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From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Guenter Roeck <linux@roeck-us.net>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Geert Uytterhoeven <geert@linux-m68k.org>,
	Sasha Levin <sashal@kernel.org>,
	luc.vanoostenryck@gmail.com, linux-sparse@vger.kernel.org
Subject: [PATCH AUTOSEL 4.9 03/11] compiler.h: Introduce absolute_pointer macro
Date: Wed, 22 Sep 2021 23:40:19 -0400	[thread overview]
Message-ID: <20210923034028.1421876-3-sashal@kernel.org> (raw)
In-Reply-To: <20210923034028.1421876-1-sashal@kernel.org>

From: Guenter Roeck <linux@roeck-us.net>

[ Upstream commit f6b5f1a56987de837f8e25cd560847106b8632a8 ]

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 <torvalds@linux-foundation.org>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 include/linux/compiler.h | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/include/linux/compiler.h b/include/linux/compiler.h
index 824b1b97f989..10937279b152 100644
--- a/include/linux/compiler.h
+++ b/include/linux/compiler.h
@@ -233,6 +233,8 @@ void ftrace_likely_update(struct ftrace_branch_data *f, int val, int expect);
     (typeof(ptr)) (__ptr + (off)); })
 #endif
 
+#define absolute_pointer(val)	RELOC_HIDE((void *)(val), 0)
+
 #ifndef OPTIMIZER_HIDE_VAR
 #define OPTIMIZER_HIDE_VAR(var) barrier()
 #endif
-- 
2.30.2


  parent reply	other threads:[~2021-09-23  3:43 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-23  3:40 [PATCH AUTOSEL 4.9 01/11] net: stmmac: allow CSR clock of 300MHz Sasha Levin
2021-09-23  3:40 ` [PATCH AUTOSEL 4.9 02/11] m68k: Double cast io functions to unsigned long Sasha Levin
2021-09-23  3:40 ` Sasha Levin [this message]
2021-09-23  3:40 ` [PATCH AUTOSEL 4.9 04/11] net: i825xx: Use absolute_pointer for memcpy from fixed memory location Sasha Levin
2021-09-23  3:40 ` [PATCH AUTOSEL 4.9 05/11] sparc: avoid stringop-overread errors Sasha Levin
2021-09-23  3:40 ` [PATCH AUTOSEL 4.9 06/11] qnx4: " Sasha Levin
2021-09-23  3:40 ` [PATCH AUTOSEL 4.9 07/11] parisc: Use absolute_pointer() to define PAGE0 Sasha Levin
2021-09-23  3:40 ` [PATCH AUTOSEL 4.9 08/11] arm64: Mark __stack_chk_guard as __ro_after_init Sasha Levin
2021-09-23  3:40 ` [PATCH AUTOSEL 4.9 09/11] alpha: Declare virt_to_phys and virt_to_bus parameter as pointer to volatile Sasha Levin
2021-09-23  3:40 ` [PATCH AUTOSEL 4.9 10/11] net: 6pack: Fix tx timeout and slot time Sasha Levin
2021-09-23  3:40 ` [PATCH AUTOSEL 4.9 11/11] spi: Fix tegra20 build with CONFIG_PM=n Sasha Levin

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