1 files changed, 255 insertions, 0 deletions
diff --git a/arch/powerpc/mm/cacheflush.c b/arch/powerpc/mm/cacheflush.c
new file mode 100644
index 000000000000..40613d2fda37
--- /dev/null
+++ b/arch/powerpc/mm/cacheflush.c
@@ -0,0 +1,255 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include <linux/highmem.h>
+#include <linux/kprobes.h>
+
+/**
+ * flush_coherent_icache() - if a CPU has a coherent icache, flush it
+ * @addr: The base address to use (can be any valid address, the whole cache will be flushed)
+ * Return true if the cache was flushed, false otherwise
+ */
+static inline bool flush_coherent_icache(unsigned long addr)
+{
+	/*
+	 * 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.
+	 */
+	if (cpu_has_feature(CPU_FTR_COHERENT_ICACHE)) {
+		mb(); /* sync */
+		allow_read_from_user((const void __user *)addr, L1_CACHE_BYTES);
+		icbi((void *)addr);
+		prevent_read_from_user((const void __user *)addr, L1_CACHE_BYTES);
+		mb(); /* sync */
+		isync();
+		return true;
+	}
+
+	return false;
+}
+
+/**
+ * invalidate_icache_range() - Flush the icache by issuing icbi across an address range
+ * @start: the start address
+ * @stop: the stop address (exclusive)
+ */
+static void invalidate_icache_range(unsigned long start, unsigned long stop)
+{
+	unsigned long shift = l1_icache_shift();
+	unsigned long bytes = l1_icache_bytes();
+	char *addr = (char *)(start & ~(bytes - 1));
+	unsigned long size = stop - (unsigned long)addr + (bytes - 1);
+	unsigned long i;
+
+	for (i = 0; i < size >> shift; i++, addr += bytes)
+		icbi(addr);
+
+	mb(); /* sync */
+	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)
+ */
+void flush_icache_range(unsigned long start, unsigned long stop)
+{
+	if (flush_coherent_icache(start))
+		return;
+
+	clean_dcache_range(start, stop);
+
+	if (IS_ENABLED(CONFIG_44x)) {
+		/*
+		 * Flash invalidate on 44x because we are passed kmapped
+		 * addresses and this doesn't work for userspace pages due to
+		 * the virtually tagged icache.
+		 */
+		iccci((void *)start);
+		mb(); /* sync */
+		isync();
+	} else
+		invalidate_icache_range(start, stop);
+}
+EXPORT_SYMBOL(flush_icache_range);
+
+#if !defined(CONFIG_PPC_8xx) && !defined(CONFIG_PPC64)
+/**
+ * flush_dcache_icache_phys() - Flush a page by it's physical address
+ * @physaddr: the physical address of the page
+ */
+static void flush_dcache_icache_phys(unsigned long physaddr)
+{
+	unsigned long bytes = l1_dcache_bytes();
+	unsigned long nb = PAGE_SIZE / bytes;
+	unsigned long addr = physaddr & PAGE_MASK;
+	unsigned long msr, msr0;
+	unsigned long loop1 = addr, loop2 = addr;
+
+	msr0 = mfmsr();
+	msr = msr0 & ~MSR_DR;
+	/*
+	 * This must remain as ASM to prevent potential memory accesses
+	 * while the data MMU is disabled
+	 */
+	asm volatile(
+		"   mtctr %2;\n"
+		"   mtmsr %3;\n"
+		"   isync;\n"
+		"0: dcbst   0, %0;\n"
+		"   addi    %0, %0, %4;\n"
+		"   bdnz    0b;\n"
+		"   sync;\n"
+		"   mtctr %2;\n"
+		"1: icbi    0, %1;\n"
+		"   addi    %1, %1, %4;\n"
+		"   bdnz    1b;\n"
+		"   sync;\n"
+		"   mtmsr %5;\n"
+		"   isync;\n"
+		: "+&r" (loop1), "+&r" (loop2)
+		: "r" (nb), "r" (msr), "i" (bytes), "r" (msr0)
+		: "ctr", "memory");
+}
+NOKPROBE_SYMBOL(flush_dcache_icache_phys)
+#endif // !defined(CONFIG_PPC_8xx) && !defined(CONFIG_PPC64)
+
+/*
+ * This is called when a page has been modified by the kernel.
+ * It just marks the page as not i-cache clean.  We do the i-cache
+ * flush later when the page is given to a user process, if necessary.
+ */
+void flush_dcache_page(struct page *page)
+{
+	if (cpu_has_feature(CPU_FTR_COHERENT_ICACHE))
+		return;
+	/* avoid an atomic op if possible */
+	if (test_bit(PG_dcache_clean, &page->flags))
+		clear_bit(PG_dcache_clean, &page->flags);
+}
+EXPORT_SYMBOL(flush_dcache_page);
+
+static void flush_dcache_icache_hugepage(struct page *page)
+{
+	int i;
+	void *start;
+
+	BUG_ON(!PageCompound(page));
+
+	for (i = 0; i < compound_nr(page); i++) {
+		if (!PageHighMem(page)) {
+			__flush_dcache_icache(page_address(page+i));
+		} else {
+			start = kmap_atomic(page+i);
+			__flush_dcache_icache(start);
+			kunmap_atomic(start);
+		}
+	}
+}
+
+void flush_dcache_icache_page(struct page *page)
+{
+
+	if (PageCompound(page))
+		return flush_dcache_icache_hugepage(page);
+
+#if defined(CONFIG_PPC_8xx) || defined(CONFIG_PPC64)
+	/* On 8xx there is no need to kmap since highmem is not supported */
+	__flush_dcache_icache(page_address(page));
+#else
+	if (IS_ENABLED(CONFIG_BOOKE) || sizeof(phys_addr_t) > sizeof(void *)) {
+		void *start = kmap_atomic(page);
+		__flush_dcache_icache(start);
+		kunmap_atomic(start);
+	} else {
+		unsigned long addr = page_to_pfn(page) << PAGE_SHIFT;
+
+		if (flush_coherent_icache(addr))
+			return;
+		flush_dcache_icache_phys(addr);
+	}
+#endif
+}
+EXPORT_SYMBOL(flush_dcache_icache_page);
+
+/**
+ * __flush_dcache_icache(): 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.
+ *
+ * @page: the address of the page to flush
+ */
+void __flush_dcache_icache(void *p)
+{
+	unsigned long addr = (unsigned long)p;
+
+	if (flush_coherent_icache(addr))
+		return;
+
+	clean_dcache_range(addr, addr + PAGE_SIZE);
+
+	/*
+	 * 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.
+	 */
+
+	if (mmu_has_feature(MMU_FTR_TYPE_44x))
+		return;
+
+	invalidate_icache_range(addr, addr + PAGE_SIZE);
+}
+
+void clear_user_page(void *page, unsigned long vaddr, struct page *pg)
+{
+	clear_page(page);
+
+	/*
+	 * We shouldn't have to do this, but some versions of glibc
+	 * require it (ld.so assumes zero filled pages are icache clean)
+	 * - Anton
+	 */
+	flush_dcache_page(pg);
+}
+EXPORT_SYMBOL(clear_user_page);
+
+void copy_user_page(void *vto, void *vfrom, unsigned long vaddr,
+		    struct page *pg)
+{
+	copy_page(vto, vfrom);
+
+	/*
+	 * We should be able to use the following optimisation, however
+	 * there are two problems.
+	 * Firstly a bug in some versions of binutils meant PLT sections
+	 * were not marked executable.
+	 * Secondly the first word in the GOT section is blrl, used
+	 * to establish the GOT address. Until recently the GOT was
+	 * not marked executable.
+	 * - Anton
+	 */
+#if 0
+	if (!vma->vm_file && ((vma->vm_flags & VM_EXEC) == 0))
+		return;
+#endif
+
+	flush_dcache_page(pg);
+}
+
+void flush_icache_user_page(struct vm_area_struct *vma, struct page *page,
+			     unsigned long addr, int len)
+{
+	unsigned long maddr;
+
+	maddr = (unsigned long) kmap(page) + (addr & ~PAGE_MASK);
+	flush_icache_range(maddr, maddr + len);
+	kunmap(page);
+}