Commit a074335a37 ("x86, um: Mark system call tables readonly") was
supposed to mark the sys_call_table in UML as RO by adding the const,
but it doesn't have the desired effect as it's nevertheless being placed
into the data section since __cacheline_aligned enforces sys_call_table
being placed into .data..cacheline_aligned instead. We need to use
the ____cacheline_aligned version instead to fix this issue.
Before:
$ nm -v arch/x86/um/sys_call_table_64.o | grep -1 "sys_call_table"
U sys_writev
0000000000000000 D sys_call_table
0000000000000000 D syscall_table_size
After:
$ nm -v arch/x86/um/sys_call_table_64.o | grep -1 "sys_call_table"
U sys_writev
0000000000000000 R sys_call_table
0000000000000000 D syscall_table_size
Fixes: a074335a37 ("x86, um: Mark system call tables readonly")
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
Conditional on CONFIG_GENERIC_SIGALTSTACK; architectures that do not
select it are completely unaffected
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Split the 64-bit system calls into "64" (64-bit only) and "common"
(64-bit or x32) and add the x32 system call numbers.
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Mark the system call tables readonly, as they already are on native,
and the 32-bit UM version was in the previous assembly version. The
32-bit version lost it due to copy and paste from the 64-bit version,
which was missing the const.
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Richard Weinberger <richard@nod.at>
Link: http://lkml.kernel.org/r/tip-45db1c6176c8171d9ae6fa6d82e07d115a5950ca@git.kernel.org
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Now when the native kernel uses a single style of generated system
call table, follow suite for UML and implement the same style, all in
C. This requires __NR_syscall_max and NR_syscalls to be generated; on
native this is done in asm-headers.h but that file is common to all
UML architectures; therefore put it in user-headers.h instead which
already have accommodations for architecture-specific values.
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
