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SubjectRe: [PATCH v3 2/2] powerpc/ptrace: Hard wire PT_SOFTE value to 1 in gpr_get() too

Quoting Oleg Nesterov <oleg@redhat.com>:

> 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 the user-regs-peekpoke test
> from https://sourceware.org/systemtap/wiki/utrace/tests/
>
> Reported-by: Jan Kratochvil <jan.kratochvil@redhat.com>
> Signed-off-by: Oleg Nesterov <oleg@redhat.com>
> ---
> arch/powerpc/kernel/ptrace/ptrace-tm.c | 8 +++++++-
> arch/powerpc/kernel/ptrace/ptrace-view.c | 8 +++++++-
> 2 files changed, 14 insertions(+), 2 deletions(-)
>

I think the following should work, and not require the first patch
(compile tested only).

diff --git a/arch/powerpc/kernel/ptrace/ptrace-tm.c
b/arch/powerpc/kernel/ptrace/ptrace-tm.c
index 54f2d076206f..f779b3bc0279 100644
--- a/arch/powerpc/kernel/ptrace/ptrace-tm.c
+++ b/arch/powerpc/kernel/ptrace/ptrace-tm.c
@@ -104,8 +104,14 @@ int tm_cgpr_get(struct task_struct *target, const
struct user_regset *regset,
offsetof(struct pt_regs, msr) + sizeof(long));

membuf_write(&to, &target->thread.ckpt_regs.orig_gpr3,
- sizeof(struct user_pt_regs) -
- offsetof(struct pt_regs, orig_gpr3));
+ offsetof(struct pt_regs, softe) - offsetof(struct pt_regs,
orig_gpr3));
+ membuf_store(&to, 1UL);
+
+ BUILD_BUG_ON(offsetof(struct pt_regs, trap) !=
+ offsetof(struct pt_regs, softe) + sizeof(long));
+
+ membuf_write(&to, &target->thread.ckpt_regs.trap,
+ sizeof(struct user_pt_regs) - offsetof(struct pt_regs, trap));
return membuf_zero(&to, ELF_NGREG * sizeof(unsigned long) -
sizeof(struct user_pt_regs));
}
diff --git a/arch/powerpc/kernel/ptrace/ptrace-view.c
b/arch/powerpc/kernel/ptrace/ptrace-view.c
index 7e6478e7ed07..736bfbf33890 100644
--- a/arch/powerpc/kernel/ptrace/ptrace-view.c
+++ b/arch/powerpc/kernel/ptrace/ptrace-view.c
@@ -234,9 +234,21 @@ 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
+ membuf_write(&to, &target->thread.regs->orig_gpr3,
+ offsetof(struct pt_regs, softe) - offsetof(struct pt_regs,
orig_gpr3));
+ membuf_store(&to, 1UL);
+
+ BUILD_BUG_ON(offsetof(struct pt_regs, trap) !=
+ offsetof(struct pt_regs, softe) + sizeof(long));
+
+ membuf_write(&to, &target->thread.regs->trap,
+ sizeof(struct user_pt_regs) - offsetof(struct pt_regs, trap));
+#else
membuf_write(&to, &target->thread.regs->orig_gpr3,
sizeof(struct user_pt_regs) -
offsetof(struct pt_regs, orig_gpr3));
+#endif
return membuf_zero(&to, ELF_NGREG * sizeof(unsigned long) -
sizeof(struct user_pt_regs));
}
---
Christophe
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