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

From: Christophe Leroy
Date: Thu Nov 19 2020 - 12:18:50 EST




Le 19/11/2020 à 17:02, Oleg Nesterov a écrit :
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@xxxxxxxxxx>
Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>
---
arch/powerpc/kernel/ptrace/ptrace-tm.c | 8 +++++++-
arch/powerpc/kernel/ptrace/ptrace-view.c | 8 +++++++-
2 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/kernel/ptrace/ptrace-tm.c b/arch/powerpc/kernel/ptrace/ptrace-tm.c
index f8fcbd85d4cb..d0d339f86e61 100644
--- a/arch/powerpc/kernel/ptrace/ptrace-tm.c
+++ b/arch/powerpc/kernel/ptrace/ptrace-tm.c
@@ -87,6 +87,10 @@ int tm_cgpr_get(struct task_struct *target, const struct user_regset *regset,
struct membuf to)
{
struct membuf to_msr = membuf_at(&to, offsetof(struct pt_regs, msr));
+#ifdef CONFIG_PPC64
+ struct membuf to_softe = membuf_at(&to,
+ offsetof(struct pt_regs, softe));

Should fit on a single line I think.

+#endif
if (!cpu_has_feature(CPU_FTR_TM))
return -ENODEV;
@@ -102,7 +106,9 @@ int tm_cgpr_get(struct task_struct *target, const struct user_regset *regset,
sizeof(struct user_pt_regs));
membuf_store(&to_msr, get_user_ckpt_msr(target));
-
+#ifdef CONFIG_PPC64
+ membuf_store(&to_softe, 0x1ul);
+#endif
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 39686ede40b3..f554ccfcbfae 100644
--- a/arch/powerpc/kernel/ptrace/ptrace-view.c
+++ b/arch/powerpc/kernel/ptrace/ptrace-view.c
@@ -218,6 +218,10 @@ static int gpr_get(struct task_struct *target, const struct user_regset *regset,
struct membuf to)
{
struct membuf to_msr = membuf_at(&to, offsetof(struct pt_regs, msr));
+#ifdef CONFIG_PPC64
+ struct membuf to_softe = membuf_at(&to,
+ offsetof(struct pt_regs, softe));

Should fit on a single line I think.

+#endif
int i;
if (target->thread.regs == NULL)
@@ -233,7 +237,9 @@ static int gpr_get(struct task_struct *target, const struct user_regset *regset,
sizeof(struct user_pt_regs));
membuf_store(&to_msr, get_user_msr(target));
-
+#ifdef CONFIG_PPC64
+ membuf_store(&to_softe, 0x1ul);
+#endif
return membuf_zero(&to, ELF_NGREG * sizeof(unsigned long) -
sizeof(struct user_pt_regs));
}


Christophe