[PATCH v4 08/12] arm64/tracing: fix compat syscall handling

From: Marcin Nowakowski
Date: Fri Oct 14 2016 - 04:36:02 EST


Add arch_syscall_addr for arm64 and define NR_compat_syscalls, as the
number of compat syscalls for arm64 exceeds the number defined by
NR_syscalls.
Convert the existing uses of __NR_compat_syscalls to the newly
introduced NR_compat_syscalls

Signed-off-by: Marcin Nowakowski <marcin.nowakowski@xxxxxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
Acked-by: Will Deacon <will.deacon@xxxxxxx>
---
arch/arm64/include/asm/ftrace.h | 12 +-----------
arch/arm64/include/asm/unistd.h | 2 +-
arch/arm64/include/asm/unistd32.h | 2 +-
arch/arm64/kernel/Makefile | 1 +
arch/arm64/kernel/entry.S | 2 +-
arch/arm64/kernel/ftrace.c | 16 ++++++++++++++++
arch/arm64/kernel/sys32.c | 4 ++--
7 files changed, 23 insertions(+), 16 deletions(-)

diff --git a/arch/arm64/include/asm/ftrace.h b/arch/arm64/include/asm/ftrace.h
index caa955f..b57ff7c 100644
--- a/arch/arm64/include/asm/ftrace.h
+++ b/arch/arm64/include/asm/ftrace.h
@@ -41,17 +41,7 @@ static inline unsigned long ftrace_call_adjust(unsigned long addr)

#define ftrace_return_address(n) return_address(n)

-/*
- * Because AArch32 mode does not share the same syscall table with AArch64,
- * tracing compat syscalls may result in reporting bogus syscalls or even
- * hang-up, so just do not trace them.
- * See kernel/trace/trace_syscalls.c
- *
- * x86 code says:
- * If the user really wants these, then they should use the
- * raw syscall tracepoints with filtering.
- */
-#define ARCH_TRACE_IGNORE_COMPAT_SYSCALLS
+#define ARCH_COMPAT_SYSCALL_NUMBERS_OVERLAP 1
static inline bool arch_trace_is_compat_syscall(struct pt_regs *regs)
{
return is_compat_task();
diff --git a/arch/arm64/include/asm/unistd.h b/arch/arm64/include/asm/unistd.h
index e78ac26..df56ffc 100644
--- a/arch/arm64/include/asm/unistd.h
+++ b/arch/arm64/include/asm/unistd.h
@@ -44,7 +44,7 @@
#define __ARM_NR_compat_cacheflush (__ARM_NR_COMPAT_BASE+2)
#define __ARM_NR_compat_set_tls (__ARM_NR_COMPAT_BASE+5)

-#define __NR_compat_syscalls 394
+#define NR_compat_syscalls 394
#endif

#define __ARCH_WANT_SYS_CLONE
diff --git a/arch/arm64/include/asm/unistd32.h b/arch/arm64/include/asm/unistd32.h
index b7e8ef1..0fd0909 100644
--- a/arch/arm64/include/asm/unistd32.h
+++ b/arch/arm64/include/asm/unistd32.h
@@ -812,5 +812,5 @@ __SYSCALL(__NR_pwritev2, compat_sys_pwritev2)

/*
* Please add new compat syscalls above this comment and update
- * __NR_compat_syscalls in asm/unistd.h.
+ * NR_compat_syscalls in asm/unistd.h.
*/
diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile
index 7d66bba..7ea9cd3 100644
--- a/arch/arm64/kernel/Makefile
+++ b/arch/arm64/kernel/Makefile
@@ -30,6 +30,7 @@ $(obj)/%.stub.o: $(obj)/%.o FORCE
arm64-obj-$(CONFIG_COMPAT) += sys32.o kuser32.o signal32.o \
sys_compat.o entry32.o
arm64-obj-$(CONFIG_FUNCTION_TRACER) += ftrace.o entry-ftrace.o
+arm64-obj-$(CONFIG_FTRACE_SYSCALLS) += ftrace.o
arm64-obj-$(CONFIG_MODULES) += arm64ksyms.o module.o
arm64-obj-$(CONFIG_ARM64_MODULE_PLTS) += module-plts.o
arm64-obj-$(CONFIG_PERF_EVENTS) += perf_regs.o perf_callchain.o
diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
index 223d54a..9fb7ad1 100644
--- a/arch/arm64/kernel/entry.S
+++ b/arch/arm64/kernel/entry.S
@@ -518,7 +518,7 @@ el0_svc_compat:
*/
adrp stbl, compat_sys_call_table // load compat syscall table pointer
uxtw scno, w7 // syscall number in w7 (r7)
- mov sc_nr, #__NR_compat_syscalls
+ mov sc_nr, #NR_compat_syscalls
b el0_svc_naked

.align 6
diff --git a/arch/arm64/kernel/ftrace.c b/arch/arm64/kernel/ftrace.c
index 40ad08a..75d010f 100644
--- a/arch/arm64/kernel/ftrace.c
+++ b/arch/arm64/kernel/ftrace.c
@@ -176,4 +176,20 @@ int ftrace_disable_ftrace_graph_caller(void)
return ftrace_modify_graph_caller(false);
}
#endif /* CONFIG_DYNAMIC_FTRACE */
+
#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
+
+#if (defined CONFIG_FTRACE_SYSCALLS) && (defined CONFIG_COMPAT)
+
+extern const void *sys_call_table[];
+extern const void *compat_sys_call_table[];
+
+unsigned long __init arch_syscall_addr(int nr, bool compat)
+{
+ if (compat)
+ return (unsigned long)compat_sys_call_table[nr];
+
+ return (unsigned long)sys_call_table[nr];
+}
+
+#endif /* CONFIG_FTRACE_SYSCALLS && CONFIG_COMPAT */
diff --git a/arch/arm64/kernel/sys32.c b/arch/arm64/kernel/sys32.c
index a40b134..ae7a992 100644
--- a/arch/arm64/kernel/sys32.c
+++ b/arch/arm64/kernel/sys32.c
@@ -46,7 +46,7 @@ asmlinkage long compat_sys_mmap2_wrapper(void);
* The sys_call_table array must be 4K aligned to be accessible from
* kernel/entry.S.
*/
-void * const compat_sys_call_table[__NR_compat_syscalls] __aligned(4096) = {
- [0 ... __NR_compat_syscalls - 1] = sys_ni_syscall,
+void * const compat_sys_call_table[NR_compat_syscalls] __aligned(4096) = {
+ [0 ... NR_compat_syscalls - 1] = sys_ni_syscall,
#include <asm/unistd32.h>
};
--
2.7.4