[PATCH 1/3] libbpf: Fix accessing the syscall argument on powerpc

[Saket Kumar Bhaskar <skb99@linux.ibm.com>]

Since commit 7e92e01b7245 ("powerpc: Provide syscall wrapper"), powerpc
selects ARCH_HAS_SYSCALL_WRAPPER so let's use the generic implementation
of PT_REGS_SYSCALL_REGS().

Also, allow overriding PT_REGS_PARM1{_CORE}_SYSCALL for powerpc as
powerpc needs orig_gpr3, similar to s390 and arm64.

Signed-off-by: Saket Kumar Bhaskar <skb99@linux.ibm.com>
---
 tools/lib/bpf/bpf_tracing.h | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/tools/lib/bpf/bpf_tracing.h b/tools/lib/bpf/bpf_tracing.h
index a8f6cd4841b0..933e1dab6c8f 100644
--- a/tools/lib/bpf/bpf_tracing.h
+++ b/tools/lib/bpf/bpf_tracing.h
@@ -287,6 +287,10 @@ struct pt_regs___arm64 {
  * section "Function Calling Sequence")
  */
 
+struct pt_regs___powerpc {
+	unsigned long orig_gpr3;
+} __attribute__((preserve_access_index));
+
 #define __PT_PARM1_REG gpr[3]
 #define __PT_PARM2_REG gpr[4]
 #define __PT_PARM3_REG gpr[5]
@@ -296,8 +300,6 @@ struct pt_regs___arm64 {
 #define __PT_PARM7_REG gpr[9]
 #define __PT_PARM8_REG gpr[10]
 
-/* powerpc does not select ARCH_HAS_SYSCALL_WRAPPER. */
-#define PT_REGS_SYSCALL_REGS(ctx) ctx
 #define __PT_PARM1_SYSCALL_REG orig_gpr3
 #define __PT_PARM2_SYSCALL_REG __PT_PARM2_REG
 #define __PT_PARM3_SYSCALL_REG __PT_PARM3_REG
@@ -307,6 +309,9 @@ struct pt_regs___arm64 {
 #if !defined(__arch64__)
 #define __PT_PARM7_SYSCALL_REG __PT_PARM7_REG /* only powerpc (not powerpc64) */
 #endif
+#define PT_REGS_PARM1_SYSCALL(x) (((const struct pt_regs___powerpc *)(x))->orig_gpr3)
+#define PT_REGS_PARM1_CORE_SYSCALL(x) \
+	BPF_CORE_READ((const struct pt_regs___powerpc *)(x), __PT_PARM1_SYSCALL_REG)
 
 #define __PT_RET_REG regs[31]
 #define __PT_FP_REG __unsupported__
-- 
2.43.5