For now, we can remove STACK_FRAME_NON_STANDARD(do_syscall) because
there is no objtool warning "do_syscall+0x11c: return with modified
stack frame", then there is handle_syscall() which is the previous
frame of do_syscall() in the call trace when executing the command
"echo l > /proc/sysrq-trigger".
Fixes: a0f7085f6a63 ("LoongArch: Add RANDOMIZE_KSTACK_OFFSET support")
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Add support of kernel stack offset randomization while handling syscall,
the offset is defaultly limited by KSTACK_OFFSET_MAX().
In order to avoid triggering stack canaries (due to __builtin_alloca())
and slowing down the entry path, use __no_stack_protector attribute to
disable stack protector for do_syscall() at function level.
With this patch, the REPORT_STACK test show that:
`loongarch64 bits of stack entropy: 7`
Reviewed-by: Kees Cook <kees@kernel.org>
Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
The uapi/asm/unistd_64.h and asm/syscall_table_64.h headers can now be
generated from scripts/syscall.tbl, which makes this consistent with
the other architectures that have their own syscall.tbl.
Unlike the other architectures using the asm-generic header, loongarch
uses none of the deprecated system calls at the moment.
Both the user visible side of asm/unistd.h and the internal syscall
table in the kernel should have the same effective contents after this.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Most architectures that implement the old-style mmap() with byte offset
use 'unsigned long' as the type for that offset, but microblaze and
riscv have the off_t type that is shared with userspace, matching the
prototype in include/asm-generic/syscalls.h.
Make this consistent by using an unsigned argument everywhere. This
changes the behavior slightly, as the argument is shifted to a page
number, and an user input with the top bit set would result in a
negative page offset rather than a large one as we use elsewhere.
For riscv, the 32-bit sys_mmap2() definition actually used a custom
type that is different from the global declaration, but this was
missed due to an incorrect type check.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Add system call support and related uaccess.h for LoongArch.
Q: Why keep _ARCH_WANT_SYS_CLONE definition while there is clone3:
A: The latest glibc release has some basic support for clone3 but it is
not complete. E.g., pthread_create() and spawni() have converted to
use clone3 but fork() will still use clone. Moreover, some seccomp
related applications can still not work perfectly with clone3. E.g.,
Chromium sandbox cannot work at all and there is no solution for it,
which is more terrible than the fork() story [1].
[1] https://chromium-review.googlesource.com/c/chromium/src/+/2936184
Reviewed-by: WANG Xuerui <git@xen0n.name>
Reviewed-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
