syscalls/core, syscalls/x86: Rename struct pt_regs-based sys_*() to __x64_sys_*()
This rename allows us to have a coherent syscall stub naming convention on
64-bit x86 (0xffffffff prefix removed):
810f0af0 t kernel_waitid # common (32/64) kernel helper
<inline> __do_sys_waitid # inlined helper doing actual work
810f0be0 t __se_sys_waitid # C func calling inlined helper
<inline> __do_compat_sys_waitid # inlined helper doing actual work
810f0d80 t __se_compat_sys_waitid # compat C func calling inlined helper
810f2080 T __x64_sys_waitid # x64 64-bit-ptregs -> C stub
810f20b0 T __ia32_sys_waitid # ia32 32-bit-ptregs -> C stub[*]
810f2470 T __ia32_compat_sys_waitid # ia32 32-bit-ptregs -> compat C stub
810f2490 T __x32_compat_sys_waitid # x32 64-bit-ptregs -> compat C stub
[*] This stub is unused, as the syscall table links
__ia32_compat_sys_waitid instead of __ia32_sys_waitid as we need
a compat variant here.
Suggested-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
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: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20180409105145.5364-4-linux@dominikbrodowski.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Dominik Brodowski
committed by
Ingo Molnar
Ingo Molnar
parent
5ac9efa3c5
commit
d5a00528b5
@@ -44,12 +44,23 @@
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return __se_sys##name(SC_IA32_REGS_TO_ARGS(x,__VA_ARGS__));\
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}
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/*
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* To keep the naming coherent, re-define SYSCALL_DEFINE0 to create an alias
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* named __ia32_sys_*()
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*/
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#define SYSCALL_DEFINE0(sname) \
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SYSCALL_METADATA(_##sname, 0); \
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asmlinkage long __x64_sys_##sname(void); \
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ALLOW_ERROR_INJECTION(__x64_sys_##sname, ERRNO); \
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SYSCALL_ALIAS(__ia32_sys_##sname, __x64_sys_##sname); \
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asmlinkage long __x64_sys_##sname(void)
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#define COND_SYSCALL(name) \
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cond_syscall(sys_##name); \
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cond_syscall(__x64_sys_##name); \
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cond_syscall(__ia32_sys_##name)
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#define SYS_NI(name) \
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SYSCALL_ALIAS(sys_##name, sys_ni_posix_timers); \
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SYSCALL_ALIAS(__x64_sys_##name, sys_ni_posix_timers); \
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SYSCALL_ALIAS(__ia32_sys_##name, sys_ni_posix_timers)
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#else /* CONFIG_IA32_EMULATION */
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@@ -81,8 +92,7 @@
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/*
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* Compat means IA32_EMULATION and/or X86_X32. As they use a different
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* mapping of registers to parameters, we need to generate stubs for each
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* of them. There is no need to implement COMPAT_SYSCALL_DEFINE0, as it is
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* unused on x86.
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* of them.
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*/
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#define COMPAT_SYSCALL_DEFINEx(x, name, ...) \
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static long __se_compat_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__)); \
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@@ -114,13 +124,13 @@
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/*
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* Instead of the generic __SYSCALL_DEFINEx() definition, this macro takes
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* struct pt_regs *regs as the only argument of the syscall stub named
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* sys_*(). It decodes just the registers it needs and passes them on to
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* __x64_sys_*(). It decodes just the registers it needs and passes them on to
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* the __se_sys_*() wrapper performing sign extension and then to the
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* __do_sys_*() function doing the actual job. These wrappers and functions
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* are inlined (at least in very most cases), meaning that the assembly looks
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* as follows (slightly re-ordered for better readability):
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*
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* <sys_recv>: <-- syscall with 4 parameters
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* <__x64_sys_recv>: <-- syscall with 4 parameters
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* callq <__fentry__>
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*
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* mov 0x70(%rdi),%rdi <-- decode regs->di
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@@ -143,18 +153,13 @@
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* If IA32_EMULATION is enabled, this macro generates an additional wrapper
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* named __ia32_sys_*() which decodes the struct pt_regs *regs according
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* to the i386 calling convention (bx, cx, dx, si, di, bp).
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*
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* As the generic SYSCALL_DEFINE0() macro does not decode any parameters for
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* obvious reasons, and passing struct pt_regs *regs to it in %rdi does not
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* hurt, there is no need to override it, or to define it differently for
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* IA32_EMULATION.
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*/
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#define __SYSCALL_DEFINEx(x, name, ...) \
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asmlinkage long sys##name(const struct pt_regs *regs); \
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ALLOW_ERROR_INJECTION(sys##name, ERRNO); \
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asmlinkage long __x64_sys##name(const struct pt_regs *regs); \
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ALLOW_ERROR_INJECTION(__x64_sys##name, ERRNO); \
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static long __se_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__)); \
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static inline long __do_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__));\
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asmlinkage long sys##name(const struct pt_regs *regs) \
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asmlinkage long __x64_sys##name(const struct pt_regs *regs) \
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{ \
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return __se_sys##name(SC_X86_64_REGS_TO_ARGS(x,__VA_ARGS__));\
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} \
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@@ -168,13 +173,37 @@
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} \
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static inline long __do_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__))
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/*
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* As the generic SYSCALL_DEFINE0() macro does not decode any parameters for
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* obvious reasons, and passing struct pt_regs *regs to it in %rdi does not
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* hurt, we only need to re-define it here to keep the naming congruent to
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* SYSCALL_DEFINEx() -- which is essential for the COND_SYSCALL() and SYS_NI()
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* macros to work correctly.
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*/
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#ifndef SYSCALL_DEFINE0
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#define SYSCALL_DEFINE0(sname) \
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SYSCALL_METADATA(_##sname, 0); \
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asmlinkage long __x64_sys_##sname(void); \
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ALLOW_ERROR_INJECTION(__x64_sys_##sname, ERRNO); \
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asmlinkage long __x64_sys_##sname(void)
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#endif
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#ifndef COND_SYSCALL
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#define COND_SYSCALL(name) cond_syscall(__x64_sys_##name)
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#endif
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#ifndef SYS_NI
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#define SYS_NI(name) SYSCALL_ALIAS(__x64_sys_##name, sys_ni_posix_timers);
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#endif
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/*
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* For VSYSCALLS, we need to declare these three syscalls with the new
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* pt_regs-based calling convention for in-kernel use.
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*/
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struct pt_regs;
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asmlinkage long sys_getcpu(const struct pt_regs *regs); /* di,si,dx */
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asmlinkage long sys_gettimeofday(const struct pt_regs *regs); /* di,si */
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asmlinkage long sys_time(const struct pt_regs *regs); /* di */
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asmlinkage long __x64_sys_getcpu(const struct pt_regs *regs);
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asmlinkage long __x64_sys_gettimeofday(const struct pt_regs *regs);
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asmlinkage long __x64_sys_time(const struct pt_regs *regs);
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#endif /* _ASM_X86_SYSCALL_WRAPPER_H */
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