| Message ID | 20220209021745.2215452-11-iii@linux.ibm.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 1f22a6f9f9a0f50218a11a0554709fd34a821fa3 |
| Delegated to: | BPF |
| Headers | show |
| Series | Fix accessing syscall arguments | expand |
On Tue, Feb 8, 2022 at 6:18 PM Ilya Leoshkevich <iii@linux.ibm.com> wrote: > > On s390, the first syscall argument should be accessed via orig_gpr2 > (see arch/s390/include/asm/syscall.h). Currently gpr[2] is used > instead, leading to bpf_syscall_macro test failure. > > orig_gpr2 cannot be added to 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: Andrii Nakryiko <andrii@kernel.org> > Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com> > --- > tools/lib/bpf/bpf_tracing.h | 10 ++++++++++ > 1 file changed, 10 insertions(+) > > diff --git a/tools/lib/bpf/bpf_tracing.h b/tools/lib/bpf/bpf_tracing.h > index 928f85f7961c..0e0414801457 100644 > --- a/tools/lib/bpf/bpf_tracing.h > +++ b/tools/lib/bpf/bpf_tracing.h > @@ -114,9 +114,19 @@ > > #elif defined(bpf_target_s390) > > +struct pt_regs___s390 { > + unsigned long orig_gpr2; > +} __attribute__((preserve_access_index)); > + > /* s390 provides user_pt_regs instead of struct pt_regs to userspace */ > #define __PT_REGS_CAST(x) ((const user_pt_regs *)(x)) > #define __PT_PARM1_REG gprs[2] > +#define PT_REGS_PARM1_SYSCALL(x) ({ \ > + _Pragma("GCC error \"PT_REGS_PARM1_SYSCALL() is not supported on s390, use PT_REGS_PARM1_CORE_SYSCALL() instead\""); \ > + 0l; \ > +}) > +#define PT_REGS_PARM1_CORE_SYSCALL(x) \ > + BPF_CORE_READ((const struct pt_regs___s390 *)(x), orig_gpr2) same manipulations as on previous patch > #define __PT_PARM2_REG gprs[3] > #define __PT_PARM3_REG gprs[4] > #define __PT_PARM4_REG gprs[5] > -- > 2.34.1 >
diff --git a/tools/lib/bpf/bpf_tracing.h b/tools/lib/bpf/bpf_tracing.h index 928f85f7961c..0e0414801457 100644 --- a/tools/lib/bpf/bpf_tracing.h +++ b/tools/lib/bpf/bpf_tracing.h @@ -114,9 +114,19 @@ #elif defined(bpf_target_s390) +struct pt_regs___s390 { + unsigned long orig_gpr2; +} __attribute__((preserve_access_index)); + /* s390 provides user_pt_regs instead of struct pt_regs to userspace */ #define __PT_REGS_CAST(x) ((const user_pt_regs *)(x)) #define __PT_PARM1_REG gprs[2] +#define PT_REGS_PARM1_SYSCALL(x) ({ \ + _Pragma("GCC error \"PT_REGS_PARM1_SYSCALL() is not supported on s390, use PT_REGS_PARM1_CORE_SYSCALL() instead\""); \ + 0l; \ +}) +#define PT_REGS_PARM1_CORE_SYSCALL(x) \ + BPF_CORE_READ((const struct pt_regs___s390 *)(x), orig_gpr2) #define __PT_PARM2_REG gprs[3] #define __PT_PARM3_REG gprs[4] #define __PT_PARM4_REG gprs[5]
On s390, the first syscall argument should be accessed via orig_gpr2 (see arch/s390/include/asm/syscall.h). Currently gpr[2] is used instead, leading to bpf_syscall_macro test failure. orig_gpr2 cannot be added to 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: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com> --- tools/lib/bpf/bpf_tracing.h | 10 ++++++++++ 1 file changed, 10 insertions(+)