forked from Minki/linux
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>
This commit is contained in:
Dominik Brodowski
Ingo Molnar
parent
fa697140f9
commit
7303e30ec1
@ -24,6 +24,17 @@
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#include <asm/siginfo.h>
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#include <asm/signal.h>
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#ifdef CONFIG_ARCH_HAS_SYSCALL_WRAPPER
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/*
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* It may be useful for an architecture to override the definitions of the
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* COMPAT_SYSCALL_DEFINE0 and COMPAT_SYSCALL_DEFINEx() macros, in particular
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* to use a different calling convention for syscalls. To allow for that,
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+ the prototypes for the compat_sys_*() functions below will *not* be included
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* if CONFIG_ARCH_HAS_SYSCALL_WRAPPER is enabled.
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*/
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#include <asm/syscall_wrapper.h>
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#endif /* CONFIG_ARCH_HAS_SYSCALL_WRAPPER */
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#ifndef COMPAT_USE_64BIT_TIME
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#define COMPAT_USE_64BIT_TIME 0
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#endif
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@ -32,10 +43,12 @@
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#define __SC_DELOUSE(t,v) ((__force t)(unsigned long)(v))
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#endif
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#ifndef COMPAT_SYSCALL_DEFINE0
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#define COMPAT_SYSCALL_DEFINE0(name) \
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asmlinkage long compat_sys_##name(void); \
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ALLOW_ERROR_INJECTION(compat_sys_##name, ERRNO); \
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asmlinkage long compat_sys_##name(void)
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#endif /* COMPAT_SYSCALL_DEFINE0 */
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#define COMPAT_SYSCALL_DEFINE1(name, ...) \
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COMPAT_SYSCALL_DEFINEx(1, _##name, __VA_ARGS__)
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@ -50,6 +63,7 @@
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#define COMPAT_SYSCALL_DEFINE6(name, ...) \
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COMPAT_SYSCALL_DEFINEx(6, _##name, __VA_ARGS__)
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#ifndef COMPAT_SYSCALL_DEFINEx
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#define COMPAT_SYSCALL_DEFINEx(x, name, ...) \
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asmlinkage long compat_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__));\
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asmlinkage long compat_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__))\
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@ -62,6 +76,7 @@
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return C_SYSC##name(__MAP(x,__SC_DELOUSE,__VA_ARGS__)); \
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} \
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static inline long C_SYSC##name(__MAP(x,__SC_DECL,__VA_ARGS__))
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#endif /* COMPAT_SYSCALL_DEFINEx */
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#ifndef compat_user_stack_pointer
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#define compat_user_stack_pointer() current_user_stack_pointer()
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@ -517,7 +532,12 @@ int __compat_save_altstack(compat_stack_t __user *, unsigned long);
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* Please note that these prototypes here are only provided for information
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* purposes, for static analysis, and for linking from the syscall table.
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* These functions should not be called elsewhere from kernel code.
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*
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* As the syscall calling convention may be different from the default
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* for architectures overriding the syscall calling convention, do not
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* include the prototypes if CONFIG_ARCH_HAS_SYSCALL_WRAPPER is enabled.
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*/
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#ifndef CONFIG_ARCH_HAS_SYSCALL_WRAPPER
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asmlinkage long compat_sys_io_setup(unsigned nr_reqs, u32 __user *ctx32p);
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asmlinkage long compat_sys_io_submit(compat_aio_context_t ctx_id, int nr,
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u32 __user *iocb);
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@ -955,6 +975,8 @@ asmlinkage long compat_sys_stime(compat_time_t __user *tptr);
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/* obsolete: net/socket.c */
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asmlinkage long compat_sys_socketcall(int call, u32 __user *args);
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#endif /* CONFIG_ARCH_HAS_SYSCALL_WRAPPER */
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/*
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* For most but not all architectures, "am I in a compat syscall?" and
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@ -1925,8 +1925,11 @@ config ARCH_HAS_SYNC_CORE_BEFORE_USERMODE
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bool
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# It may be useful for an architecture to override the definitions of the
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# SYSCALL_DEFINE() and __SYSCALL_DEFINEx() macros in <linux/syscalls.h>,
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# in particular to use a different calling convention for syscalls.
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# SYSCALL_DEFINE() and __SYSCALL_DEFINEx() macros in <linux/syscalls.h>
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# and the COMPAT_ variants in <linux/compat.h>, in particular to use a
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# different calling convention for syscalls. They can also override the
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# macros for not-implemented syscalls in kernel/sys_ni.c and
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# kernel/time/posix-stubs.c. All these overrides need to be available in
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# <asm/syscall_wrapper.h>.
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config ARCH_HAS_SYSCALL_WRAPPER
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def_bool n
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depends on !COMPAT
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@ -5,6 +5,11 @@
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#include <asm/unistd.h>
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#ifdef CONFIG_ARCH_HAS_SYSCALL_WRAPPER
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/* Architectures may override COND_SYSCALL and COND_SYSCALL_COMPAT */
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#include <asm/syscall_wrapper.h>
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#endif /* CONFIG_ARCH_HAS_SYSCALL_WRAPPER */
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/* we can't #include <linux/syscalls.h> here,
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but tell gcc to not warn with -Wmissing-prototypes */
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asmlinkage long sys_ni_syscall(void);
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@ -17,8 +22,13 @@ asmlinkage long sys_ni_syscall(void)
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return -ENOSYS;
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}
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#ifndef COND_SYSCALL
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#define COND_SYSCALL(name) cond_syscall(sys_##name)
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#endif /* COND_SYSCALL */
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#ifndef COND_SYSCALL_COMPAT
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#define COND_SYSCALL_COMPAT(name) cond_syscall(compat_sys_##name)
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#endif /* COND_SYSCALL_COMPAT */
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/*
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* This list is kept in the same order as include/uapi/asm-generic/unistd.h.
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@ -19,6 +19,11 @@
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#include <linux/posix-timers.h>
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#include <linux/compat.h>
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#ifdef CONFIG_ARCH_HAS_SYSCALL_WRAPPER
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/* Architectures may override SYS_NI and COMPAT_SYS_NI */
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#include <asm/syscall_wrapper.h>
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#endif
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asmlinkage long sys_ni_posix_timers(void)
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{
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pr_err_once("process %d (%s) attempted a POSIX timer syscall "
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@ -27,8 +32,13 @@ asmlinkage long sys_ni_posix_timers(void)
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return -ENOSYS;
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}
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#ifndef SYS_NI
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#define SYS_NI(name) SYSCALL_ALIAS(sys_##name, sys_ni_posix_timers)
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#endif
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#ifndef COMPAT_SYS_NI
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#define COMPAT_SYS_NI(name) SYSCALL_ALIAS(compat_sys_##name, sys_ni_posix_timers)
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#endif
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SYS_NI(timer_create);
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SYS_NI(timer_gettime);
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