diff options
author | Andreas Schwab <schwab@linux-m68k.org> | 2015-09-23 23:12:09 +0200 |
---|---|---|
committer | Geert Uytterhoeven <geert@linux-m68k.org> | 2015-09-28 09:59:45 +0200 |
commit | 8474ba74193d302e8340dddd1e16c85cc4b98caf (patch) | |
tree | f95d6e941e2f940e32cc711c2784062fb4cb5466 /arch/m68k/configs/mac_defconfig | |
parent | 7f843dab134b7ce8804b67cca2271267d3a0213d (diff) |
m68k: Define asmlinkage_protect
Make sure the compiler does not modify arguments of syscall functions.
This can happen if the compiler generates a tailcall to another
function. For example, without asmlinkage_protect sys_openat is compiled
into this function:
sys_openat:
clr.l %d0
move.w 18(%sp),%d0
move.l %d0,16(%sp)
jbra do_sys_open
Note how the fourth argument is modified in place, modifying the register
%d4 that gets restored from this stack slot when the function returns to
user-space. The caller may expect the register to be unmodified across
system calls.
Signed-off-by: Andreas Schwab <schwab@linux-m68k.org>
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: stable@vger.kernel.org
Diffstat (limited to 'arch/m68k/configs/mac_defconfig')
0 files changed, 0 insertions, 0 deletions