Commit d6efd3f1 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

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
parents 80be5998 ebdc20d7

arch/alpha/include/asm/setup.h

0 → 100644
+43 −0
Original line number Diff line number Diff line 
/* 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

+3 −39
Original line number Diff line number Diff line 
/* 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

+1 −1
Original line number Diff line number Diff line
@@ -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

+2 −0
Original line number Diff line number Diff line
@@ -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)						\