From: "Dmitry V. Levin" <ldv@altlinux•org>
To: linux-kernel@vger•kernel.org
Cc: Elvira Khabirova <lineprinter@altlinux•org>,
linuxppc-dev@lists•ozlabs.org, Oleg Nesterov <oleg@redhat•com>,
Eugene Syromyatnikov <esyr@redhat•com>
Subject: [PATCH v6 25/27] powerpc/ptrace: replace ptrace_report_syscall() with a tracehook call
Date: Thu, 13 Dec 2018 20:24:30 +0300 [thread overview]
Message-ID: <20181213172430.GY6024@altlinux.org> (raw)
In-Reply-To: 20181213171833.GA5240@altlinux.org
From: Elvira Khabirova <lineprinter@altlinux•org>
Arch code should use tracehook_*() helpers, as documented in
include/linux/tracehook.h, ptrace_report_syscall() is not expected to
be used outside that file.
The patch does not look very nice, but at least it is correct
and opens the way for PTRACE_GET_SYSCALL_INFO API.
Co-authored-by: Dmitry V. Levin <ldv@altlinux•org>
Fixes: 5521eb4bca2d ("powerpc/ptrace: Add support for PTRACE_SYSEMU")
Signed-off-by: Elvira Khabirova <lineprinter@altlinux•org>
Signed-off-by: Dmitry V. Levin <ldv@altlinux•org>
[mpe: Take this as a minimal fix for 4.20, we'll rework it later]
Signed-off-by: Michael Ellerman <mpe@ellerman•id.au>
---
Notes:
v6: this is the fix that was taken into powerpc tree
v5: reverted to a simple approach, compile- and run-tested
v4: rewritten to call tracehook_report_syscall_entry() once, compile-tested
v3: add a descriptive comment
v2: explicitly ignore tracehook_report_syscall_entry() return code
arch/powerpc/kernel/ptrace.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/kernel/ptrace.c b/arch/powerpc/kernel/ptrace.c
index afb819f4ca68..714c3480c52d 100644
--- a/arch/powerpc/kernel/ptrace.c
+++ b/arch/powerpc/kernel/ptrace.c
@@ -3266,12 +3266,17 @@ long do_syscall_trace_enter(struct pt_regs *regs)
user_exit();
if (test_thread_flag(TIF_SYSCALL_EMU)) {
- ptrace_report_syscall(regs);
/*
+ * A nonzero return code from tracehook_report_syscall_entry()
+ * tells us to prevent the syscall execution, but we are not
+ * going to execute it anyway.
+ *
* Returning -1 will skip the syscall execution. We want to
* avoid clobbering any register also, thus, not 'gotoing'
* skip label.
*/
+ if (tracehook_report_syscall_entry(regs))
+ ;
return -1;
}
--
ldv
next prev parent reply other threads:[~2018-12-13 17:27 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-13 17:18 [PATCH v6 00/27] ptrace: add PTRACE_GET_SYSCALL_INFO request Dmitry V. Levin
2018-12-13 17:23 ` [PATCH v6 18/27] powerpc: define syscall_get_error() Dmitry V. Levin
2018-12-18 12:36 ` powerpc syscall_set_return_value() is confused (was Re: [PATCH v6 18/27] powerpc: define syscall_get_error()) Michael Ellerman
2018-12-13 17:24 ` [PATCH v6 24/27] syscall_get_arch: add "struct task_struct *" argument Dmitry V. Levin
2018-12-13 17:24 ` Dmitry V. Levin [this message]
2018-12-14 20:15 ` [PATCH v6 00/27] ptrace: add PTRACE_GET_SYSCALL_INFO request Paul Moore
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