[PATCH v3 1/5] microblaze: wire up sigaltstack

[Ramin Moussavi]

sigaltstack is wired to sys_ni_syscall - microblaze is the only
architecture without it - although the microblaze signal delivery code
fully supports the alternate signal stack: get_sigframe() picks the
stack via sigsp(), setup_rt_frame() saves it with __save_altstack() and
sys_rt_sigreturn() calls restore_altstack().

Wire it up to sys_sigaltstack.

Tested on qemu petalogix-s3adsp1800 (microblazeel) with the uClibc-ng
test suite: the five sigaltstack-dependent NPTL tests (tst-cancel20/21,
tst-cancelx20/21, tst-signal6) pass; before this change sigaltstack()
returned ENOSYS.

Assisted-by: Claude:claude-opus-5
Signed-off-by: Ramin Moussavi <ramin.moussavi@xxxxxxxxx>
---
 arch/microblaze/kernel/syscalls/syscall.tbl | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/microblaze/kernel/syscalls/syscall.tbl b/arch/microblaze/kernel/syscalls/syscall.tbl
index 223d26303627..b4ce48e8a874 100644
--- a/arch/microblaze/kernel/syscalls/syscall.tbl
+++ b/arch/microblaze/kernel/syscalls/syscall.tbl
@@ -193,7 +193,7 @@
 183	common	getcwd				sys_getcwd
 184	common	capget				sys_capget
 185	common	capset				sys_capset
-186	common	sigaltstack			sys_ni_syscall
+186	common	sigaltstack			sys_sigaltstack
 187	common	sendfile			sys_sendfile
 188	common	getpmsg				sys_ni_syscall
 189	common	putpmsg				sys_ni_syscall
-- 
2.53.0