[COMMITTED 2.34] riscv: align stack in clone [BZ #28702]

[Aurelien Jarno]

The RISC-V ABI [1] mandates that "the stack pointer shall be aligned to
a 128-bit boundary upon procedure entry". This as not the case in clone.

This fixes the misc/tst-misalign-clone-internal and
misc/tst-misalign-clone tests.

Fixes bug 28702.

[1] https://github.com/riscv-non-isa/riscv-elf-psabi-doc

(cherry picked from commit d2e594d71509faf36cf851a69370db34a4f5fa65)
---
 NEWS                                  | 1 +
 sysdeps/unix/sysv/linux/riscv/clone.S | 3 +++
 2 files changed, 4 insertions(+)

diff --git a/NEWS b/NEWS
index 1214ec4727..873491df1f 100644
--- a/NEWS
+++ b/NEWS
@@ -24,6 +24,7 @@ The following bugs are resolved with this release:
   [28532] powerpc64[le]: CFI for assembly templated syscalls is incorrect
   [28678] nptl/tst-create1 hangs sporadically
   [28700] "dns [!UNAVAIL=return] files" NSS default for hosts is not useful
+  [28702] RISC-V: clone does not align stack
   [28704] elf/tst-cpu-features-cpuinfo fails for KVM guests on some AMD systems
 
 
diff --git a/sysdeps/unix/sysv/linux/riscv/clone.S b/sysdeps/unix/sysv/linux/riscv/clone.S
index 12f91a20d3..161e83c7e3 100644
--- a/sysdeps/unix/sysv/linux/riscv/clone.S
+++ b/sysdeps/unix/sysv/linux/riscv/clone.S
@@ -32,6 +32,9 @@
 	.text
 LEAF (__clone)
 
+	/* Align stack to a 128-bit boundary as per RISC-V ABI.  */
+	andi		a1,a1,ALMASK
+
 	/* Sanity check arguments.  */
 	beqz		a0,L (invalid)	/* No NULL function pointers.  */
 	beqz		a1,L (invalid)	/* No NULL stack pointers.  */
-- 
2.33.0