[PATCH v2 0/4] Introduce and use absolute_pointer macro

From: Guenter Roeck
Date: Tue Sep 14 2021 - 23:52:34 EST


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 patch 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.

v2: Drop parisc patch (the problem will be solved differently)
alpha: Move setup.h out of uapi
Define COMMAND_LINE for alpha as absolute_pointer instead of using
absolute_pointer on the define.

----------------------------------------------------------------
Guenter Roeck (4):
compiler.h: Introduce absolute_pointer macro
net: i825xx: Use absolute_pointer for memcpy from fixed memory location
alpha: Move setup.h out of uapi
alpha: Use absolute_pointer to define COMMAND_LINE

arch/alpha/include/asm/setup.h | 43 +++++++++++++++++++++++++++++++++++++
arch/alpha/include/uapi/asm/setup.h | 42 +++---------------------------------
drivers/net/ethernet/i825xx/82596.c | 2 +-
include/linux/compiler.h | 2 ++
4 files changed, 49 insertions(+), 40 deletions(-)
create mode 100644 arch/alpha/include/asm/setup.h