summaryrefslogtreecommitdiffstats
path: root/arch/powerpc/mm/cacheflush.c
diff options
context:
space:
mode:
Diffstat (limited to '')
-rw-r--r--arch/powerpc/mm/cacheflush.c234
1 files changed, 234 insertions, 0 deletions
diff --git a/arch/powerpc/mm/cacheflush.c b/arch/powerpc/mm/cacheflush.c
new file mode 100644
index 000000000..0e9b4879c
--- /dev/null
+++ b/arch/powerpc/mm/cacheflush.c
@@ -0,0 +1,234 @@
+// 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
+ * Return true if the cache was flushed, false otherwise
+ */
+static inline bool flush_coherent_icache(void)
+{
+ /*
+ * 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 actual stores to memory that might
+ * have modified instructions with the icbi.
+ */
+ if (cpu_has_feature(CPU_FTR_COHERENT_ICACHE)) {
+ mb(); /* sync */
+ icbi((void *)PAGE_OFFSET);
+ 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())
+ 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);
+
+#ifdef CONFIG_HIGHMEM
+/**
+ * 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)
+#else
+static void flush_dcache_icache_phys(unsigned long physaddr)
+{
+}
+#endif
+
+/**
+ * __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.
+ *
+ * @p: the address of the page to flush
+ */
+static void __flush_dcache_icache(void *p)
+{
+ unsigned long addr = (unsigned long)p & PAGE_MASK;
+
+ 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);
+}
+
+static void flush_dcache_icache_hugepage(struct page *page)
+{
+ int i;
+ int nr = compound_nr(page);
+
+ if (!PageHighMem(page)) {
+ for (i = 0; i < nr; i++)
+ __flush_dcache_icache(lowmem_page_address(page + i));
+ } else {
+ for (i = 0; i < nr; i++) {
+ void *start = kmap_local_page(page + i);
+
+ __flush_dcache_icache(start);
+ kunmap_local(start);
+ }
+ }
+}
+
+void flush_dcache_icache_page(struct page *page)
+{
+ if (flush_coherent_icache())
+ return;
+
+ if (PageCompound(page))
+ return flush_dcache_icache_hugepage(page);
+
+ if (!PageHighMem(page)) {
+ __flush_dcache_icache(lowmem_page_address(page));
+ } else if (IS_ENABLED(CONFIG_BOOKE) || sizeof(phys_addr_t) > sizeof(void *)) {
+ void *start = kmap_local_page(page);
+
+ __flush_dcache_icache(start);
+ kunmap_local(start);
+ } else {
+ flush_dcache_icache_phys(page_to_phys(page));
+ }
+}
+EXPORT_SYMBOL(flush_dcache_icache_page);
+
+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)
+{
+ void *maddr;
+
+ maddr = kmap_local_page(page) + (addr & ~PAGE_MASK);
+ flush_icache_range((unsigned long)maddr, (unsigned long)maddr + len);
+ kunmap_local(maddr);
+}