[RFC PATCH V2 31/38] riscv: s64ilp32: Add u32ilp32 signal support

[guoren@kernel.org]

From: Guo Ren <guoren@linux.alibaba.com>

The u32ilp32 uses the compat_pt_regs instead of the native pt_regs, so
we borrow the compat code to support the u32ilp32 signal procedure in
the s64ilp32 kernel.

Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Signed-off-by: Guo Ren <guoren@kernel.org>
---
 arch/riscv/include/asm/signal32.h |  2 +-
 arch/riscv/kernel/Makefile        |  1 +
 arch/riscv/kernel/signal.c        |  5 ++++-
 kernel/signal.c                   | 24 ++++++++++++++----------
 4 files changed, 20 insertions(+), 12 deletions(-)

diff --git a/arch/riscv/include/asm/signal32.h b/arch/riscv/include/asm/signal32.h
index cda62d7eb0a5..e47bb739e61a 100644
--- a/arch/riscv/include/asm/signal32.h
+++ b/arch/riscv/include/asm/signal32.h
@@ -3,7 +3,7 @@
 #ifndef __ASM_SIGNAL32_H
 #define __ASM_SIGNAL32_H
 
-#if IS_ENABLED(CONFIG_COMPAT)
+#if IS_ENABLED(CONFIG_COMPAT) || IS_ENABLED(CONFIG_ARCH_RV64ILP32)
 int compat_setup_rt_frame(struct ksignal *ksig, sigset_t *set,
 			  struct pt_regs *regs);
 long __riscv_compat_rt_sigreturn(void);
diff --git a/arch/riscv/kernel/Makefile b/arch/riscv/kernel/Makefile
index a4583a29b28b..e8af95298e98 100644
--- a/arch/riscv/kernel/Makefile
+++ b/arch/riscv/kernel/Makefile
@@ -97,6 +97,7 @@ obj-$(CONFIG_JUMP_LABEL)	+= jump_label.o
 obj-$(CONFIG_EFI)		+= efi.o
 obj-$(CONFIG_COMPAT)		+= compat_syscall_table.o
 obj-$(CONFIG_COMPAT)		+= compat_signal.o
+obj-$(CONFIG_ARCH_RV64ILP32)	+= compat_signal.o
 
 obj-$(CONFIG_64BIT)		+= pi/
 obj-$(CONFIG_ACPI)		+= acpi.o
diff --git a/arch/riscv/kernel/signal.c b/arch/riscv/kernel/signal.c
index 1c51a6783c98..95512af927dd 100644
--- a/arch/riscv/kernel/signal.c
+++ b/arch/riscv/kernel/signal.c
@@ -277,7 +277,10 @@ static long __riscv_rt_sigreturn(void)
 
 SYSCALL_DEFINE0(rt_sigreturn)
 {
-	return __riscv_rt_sigreturn();
+	if (test_thread_flag(TIF_32BIT) && !test_thread_flag(TIF_64ILP32))
+		return __riscv_compat_rt_sigreturn();
+	else
+		return __riscv_rt_sigreturn();
 }
 
 #ifdef CONFIG_COMPAT
diff --git a/kernel/signal.c b/kernel/signal.c
index b5370fe5c198..3ac7fa4f1761 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -3390,7 +3390,7 @@ int copy_siginfo_from_user(kernel_siginfo_t *to, const siginfo_t __user *from)
 	return post_copy_siginfo_from_user(to, from);
 }
 
-#ifdef CONFIG_COMPAT
+#if IS_ENABLED(CONFIG_COMPAT) || IS_ENABLED(CONFIG_ARCH_RV64ILP32)
 /**
  * copy_siginfo_to_external32 - copy a kernel siginfo into a compat user siginfo
  * @to: compat siginfo destination
@@ -3556,6 +3556,7 @@ static int post_copy_siginfo_from_user32(kernel_siginfo_t *to,
 	return 0;
 }
 
+#ifdef CONFIG_COMPAT
 static int __copy_siginfo_from_user32(int signo, struct kernel_siginfo *to,
 				      const struct compat_siginfo __user *ufrom)
 {
@@ -3567,6 +3568,7 @@ static int __copy_siginfo_from_user32(int signo, struct kernel_siginfo *to,
 	from.si_signo = signo;
 	return post_copy_siginfo_from_user32(to, &from);
 }
+#endif /* CONFIG_COMPAT */
 
 int copy_siginfo_from_user32(struct kernel_siginfo *to,
 			     const struct compat_siginfo __user *ufrom)
@@ -3578,7 +3580,7 @@ int copy_siginfo_from_user32(struct kernel_siginfo *to,
 
 	return post_copy_siginfo_from_user32(to, &from);
 }
-#endif /* CONFIG_COMPAT */
+#endif
 
 /**
  *  do_sigtimedwait - wait for queued signals specified in @which
@@ -4279,7 +4281,7 @@ int __save_altstack(stack_t __user *uss, unsigned long sp)
 	return err;
 }
 
-#ifdef CONFIG_COMPAT
+#if IS_ENABLED(CONFIG_COMPAT) || IS_ENABLED(CONFIG_ARCH_HAS_64ILP32_KERNEL)
 static int do_compat_sigaltstack(const compat_stack_t __user *uss_ptr,
 				 compat_stack_t __user *uoss_ptr)
 {
@@ -4309,13 +4311,6 @@ static int do_compat_sigaltstack(const compat_stack_t __user *uss_ptr,
 	return ret;
 }
 
-COMPAT_SYSCALL_DEFINE2(sigaltstack,
-			const compat_stack_t __user *, uss_ptr,
-			compat_stack_t __user *, uoss_ptr)
-{
-	return do_compat_sigaltstack(uss_ptr, uoss_ptr);
-}
-
 int compat_restore_altstack(const compat_stack_t __user *uss)
 {
 	int err = do_compat_sigaltstack(uss, NULL);
@@ -4335,6 +4330,15 @@ int __compat_save_altstack(compat_stack_t __user *uss, unsigned long sp)
 }
 #endif
 
+#ifdef CONFIG_COMPAT
+COMPAT_SYSCALL_DEFINE2(sigaltstack,
+			const compat_stack_t __user *, uss_ptr,
+			compat_stack_t __user *, uoss_ptr)
+{
+	return do_compat_sigaltstack(uss_ptr, uoss_ptr);
+}
+#endif
+
 #ifdef __ARCH_WANT_SYS_SIGPENDING
 
 /**
-- 
2.36.1