On 6/10/20 8:37 PM, Oleg Nesterov wrote:

Hi,

looks like this patch was forgotten.

yep, I missed this. But mpe did have comments for the patch.

https://lkml.org/lkml/2019/9/19/107

Maddy

Do you think this should be fixed or should we document that
PTRACE_GETREGS is not consistent with PTRACE_PEEKUSER on ppc64?


On 09/17, Oleg Nesterov wrote:

quoted

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 <redacted>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
---
  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