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

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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
This commit is contained in:
Linus Torvalds 2021-09-15 12:11:48 -07:00
commit d6efd3f187
4 changed files with 49 additions and 40 deletions
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43
arch/alpha/include/asm/setup.h Normal file
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@ -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

42
arch/alpha/include/uapi/asm/setup.h
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@ -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 */

2
drivers/net/ethernet/i825xx/82596.c
View File

@ -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;

2
include/linux/compiler.h
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@ -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) \