[PATCH? v2] powerpc: Hard wire PT_SOFTE value to 1 in gpr_get() too

From: Oleg Nesterov
Date: Tue Sep 17 2019 - 10:38:01 EST


I don't have a ppc machine, this patch wasn't even compile tested,
could you please review?

The commit a8a4b03ab95f ("powerpc: Hard wire PT_SOFTE value to 1 in
ptrace & signals") changed ptrace_get_reg(PT_SOFTE) to report 0x1,
but PTRACE_GETREGS still copies pt_regs->softe as is.

This is not consistent and this breaks
http://sourceware.org/systemtap/wiki/utrace/tests/user-regs-peekpoke

Reported-by: Jan Kratochvil <jan.kratochvil@xxxxxxxxxx>
Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>
---
arch/powerpc/kernel/ptrace.c | 25 +++++++++++++++++++++++++
1 file changed, 25 insertions(+)

diff --git a/arch/powerpc/kernel/ptrace.c b/arch/powerpc/kernel/ptrace.c
index 8c92feb..291acfb 100644
--- a/arch/powerpc/kernel/ptrace.c
+++ b/arch/powerpc/kernel/ptrace.c
@@ -363,11 +363,36 @@ static int gpr_get(struct task_struct *target, const struct user_regset *regset,
BUILD_BUG_ON(offsetof(struct pt_regs, orig_gpr3) !=
offsetof(struct pt_regs, msr) + sizeof(long));

+#ifdef CONFIG_PPC64
+ if (!ret)
+ ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
+ &target->thread.regs->orig_gpr3,
+ offsetof(struct pt_regs, orig_gpr3),
+ offsetof(struct pt_regs, softe));
+
+ if (!ret) {
+ unsigned long softe = 0x1;
+ ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf, &softe,
+ offsetof(struct pt_regs, softe),
+ offsetof(struct pt_regs, softe) +
+ sizeof(softe));
+ }
+
+ BUILD_BUG_ON(offsetof(struct pt_regs, trap) !=
+ offsetof(struct pt_regs, softe) + sizeof(long));
+
+ if (!ret)
+ ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
+ &target->thread.regs->trap,
+ offsetof(struct pt_regs, trap),
+ sizeof(struct user_pt_regs));
+#else
if (!ret)
ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
&target->thread.regs->orig_gpr3,
offsetof(struct pt_regs, orig_gpr3),
sizeof(struct user_pt_regs));
+#endif
if (!ret)
ret = user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
sizeof(struct user_pt_regs), -1);
--
2.5.0