1 files changed, 42 insertions, 8 deletions

diff --git a/arch/parisc/include/asm/fixmap.h b/arch/parisc/include/asm/fixmap.h
index 6fec4d4a1a18..9cafa449c4a7 100644
--- a/arch/parisc/include/asm/fixmap.h
+++ b/arch/parisc/include/asm/fixmap.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #ifndef _ASM_FIXMAP_H
 #define _ASM_FIXMAP_H
 
@@ -8,23 +9,56 @@
  *
  * All of the values in this file must be <4GB (because of assembly
  * loading restrictions).  If you place this region anywhere above
- * __PAGE_OFFSET, you must adjust the memory map accordingly */
+ * __PAGE_OFFSET, you must adjust the memory map accordingly
+ */
 
-/* The alias region is used in kernel space to do copy/clear to or
- * from areas congruently mapped with user space.  It is 8MB large
- * and must be 16MB aligned */
-#define TMPALIAS_MAP_START	((__PAGE_OFFSET) - 16*1024*1024)
+/*
+ * The tmpalias region is used in kernel space to copy/clear/flush data
+ * from pages congruently mapped with user space. It is comprised of
+ * a pair regions. The size of these regions is determined by the largest
+ * cache aliasing boundary for machines that support equivalent aliasing.
+ *
+ * The c3750 with PA8700 processor returns an alias value of 11. This
+ * indicates that it has an alias boundary of 4 MB. It also supports
+ * non-equivalent aliasing without a performance penalty.
+ *
+ * Machines with PA8800/PA8900 processors return an alias value of 0.
+ * This indicates the alias boundary is unknown and may be larger than
+ * 16 MB. Non-equivalent aliasing is not supported.
+ *
+ * Here we assume the maximum alias boundary is 4 MB.
+ */
+#define TMPALIAS_SIZE_BITS	22	/* 4 MB */
+#define TMPALIAS_MAP_START	((__PAGE_OFFSET) - (2 << TMPALIAS_SIZE_BITS))
+
+#define FIXMAP_SIZE		(FIX_BITMAP_COUNT << PAGE_SHIFT)
+#define FIXMAP_START		(TMPALIAS_MAP_START - FIXMAP_SIZE)
 /* This is the kernel area for all maps (vmalloc, dma etc.)  most
  * usually, it extends up to TMPALIAS_MAP_START.  Virtual addresses
  * 0..GATEWAY_PAGE_SIZE are reserved for the gateway page */
 #define KERNEL_MAP_START	(GATEWAY_PAGE_SIZE)
-#define KERNEL_MAP_END		(TMPALIAS_MAP_START)
+#define KERNEL_MAP_END		(FIXMAP_START)
+
+#ifndef __ASSEMBLER__
+
+
+enum fixed_addresses {
+	/* Support writing RO kernel text via kprobes, jump labels, etc. */
+	FIX_TEXT_POKE0,
+	FIX_TEXT_KEXEC,
+	FIX_BITMAP_COUNT
+};
 
-#ifndef __ASSEMBLY__
 extern void *parisc_vmalloc_start;
 #define PCXL_DMA_MAP_SIZE	(8*1024*1024)
 #define VMALLOC_START		((unsigned long)parisc_vmalloc_start)
 #define VMALLOC_END		(KERNEL_MAP_END)
-#endif /*__ASSEMBLY__*/
+
+#define __fix_to_virt(_x) (FIXMAP_START + ((_x) << PAGE_SHIFT))
+
+void set_fixmap(enum fixed_addresses idx, phys_addr_t phys);
+void clear_fixmap(enum fixed_addresses idx);
+
+#endif /*__ASSEMBLER__*/
 
 #endif /*_ASM_FIXMAP_H*/