riscv: align stack before calling _dl_init [BZ #28703]

Align the stack pointer to 128 bits during the call to _dl_init() as
specified by the RISC-V ABI [1]. This fixes the elf/tst-align2 test.

Fixes bug 28703.

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

(cherry picked from commit 225da459cebef1037dcd78b56471edc0721e1c41)

diff --git a/NEWS b/NEWS
index 873491df1f7156fcd8c7a17fce39a42db009dd94..d9b344027b6b2af7faab006ea2993b851caf1226 100644 (file)
--- a/NEWS
+++ b/NEWS
@@ -25,6 +25,7 @@ The following bugs are resolved with this release:
   [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
+  [28703] RISC-V: _dl_init might be called with unaligned stack
   [28704] elf/tst-cpu-features-cpuinfo fails for KVM guests on some AMD systems
 
 \f

diff --git a/sysdeps/riscv/dl-machine.h b/sysdeps/riscv/dl-machine.h
index aedf69fcdd8aff50b83ea66fe0fdbafa8b38d07b..951268923da26a373a91e924cb1ce76702ca03e6 100644 (file)
--- a/sysdeps/riscv/dl-machine.h
+++ b/sysdeps/riscv/dl-machine.h
@@ -127,8 +127,14 @@ elf_machine_load_address (void)
        sll a3, a1, " STRINGXP (PTRLOG) "\n\
        add a3, a3, a2\n\
        add a3, a3, " STRINGXP (SZREG) "\n\
+       # Stash the stack pointer in s1.\n\
+       mv s1, sp\n\
+       # Align stack to 128 bits for the _dl_init call.\n\
+       andi sp, sp,-16\n\
        # Call the function to run the initializers.\n\
        jal _dl_init\n\
+       # Restore the stack pointer for _start.\n\
+       mv sp, s1\n\
        # Pass our finalizer function to _start.\n\
        lla a0, _dl_fini\n\
        # Jump to the user entry point.\n\