From: "Dmitry V. Levin" <ldv@altlinux.org>
To: Arnd Bergmann <arnd@arndb.de>, Oleg Nesterov <oleg@redhat.com>,
Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Elvira Khabirova <lineprinter@altlinux.org>,
Eugene Syromyatnikov <esyr@redhat.com>,
linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH v6 02/27] asm-generic/syscall.h: turn syscall_[gs]et_arguments into wrappers
Date: Thu, 13 Dec 2018 20:21:18 +0300 [thread overview]
Message-ID: <20181213172118.GB6024@altlinux.org> (raw)
In-Reply-To: 20181213171833.GA5240@altlinux.org
Add a generic wrapper syscall_get_arguments() that checks
its arguments and calls arch-specific __syscall_get_arguments().
Likewise, add a generic wrapper syscall_set_arguments() that checks
its arguments and calls arch-specific __syscall_set_arguments().
This is the first step on the way of getting rid of BUGs, BUG_ONs,
and replicated error checks in arch-specific asm/syscall.h files.
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Elvira Khabirova <lineprinter@altlinux.org>
Cc: Eugene Syromyatnikov <esyr@redhat.com>
Cc: linux-arch@vger.kernel.org
Signed-off-by: Dmitry V. Levin <ldv@altlinux.org>
---
Notes:
v6: initial revision
include/asm-generic/syscall.h | 47 +++++++++++++++++++++++++++++++++--
1 file changed, 45 insertions(+), 2 deletions(-)
diff --git a/include/asm-generic/syscall.h b/include/asm-generic/syscall.h
index 9863a5f8fbe8..fdefe27fa63f 100644
--- a/include/asm-generic/syscall.h
+++ b/include/asm-generic/syscall.h
@@ -122,10 +122,34 @@ syscall_set_return_value(struct task_struct *task, struct pt_regs *regs,
* entry to a system call, due to %TIF_SYSCALL_TRACE or %TIF_SYSCALL_AUDIT.
* It's invalid to call this with @i + @n > 6; we only support system calls
* taking up to 6 arguments.
+ *
+ * This function is a wrapper around arch-specific __syscall_get_arguments.
*/
static void
+__syscall_get_arguments(struct task_struct *task, struct pt_regs *regs,
+ unsigned int i, unsigned int n, unsigned long *args);
+
+static inline void
syscall_get_arguments(struct task_struct *task, struct pt_regs *regs,
- unsigned int i, unsigned int n, unsigned long *args);
+ unsigned int i, unsigned int n, unsigned long *args)
+{
+ /*
+ * Ideally there should have been a BUILD_BUG_ON(i + n > 6)
+ * instead of these checks because it is a "cannot happen"
+ * kind of assertion.
+ */
+ if (WARN_ON_ONCE(i > 6)) {
+ memset(args, 0, n * sizeof(args[0]));
+ return;
+ }
+ if (WARN_ON_ONCE(n > 6 - i)) {
+ unsigned int extra = n - (6 - i);
+
+ n = 6 - i;
+ memset(&args[n], 0, extra * sizeof(args[0]));
+ }
+ __syscall_get_arguments(task, regs, i, n, args);
+}
/**
* syscall_set_arguments - change system call parameter value
@@ -143,11 +167,30 @@ syscall_get_arguments(struct task_struct *task, struct pt_regs *regs,
* entry to a system call, due to %TIF_SYSCALL_TRACE or %TIF_SYSCALL_AUDIT.
* It's invalid to call this with @i + @n > 6; we only support system calls
* taking up to 6 arguments.
+ *
+ * This function is a wrapper around arch-specific __syscall_set_arguments.
*/
static void
+__syscall_set_arguments(struct task_struct *task, struct pt_regs *regs,
+ unsigned int i, unsigned int n,
+ const unsigned long *args);
+
+static inline void
syscall_set_arguments(struct task_struct *task, struct pt_regs *regs,
unsigned int i, unsigned int n,
- const unsigned long *args);
+ const unsigned long *args)
+{
+ /*
+ * Ideally there should have been a BUILD_BUG_ON(i + n > 6)
+ * instead of these checks because it is a "cannot happen"
+ * kind of assertion.
+ */
+ if (WARN_ON_ONCE(i > 6))
+ return;
+ if (WARN_ON_ONCE(n > 6 - i))
+ n = 6 - i;
+ __syscall_set_arguments(task, regs, i, n, args);
+}
/**
* syscall_get_arch - return the AUDIT_ARCH for the current system call
--
ldv
next prev parent reply other threads:[~2018-12-13 17:21 UTC|newest]
Thread overview: 8+ 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 17:21 ` [PATCH v6 01/27] asm-generic/syscall.h: prepare for inclusion by other files Dmitry V. Levin
2018-12-13 17:21 ` Dmitry V. Levin
2018-12-13 17:21 ` Dmitry V. Levin [this message]
2018-12-13 17:21 ` [PATCH v6 02/27] asm-generic/syscall.h: turn syscall_[gs]et_arguments into wrappers Dmitry V. Levin
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
2018-12-14 20:15 ` [PATCH v6 00/27] ptrace: add PTRACE_GET_SYSCALL_INFO request Paul Moore
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