From: Ilya Leoshkevich iii@linux.ibm.com
[ Upstream commit fbca4a2f649730b67488a8b36140ce4d2cf13c63 ]
On arm64, the first syscall argument should be accessed via orig_x0 (see arch/arm64/include/asm/syscall.h). Currently regs[0] is used instead, leading to bpf_syscall_macro test failure.
orig_x0 cannot be added to struct user_pt_regs, since its layout is a part of the ABI. Therefore provide access to it only through PT_REGS_PARM1_CORE_SYSCALL() by using a struct pt_regs flavor.
Reported-by: Heiko Carstens hca@linux.ibm.com Signed-off-by: Ilya Leoshkevich iii@linux.ibm.com Signed-off-by: Andrii Nakryiko andrii@kernel.org Link: https://lore.kernel.org/bpf/20220209021745.2215452-10-iii@linux.ibm.com Signed-off-by: Sasha Levin sashal@kernel.org --- tools/lib/bpf/bpf_tracing.h | 6 ++++++ 1 file changed, 6 insertions(+)
diff --git a/tools/lib/bpf/bpf_tracing.h b/tools/lib/bpf/bpf_tracing.h index d40b87c0e4b9..ad62c17919cf 100644 --- a/tools/lib/bpf/bpf_tracing.h +++ b/tools/lib/bpf/bpf_tracing.h @@ -140,6 +140,10 @@
#elif defined(bpf_target_arm64)
+struct pt_regs___arm64 { + unsigned long orig_x0; +}; + /* arm64 provides struct user_pt_regs instead of struct pt_regs to userspace */ #define __PT_REGS_CAST(x) ((const struct user_pt_regs *)(x)) #define __PT_PARM1_REG regs[0] @@ -152,6 +156,8 @@ #define __PT_RC_REG regs[0] #define __PT_SP_REG sp #define __PT_IP_REG pc +#define PT_REGS_PARM1_SYSCALL(x) ({ _Pragma("GCC error "use PT_REGS_PARM1_CORE_SYSCALL() instead""); 0l; }) +#define PT_REGS_PARM1_CORE_SYSCALL(x) BPF_CORE_READ((const struct pt_regs___arm64 *)(x), orig_x0)
#elif defined(bpf_target_mips)