Merge branch 'absolute-pointer' (patches from Guenter)

Merge absolute_pointer macro series from Guenter Roeck:
 "Kernel test builds currently fail for several architectures with error
  messages such as the following.

  drivers/net/ethernet/i825xx/82596.c: In function 'i82596_probe':
  arch/m68k/include/asm/string.h:72:25: error:
        '__builtin_memcpy' reading 6 bytes from a region of size 0
                [-Werror=stringop-overread]

  Such warnings may be reported by gcc 11.x for string and memory
  operations on fixed addresses if gcc's builtin functions are used for
  those operations.

  This series introduces absolute_pointer() to fix the problem.
  absolute_pointer() disassociates a pointer from its originating symbol
  type and context, and thus prevents gcc from making assumptions about
  pointers passed to memory operations"

* emailed patches from Guenter Roeck <linux@roeck-us.net>:
  alpha: Use absolute_pointer to define COMMAND_LINE
  alpha: Move setup.h out of uapi
  net: i825xx: Use absolute_pointer for memcpy from fixed memory location
  compiler.h: Introduce absolute_pointer macro

arch/alpha/include/asm/setup.h

@@ -0,0 +1,43 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+#ifndef __ALPHA_SETUP_H
+#define __ALPHA_SETUP_H
+
+#include <uapi/asm/setup.h>
+
+/*
+ * We leave one page for the initial stack page, and one page for
+ * the initial process structure. Also, the console eats 3 MB for
+ * the initial bootloader (one of which we can reclaim later).
+ */
+#define BOOT_PCB	0x20000000
+#define BOOT_ADDR	0x20000000
+/* Remove when official MILO sources have ELF support: */
+#define BOOT_SIZE	(16*1024)
+
+#ifdef CONFIG_ALPHA_LEGACY_START_ADDRESS
+#define KERNEL_START_PHYS	0x300000 /* Old bootloaders hardcoded this.  */
+#else
+#define KERNEL_START_PHYS	0x1000000 /* required: Wildfire/Titan/Marvel */
+#endif
+
+#define KERNEL_START	(PAGE_OFFSET+KERNEL_START_PHYS)
+#define SWAPPER_PGD	KERNEL_START
+#define INIT_STACK	(PAGE_OFFSET+KERNEL_START_PHYS+0x02000)
+#define EMPTY_PGT	(PAGE_OFFSET+KERNEL_START_PHYS+0x04000)
+#define EMPTY_PGE	(PAGE_OFFSET+KERNEL_START_PHYS+0x08000)
+#define ZERO_PGE	(PAGE_OFFSET+KERNEL_START_PHYS+0x0A000)
+
+#define START_ADDR	(PAGE_OFFSET+KERNEL_START_PHYS+0x10000)
+
+/*
+ * This is setup by the secondary bootstrap loader.  Because
+ * the zero page is zeroed out as soon as the vm system is
+ * initialized, we need to copy things out into a more permanent
+ * place.
+ */
+#define PARAM			ZERO_PGE
+#define COMMAND_LINE		((char *)(absolute_pointer(PARAM + 0x0000)))
+#define INITRD_START		(*(unsigned long *) (PARAM+0x100))
+#define INITRD_SIZE		(*(unsigned long *) (PARAM+0x108))
+
+#endif

arch/alpha/include/uapi/asm/setup.h

@@ -1,43 +1,7 @@
 /* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
-#ifndef __ALPHA_SETUP_H
-#define __ALPHA_SETUP_H
+#ifndef _UAPI__ALPHA_SETUP_H
+#define _UAPI__ALPHA_SETUP_H
 
 #define COMMAND_LINE_SIZE	256
 
-/*
- * We leave one page for the initial stack page, and one page for
- * the initial process structure. Also, the console eats 3 MB for
- * the initial bootloader (one of which we can reclaim later).
- */
-#define BOOT_PCB	0x20000000
-#define BOOT_ADDR	0x20000000
-/* Remove when official MILO sources have ELF support: */
-#define BOOT_SIZE	(16*1024)
-
-#ifdef CONFIG_ALPHA_LEGACY_START_ADDRESS
-#define KERNEL_START_PHYS	0x300000 /* Old bootloaders hardcoded this.  */
-#else
-#define KERNEL_START_PHYS	0x1000000 /* required: Wildfire/Titan/Marvel */
-#endif
-
-#define KERNEL_START	(PAGE_OFFSET+KERNEL_START_PHYS)
-#define SWAPPER_PGD	KERNEL_START
-#define INIT_STACK	(PAGE_OFFSET+KERNEL_START_PHYS+0x02000)
-#define EMPTY_PGT	(PAGE_OFFSET+KERNEL_START_PHYS+0x04000)
-#define EMPTY_PGE	(PAGE_OFFSET+KERNEL_START_PHYS+0x08000)
-#define ZERO_PGE	(PAGE_OFFSET+KERNEL_START_PHYS+0x0A000)
-
-#define START_ADDR	(PAGE_OFFSET+KERNEL_START_PHYS+0x10000)
-
-/*
- * This is setup by the secondary bootstrap loader.  Because
- * the zero page is zeroed out as soon as the vm system is
- * initialized, we need to copy things out into a more permanent
- * place.
- */
-#define PARAM			ZERO_PGE
-#define COMMAND_LINE		((char*)(PARAM + 0x0000))
-#define INITRD_START		(*(unsigned long *) (PARAM+0x100))
-#define INITRD_SIZE		(*(unsigned long *) (PARAM+0x108))
-
-#endif
+#endif /* _UAPI__ALPHA_SETUP_H */

drivers/net/ethernet/i825xx/82596.c

@@ -1144,7 +1144,7 @@ static struct net_device * __init i82596_probe(void)
 			err = -ENODEV;
 			goto out;
 		}
-		memcpy(eth_addr, (void *) 0xfffc1f2c, ETH_ALEN);	/* YUCK! Get addr from NOVRAM */
+		memcpy(eth_addr, absolute_pointer(0xfffc1f2c), ETH_ALEN); /* YUCK! Get addr from NOVRAM */
 		dev->base_addr = MVME_I596_BASE;
 		dev->irq = (unsigned) MVME16x_IRQ_I596;
 		goto found;

include/linux/compiler.h

@@ -188,6 +188,8 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val,
     (typeof(ptr)) (__ptr + (off)); })
 #endif
 
+#define absolute_pointer(val)	RELOC_HIDE((void *)(val), 0)
+
 #ifndef OPTIMIZER_HIDE_VAR
 /* Make the optimizer believe the variable can be manipulated arbitrarily. */
 #define OPTIMIZER_HIDE_VAR(var)						\