[PATCH 2/2] riscv/include/uapi: Define a custom __SIGINFO struct for RV32

[Alistair Francis]

The glibc implementation of siginfo_t results in an allignment of 8 bytes
for the union _sifields on RV32. The kernel has an allignment of 4 bytes
for the _sifields union. This results in information being lost when
glibc parses the siginfo_t struct.

To fix the issue add a pad variable to the struct to avoid allignment
mismatches.

Signed-off-by: Alistair Francis <alistair.francis@xxxxxxx>
---
 arch/riscv/include/uapi/asm/siginfo.h | 32 +++++++++++++++++++++++++++
 1 file changed, 32 insertions(+)
 create mode 100644 arch/riscv/include/uapi/asm/siginfo.h

diff --git a/arch/riscv/include/uapi/asm/siginfo.h b/arch/riscv/include/uapi/asm/siginfo.h
new file mode 100644
index 000000000000..0854ad97bf44
--- /dev/null
+++ b/arch/riscv/include/uapi/asm/siginfo.h
@@ -0,0 +1,32 @@
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+#ifndef _ASM_RISCV_SIGINFO_H
+#define _ASM_RISCV_SIGINFO_H
+
+/* Add a pad element for RISC-V 32-bit. We need this as the
+ * _sifields union is 8 byte allgined in usperace.
+ */
+#if __riscv_xlen == 32
+#ifndef __ARCH_HAS_SWAPPED_SIGINFO
+#define __SIGINFO 			\
+struct {				\
+	int si_signo;			\
+	int si_errno;			\
+	int si_code;			\
+	int pad;			\
+	union __sifields _sifields;	\
+}
+#else
+#define __SIGINFO 			\
+struct {				\
+	int si_signo;			\
+	int si_code;			\
+	int si_errno;			\
+	int pad;			\
+	union __sifields _sifields;	\
+}
+#endif /* __ARCH_HAS_SWAPPED_SIGINFO */
+#endif
+
+#include <asm-generic/siginfo.h>
+
+#endif /* _ASM_RISCV_SIGINFO_H */
-- 
2.22.0