From f6b5f1a56987de837f8e25cd560847106b8632a8 Mon Sep 17 00:00:00 2001 From: Guenter Roeck Date: Tue, 14 Sep 2021 20:52:24 -0700 Subject: [PATCH 1/4] compiler.h: Introduce absolute_pointer macro absolute_pointer() disassociates a pointer from its originating symbol type and context. Use it to prevent compiler warnings/errors such as 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. Suggested-by: Linus Torvalds Signed-off-by: Guenter Roeck Reviewed-by: Geert Uytterhoeven Signed-off-by: Linus Torvalds --- include/linux/compiler.h | 2 ++ 1 file changed, 2 insertions(+) diff --git a/include/linux/compiler.h b/include/linux/compiler.h index b67261a1e3e9..3d5af56337bd 100644 --- a/include/linux/compiler.h +++ b/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) \ From dff2d13114f0beec448da9b3716204eb34b0cf41 Mon Sep 17 00:00:00 2001 From: Guenter Roeck Date: Tue, 14 Sep 2021 20:52:25 -0700 Subject: [PATCH 2/4] net: i825xx: Use absolute_pointer for memcpy from fixed memory location gcc 11.x reports the following compiler warning/error. 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] Use absolute_pointer() to work around the problem. Cc: Geert Uytterhoeven Signed-off-by: Guenter Roeck Reviewed-by: Geert Uytterhoeven Signed-off-by: Linus Torvalds --- drivers/net/ethernet/i825xx/82596.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/net/ethernet/i825xx/82596.c b/drivers/net/ethernet/i825xx/82596.c index b8a40146b895..b482f6f633bd 100644 --- a/drivers/net/ethernet/i825xx/82596.c +++ b/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; From 3cb8b1537f8a89a681d2548ded5526280846f6db Mon Sep 17 00:00:00 2001 From: Guenter Roeck Date: Tue, 14 Sep 2021 20:52:26 -0700 Subject: [PATCH 3/4] alpha: Move setup.h out of uapi Most of the contents of setup.h have no value for userspace applications. The file was probably moved to uapi accidentally. Keep the file in uapi to define the alpha-specific COMMAND_LINE_SIZE. Move all other defines to arch/alpha/include/asm/setup.h. Suggested-by: Linus Torvalds Signed-off-by: Guenter Roeck Signed-off-by: Linus Torvalds --- arch/alpha/include/asm/setup.h | 43 +++++++++++++++++++++++++++++ arch/alpha/include/uapi/asm/setup.h | 42 ++-------------------------- 2 files changed, 46 insertions(+), 39 deletions(-) create mode 100644 arch/alpha/include/asm/setup.h diff --git a/arch/alpha/include/asm/setup.h b/arch/alpha/include/asm/setup.h new file mode 100644 index 000000000000..58fe3f45a235 --- /dev/null +++ b/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 + +/* + * 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 diff --git a/arch/alpha/include/uapi/asm/setup.h b/arch/alpha/include/uapi/asm/setup.h index 13b7ee465b0e..f881ea5947cb 100644 --- a/arch/alpha/include/uapi/asm/setup.h +++ b/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 */ From ebdc20d7bc74e8b6a242ff1f30e9017ffca9092c Mon Sep 17 00:00:00 2001 From: Guenter Roeck Date: Tue, 14 Sep 2021 20:52:27 -0700 Subject: [PATCH 4/4] alpha: Use absolute_pointer to define COMMAND_LINE alpha:allmodconfig fails to build with the following error when using gcc 11.x. arch/alpha/kernel/setup.c: In function 'setup_arch': arch/alpha/kernel/setup.c:493:13: error: 'strcmp' reading 1 or more bytes from a region of size 0 Avoid the problem by declaring COMMAND_LINE as absolute_pointer(). Signed-off-by: Guenter Roeck Signed-off-by: Linus Torvalds --- arch/alpha/include/asm/setup.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/alpha/include/asm/setup.h b/arch/alpha/include/asm/setup.h index 58fe3f45a235..262aab99e391 100644 --- a/arch/alpha/include/asm/setup.h +++ b/arch/alpha/include/asm/setup.h @@ -36,7 +36,7 @@ * place. */ #define PARAM ZERO_PGE -#define COMMAND_LINE ((char *)(PARAM + 0x0000)) +#define COMMAND_LINE ((char *)(absolute_pointer(PARAM + 0x0000))) #define INITRD_START (*(unsigned long *) (PARAM+0x100)) #define INITRD_SIZE (*(unsigned long *) (PARAM+0x108))