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authorDominik Brodowski <linux@dominikbrodowski.net>2018-04-05 11:53:03 +0200
committerIngo Molnar <mingo@kernel.org>2018-04-05 16:59:38 +0200
commit7303e30ec1d8fb5ca1f07c92d069241c32b2ee1b (patch)
tree9bf0343c73e0f5562bd8972c25bf8ffa280e8845 /kernel
parentfa697140f9a20119a9ec8fd7460cc4314fbdaff3 (diff)
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syscalls/core: Prepare CONFIG_ARCH_HAS_SYSCALL_WRAPPER=y for compat syscalls
It may be useful for an architecture to override the definitions of the COMPAT_SYSCALL_DEFINE0() and __COMPAT_SYSCALL_DEFINEx() macros in <linux/compat.h>, in particular to use a different calling convention for syscalls. This patch provides a mechanism to do so, based on the previously introduced CONFIG_ARCH_HAS_SYSCALL_WRAPPER. If it is enabled, <asm/sycall_wrapper.h> is included in <linux/compat.h> and may be used to define the macros mentioned above. Moreover, as the syscall calling convention may be different if CONFIG_ARCH_HAS_SYSCALL_WRAPPER is set, the compat syscall function prototypes in <linux/compat.h> are #ifndef'd out in that case. As some of the syscalls and/or compat syscalls may not be present, the COND_SYSCALL() and COND_SYSCALL_COMPAT() macros in kernel/sys_ni.c as well as the SYS_NI() and COMPAT_SYS_NI() macros in kernel/time/posix-stubs.c can be re-defined in <asm/syscall_wrapper.h> iff CONFIG_ARCH_HAS_SYSCALL_WRAPPER is enabled. Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20180405095307.3730-5-linux@dominikbrodowski.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/sys_ni.c10
-rw-r--r--kernel/time/posix-stubs.c10
2 files changed, 20 insertions, 0 deletions
diff --git a/kernel/sys_ni.c b/kernel/sys_ni.c
index 6cafc008f6db..9791364925dc 100644
--- a/kernel/sys_ni.c
+++ b/kernel/sys_ni.c
@@ -5,6 +5,11 @@
#include <asm/unistd.h>
+#ifdef CONFIG_ARCH_HAS_SYSCALL_WRAPPER
+/* Architectures may override COND_SYSCALL and COND_SYSCALL_COMPAT */
+#include <asm/syscall_wrapper.h>
+#endif /* CONFIG_ARCH_HAS_SYSCALL_WRAPPER */
+
/* we can't #include <linux/syscalls.h> here,
but tell gcc to not warn with -Wmissing-prototypes */
asmlinkage long sys_ni_syscall(void);
@@ -17,8 +22,13 @@ asmlinkage long sys_ni_syscall(void)
return -ENOSYS;
}
+#ifndef COND_SYSCALL
#define COND_SYSCALL(name) cond_syscall(sys_##name)
+#endif /* COND_SYSCALL */
+
+#ifndef COND_SYSCALL_COMPAT
#define COND_SYSCALL_COMPAT(name) cond_syscall(compat_sys_##name)
+#endif /* COND_SYSCALL_COMPAT */
/*
* This list is kept in the same order as include/uapi/asm-generic/unistd.h.
diff --git a/kernel/time/posix-stubs.c b/kernel/time/posix-stubs.c
index b258bee13b02..69a937c3cd81 100644
--- a/kernel/time/posix-stubs.c
+++ b/kernel/time/posix-stubs.c
@@ -19,6 +19,11 @@
#include <linux/posix-timers.h>
#include <linux/compat.h>
+#ifdef CONFIG_ARCH_HAS_SYSCALL_WRAPPER
+/* Architectures may override SYS_NI and COMPAT_SYS_NI */
+#include <asm/syscall_wrapper.h>
+#endif
+
asmlinkage long sys_ni_posix_timers(void)
{
pr_err_once("process %d (%s) attempted a POSIX timer syscall "
@@ -27,8 +32,13 @@ asmlinkage long sys_ni_posix_timers(void)
return -ENOSYS;
}
+#ifndef SYS_NI
#define SYS_NI(name) SYSCALL_ALIAS(sys_##name, sys_ni_posix_timers)
+#endif
+
+#ifndef COMPAT_SYS_NI
#define COMPAT_SYS_NI(name) SYSCALL_ALIAS(compat_sys_##name, sys_ni_posix_timers)
+#endif
SYS_NI(timer_create);
SYS_NI(timer_gettime);