icache block size */
-	mtctr	r4
-1:	icbi	0,r3
-	add	r3,r3,r5
-	bdnz	1b
-	isync
-	blr
-
 _GLOBAL(__bswapdi2)
 EXPORT_SYMBOL(__bswapdi2)
 	srdi	r8,r3,32