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Message-Id: <1450729600-9732-1-git-send-email-mic@digikod.net>
Date: Mon, 21 Dec 2015 21:26:40 +0100
From: Mickaël Salaün <mic@...ikod.net>
To: linux-kernel@...r.kernel.org
Cc: Mickaël Salaün <mic@...ikod.net>,
Jonathan Corbet <corbet@....net>,
Jeff Dike <jdike@...toit.com>,
Richard Weinberger <richard@....at>,
Thomas Gleixner <tglx@...utronix.de>,
Ingo Molnar <mingo@...hat.com>,
"H . Peter Anvin" <hpa@...or.com>, x86@...nel.org,
Kees Cook <keescook@...omium.org>,
Andy Lutomirski <luto@...capital.net>,
Will Drewry <wad@...omium.org>,
Shuah Khan <shuahkh@....samsung.com>,
Chris Metcalf <cmetcalf@...hip.com>,
Michael Ellerman <mpe@...erman.id.au>,
Andrew Morton <akpm@...ux-foundation.org>,
James Hogan <james.hogan@...tec.com>,
Thomas Meyer <thomas@...3r.de>,
Nicolas Iooss <nicolas.iooss_linux@....org>,
Anton Ivanov <aivanov@...cade.com>, linux-doc@...r.kernel.org,
user-mode-linux-devel@...ts.sourceforge.net,
user-mode-linux-user@...ts.sourceforge.net,
linux-api@...r.kernel.org,
Meredydd Luff <meredydd@...atehouse.org>,
David Drysdale <drysdale@...gle.com>
Subject: [PATCH v2 3/4] um: Add full asm/syscall.h support
Add subarchitecture-independent implementation of asm-generic/syscall.h
allowing access to user system call parameters and results:
* syscall_get_nr()
* syscall_rollback()
* syscall_get_error()
* syscall_get_return_value()
* syscall_set_return_value()
* syscall_get_arguments()
* syscall_set_arguments()
* syscall_get_arch() provided by arch/x86/um/asm/syscall.h
This provides the necessary syscall helpers needed by
HAVE_ARCH_SECCOMP_FILTER plus syscall_get_error().
This is inspired from Meredydd Luff's patch
(https://gerrit.chromium.org/gerrit/21425).
Signed-off-by: Mickaël Salaün <mic@...ikod.net>
Cc: Jeff Dike <jdike@...toit.com>
Cc: Richard Weinberger <richard@....at>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: Ingo Molnar <mingo@...hat.com>
Cc: H. Peter Anvin <hpa@...or.com>
Cc: Kees Cook <keescook@...omium.org>
Cc: Andy Lutomirski <luto@...capital.net>
Cc: Will Drewry <wad@...omium.org>
Cc: Meredydd Luff <meredydd@...atehouse.org>
Cc: David Drysdale <drysdale@...gle.com>
---
arch/um/include/asm/syscall-generic.h | 138 ++++++++++++++++++++++++++++++++++
arch/x86/um/asm/syscall.h | 1 +
2 files changed, 139 insertions(+)
create mode 100644 arch/um/include/asm/syscall-generic.h
diff --git a/arch/um/include/asm/syscall-generic.h b/arch/um/include/asm/syscall-generic.h
new file mode 100644
index 0000000..9fb9cf8
--- /dev/null
+++ b/arch/um/include/asm/syscall-generic.h
@@ -0,0 +1,138 @@
+/*
+ * Access to user system call parameters and results
+ *
+ * See asm-generic/syscall.h for function descriptions.
+ *
+ * Copyright (C) 2015 Mickaël Salaün <mic@...ikod.net>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#ifndef __UM_SYSCALL_GENERIC_H
+#define __UM_SYSCALL_GENERIC_H
+
+#include <asm/ptrace.h>
+#include <linux/err.h>
+#include <linux/sched.h>
+#include <sysdep/ptrace.h>
+
+static inline int syscall_get_nr(struct task_struct *task, struct pt_regs *regs)
+{
+
+ return PT_REGS_SYSCALL_NR(regs);
+}
+
+static inline void syscall_rollback(struct task_struct *task,
+ struct pt_regs *regs)
+{
+ /* do nothing */
+}
+
+static inline long syscall_get_error(struct task_struct *task,
+ struct pt_regs *regs)
+{
+ const long error = regs_return_value(regs);
+
+ return IS_ERR_VALUE(error) ? error : 0;
+}
+
+static inline long syscall_get_return_value(struct task_struct *task,
+ struct pt_regs *regs)
+{
+ return regs_return_value(regs);
+}
+
+static inline void syscall_set_return_value(struct task_struct *task,
+ struct pt_regs *regs,
+ int error, long val)
+{
+ PT_REGS_SET_SYSCALL_RETURN(regs, (long) error ?: val);
+}
+
+static inline void syscall_get_arguments(struct task_struct *task,
+ struct pt_regs *regs,
+ unsigned int i, unsigned int n,
+ unsigned long *args)
+{
+ const struct uml_pt_regs *r = ®s->regs;
+
+ switch (i) {
+ case 0:
+ if (!n--)
+ break;
+ *args++ = UPT_SYSCALL_ARG1(r);
+ case 1:
+ if (!n--)
+ break;
+ *args++ = UPT_SYSCALL_ARG2(r);
+ case 2:
+ if (!n--)
+ break;
+ *args++ = UPT_SYSCALL_ARG3(r);
+ case 3:
+ if (!n--)
+ break;
+ *args++ = UPT_SYSCALL_ARG4(r);
+ case 4:
+ if (!n--)
+ break;
+ *args++ = UPT_SYSCALL_ARG5(r);
+ case 5:
+ if (!n--)
+ break;
+ *args++ = UPT_SYSCALL_ARG6(r);
+ case 6:
+ if (!n--)
+ break;
+ default:
+ BUG();
+ break;
+ }
+}
+
+static inline void syscall_set_arguments(struct task_struct *task,
+ struct pt_regs *regs,
+ unsigned int i, unsigned int n,
+ const unsigned long *args)
+{
+ struct uml_pt_regs *r = ®s->regs;
+
+ switch (i) {
+ case 0:
+ if (!n--)
+ break;
+ UPT_SYSCALL_ARG1(r) = *args++;
+ case 1:
+ if (!n--)
+ break;
+ UPT_SYSCALL_ARG2(r) = *args++;
+ case 2:
+ if (!n--)
+ break;
+ UPT_SYSCALL_ARG3(r) = *args++;
+ case 3:
+ if (!n--)
+ break;
+ UPT_SYSCALL_ARG4(r) = *args++;
+ case 4:
+ if (!n--)
+ break;
+ UPT_SYSCALL_ARG5(r) = *args++;
+ case 5:
+ if (!n--)
+ break;
+ UPT_SYSCALL_ARG6(r) = *args++;
+ case 6:
+ if (!n--)
+ break;
+ default:
+ BUG();
+ break;
+ }
+}
+
+/* See arch/x86/um/asm/syscall.h for syscall_get_arch() definition. */
+
+#endif /* __UM_SYSCALL_GENERIC_H */
diff --git a/arch/x86/um/asm/syscall.h b/arch/x86/um/asm/syscall.h
index 81d6562..11ab90d 100644
--- a/arch/x86/um/asm/syscall.h
+++ b/arch/x86/um/asm/syscall.h
@@ -1,6 +1,7 @@
#ifndef __UM_ASM_SYSCALL_H
#define __UM_ASM_SYSCALL_H
+#include <asm/syscall-generic.h>
#include <uapi/linux/audit.h>
typedef asmlinkage long (*sys_call_ptr_t)(unsigned long, unsigned long,
--
2.6.4
--
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