libbpf: Add ARC support to bpf_tracing.h

Add PT_REGS macros suitable for ARCompact and ARCv2.
Signed-off-by: Vladimir Isaev <isaev@synopsys.com>
Signed-off-by: Sergey Matyukevich <geomatsi@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Song Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/bpf/20220408224442.599566-1-geomatsi@gmail.com

tools/include/uapi/asm/bpf_perf_event.h

 #if defined(__aarch64__)
 #include "../../arch/arm64/include/uapi/asm/bpf_perf_event.h"
+#elif defined(__arc__)
+#include "../../arch/arc/include/uapi/asm/bpf_perf_event.h"
 #elif defined(__s390__)
 #include "../../arch/s390/include/uapi/asm/bpf_perf_event.h"
 #elif defined(__riscv)

tools/lib/bpf/bpf_tracing.h

@@ -27,6 +27,9 @@
 #elif defined(__TARGET_ARCH_riscv)
 	#define bpf_target_riscv
 	#define bpf_target_defined
+#elif defined(__TARGET_ARCH_arc)
+	#define bpf_target_arc
+	#define bpf_target_defined
 #else
 
 /* Fall back to what the compiler says */
@@ -54,6 +57,9 @@
 #elif defined(__riscv) && __riscv_xlen == 64
 	#define bpf_target_riscv
 	#define bpf_target_defined
+#elif defined(__arc__)
+	#define bpf_target_arc
+	#define bpf_target_defined
 #endif /* no compiler target */
 
 #endif
@@ -233,6 +239,23 @@ struct pt_regs___arm64 {
 /* riscv does not select ARCH_HAS_SYSCALL_WRAPPER. */
 #define PT_REGS_SYSCALL_REGS(ctx) ctx
 
+#elif defined(bpf_target_arc)
+
+/* arc provides struct user_pt_regs instead of struct pt_regs to userspace */
+#define __PT_REGS_CAST(x) ((const struct user_regs_struct *)(x))
+#define __PT_PARM1_REG scratch.r0
+#define __PT_PARM2_REG scratch.r1
+#define __PT_PARM3_REG scratch.r2
+#define __PT_PARM4_REG scratch.r3
+#define __PT_PARM5_REG scratch.r4
+#define __PT_RET_REG scratch.blink
+#define __PT_FP_REG __unsupported__
+#define __PT_RC_REG scratch.r0
+#define __PT_SP_REG scratch.sp
+#define __PT_IP_REG scratch.ret
+/* arc does not select ARCH_HAS_SYSCALL_WRAPPER. */
+#define PT_REGS_SYSCALL_REGS(ctx) ctx
+
 #endif
 
 #if defined(bpf_target_defined)