diff options
| author | Andreas Schwab <schwab@linux-m68k.org> | 2015-09-23 23:12:09 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2015-10-22 14:37:53 -0700 |
| commit | 46409b7e4b56dd58779fb148d870353588a925ae (patch) | |
| tree | e6f1c7700074c5c52efa7e481424f28ece0ba687 /drivers/net | |
| parent | 339cb27fc56dd226e6ec59b15010527b12b0411a (diff) | |
m68k: Define asmlinkage_protect
commit 8474ba74193d302e8340dddd1e16c85cc4b98caf upstream.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/net')
0 files changed, 0 insertions, 0 deletions