From 73d6eb48d26930f0cbdc8bf1ccb0ad964e7d2b90 Mon Sep 17 00:00:00 2001
From: Ilya Leoshkevich <iii@linux.ibm.com>
Date: Wed, 22 Jul 2020 23:58:54 +0200
Subject: [PATCH] s390: enable HAVE_FUNCTION_ERROR_INJECTION
This kernel feature is required for enabling BPF_KPROBE_OVERRIDE.
Define override_function_with_return() and regs_set_return_value()
functions, and fix compile errors in syscall_wrapper.h.
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
---
arch/s390/Kconfig | 1 +
arch/s390/include/asm/ptrace.h | 5 +++++
arch/s390/include/asm/syscall_wrapper.h | 6 +++---
arch/s390/lib/Makefile | 2 ++
arch/s390/lib/error-inject.c | 14 ++++++++++++++
5 files changed, 25 insertions(+), 3 deletions(-)
create mode 100644 arch/s390/lib/error-inject.c
diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index d95d323cf213..9cfd8de907cb 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -145,6 +145,7 @@ config S390
select HAVE_EFFICIENT_UNALIGNED_ACCESS
select HAVE_FENTRY
select HAVE_FTRACE_MCOUNT_RECORD
+ select HAVE_FUNCTION_ERROR_INJECTION
select HAVE_FUNCTION_GRAPH_TRACER
select HAVE_FUNCTION_TRACER
select HAVE_FUTEX_CMPXCHG if FUTEX
diff --git a/arch/s390/include/asm/ptrace.h b/arch/s390/include/asm/ptrace.h
index f009a13afe71..16b3e4396312 100644
--- a/arch/s390/include/asm/ptrace.h
+++ b/arch/s390/include/asm/ptrace.h
@@ -184,5 +184,10 @@ static inline unsigned long kernel_stack_pointer(struct pt_regs *regs)
return regs->gprs[15];
}
+static inline void regs_set_return_value(struct pt_regs *regs, unsigned long rc)
+{
+ regs->gprs[2] = rc;
+}
+
#endif /* __ASSEMBLY__ */
#endif /* _S390_PTRACE_H */
diff --git a/arch/s390/include/asm/syscall_wrapper.h b/arch/s390/include/asm/syscall_wrapper.h
index 3c3d6fe8e2f0..1320f4213d80 100644
--- a/arch/s390/include/asm/syscall_wrapper.h
+++ b/arch/s390/include/asm/syscall_wrapper.h
@@ -30,7 +30,7 @@
})
#define __S390_SYS_STUBx(x, name, ...) \
- asmlinkage long __s390_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__))\
+ asmlinkage long __s390_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__));\
ALLOW_ERROR_INJECTION(__s390_sys##name, ERRNO); \
asmlinkage long __s390_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__))\
{ \
@@ -46,7 +46,7 @@
#define COMPAT_SYSCALL_DEFINE0(sname) \
SYSCALL_METADATA(_##sname, 0); \
asmlinkage long __s390_compat_sys_##sname(void); \
- ALLOW_ERROR_INJECTION(__s390_compat__sys_##sname, ERRNO); \
+ ALLOW_ERROR_INJECTION(__s390_compat_sys_##sname, ERRNO); \
asmlinkage long __s390_compat_sys_##sname(void)
#define SYSCALL_DEFINE0(sname) \
@@ -72,7 +72,7 @@
asmlinkage long __s390_compat_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__)); \
asmlinkage long __s390_compat_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__)) \
__attribute__((alias(__stringify(__se_compat_sys##name)))); \
- ALLOW_ERROR_INJECTION(compat_sys##name, ERRNO); \
+ ALLOW_ERROR_INJECTION(__s390_compat_sys##name, ERRNO); \
static inline long __do_compat_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__));\
asmlinkage long __se_compat_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__)); \
asmlinkage long __se_compat_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__)) \
diff --git a/arch/s390/lib/Makefile b/arch/s390/lib/Makefile
index 28fd66d558ff..678333936f78 100644
--- a/arch/s390/lib/Makefile
+++ b/arch/s390/lib/Makefile
@@ -14,3 +14,5 @@ KASAN_SANITIZE_uaccess.o := n
obj-$(CONFIG_S390_UNWIND_SELFTEST) += test_unwind.o
CFLAGS_test_unwind.o += -fno-optimize-sibling-calls
+
+lib-$(CONFIG_FUNCTION_ERROR_INJECTION) += error-inject.o
diff --git a/arch/s390/lib/error-inject.c b/arch/s390/lib/error-inject.c
new file mode 100644
index 000000000000..8c9d4da87eef
--- /dev/null
+++ b/arch/s390/lib/error-inject.c
@@ -0,0 +1,14 @@
+// SPDX-License-Identifier: GPL-2.0+
+#include <asm/ptrace.h>
+#include <linux/error-injection.h>
+#include <linux/kprobes.h>
+
+void override_function_with_return(struct pt_regs *regs)
+{
+ /*
+ * Emulate 'br 14'. 'regs' is captured by kprobes on entry to some
+ * kernel function.
+ */
+ regs->psw.addr = regs->gprs[14];
+}
+NOKPROBE_SYMBOL(override_function_with_return);
--
2.30.9