linux-kernel - [PATCH v3 2/2] powerpc/ptrace: Hard wire PT_SOFTE value to 1 in gpr

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Date:   Thu, 19 Nov 2020 17:02:47 +0100
From:   Oleg Nesterov <oleg@...hat.com>
To:     Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Madhavan Srinivasan <maddy@...ux.vnet.ibm.com>,
        Michael Ellerman <mpe@...erman.id.au>,
        Paul Mackerras <paulus@...ba.org>
Cc:     Al Viro <viro@...iv.linux.org.uk>,
        "Aneesh Kumar K.V" <aneesh.kumar@...ux.ibm.com>,
        Christophe Leroy <christophe.leroy@....fr>,
        Jan Kratochvil <jan.kratochvil@...hat.com>,
        Nicholas Piggin <npiggin@...il.com>,
        linuxppc-dev@...ts.ozlabs.org, linux-kernel@...r.kernel.org
Subject: [PATCH v3 2/2] powerpc/ptrace: Hard wire PT_SOFTE value to 1 in
 gpr_get() too

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@...hat.com>
Signed-off-by: Oleg Nesterov <oleg@...hat.com>
---
 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));
+#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));
+#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));
 }
-- 
2.25.1.362.g51ebf55