Merge tag 'x86-entry-2020-03-30' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 entry code updates from Thomas Gleixner:

 - Convert the 32bit syscalls to be pt_regs based which removes the
   requirement to push all 6 potential arguments onto the stack and
   consolidates the interface with the 64bit variant

 - The first small portion of the exception and syscall related entry
   code consolidation which aims to address the recently discovered
   issues vs. RCU, int3, NMI and some other exceptions which can
   interrupt any context. The bulk of the changes is still work in
   progress and aimed for 5.8.

 - A few lockdep namespace cleanups which have been applied into this
   branch to keep the prerequisites for the ongoing work confined.

* tag 'x86-entry-2020-03-30' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (35 commits)
  x86/entry: Fix build error x86 with !CONFIG_POSIX_TIMERS
  lockdep: Rename trace_{hard,soft}{irq_context,irqs_enabled}()
  lockdep: Rename trace_softirqs_{on,off}()
  lockdep: Rename trace_hardirq_{enter,exit}()
  x86/entry: Rename ___preempt_schedule
  x86: Remove unneeded includes
  x86/entry: Drop asmlinkage from syscalls
  x86/entry/32: Enable pt_regs based syscalls
  x86/entry/32: Use IA32-specific wrappers for syscalls taking 64-bit arguments
  x86/entry/32: Rename 32-bit specific syscalls
  x86/entry/32: Clean up syscall_32.tbl
  x86/entry: Remove ABI prefixes from functions in syscall tables
  x86/entry/64: Add __SYSCALL_COMMON()
  x86/entry: Remove syscall qualifier support
  x86/entry/64: Remove ptregs qualifier from syscall table
  x86/entry: Move max syscall number calculation to syscallhdr.sh
  x86/entry/64: Split X32 syscall table into its own file
  x86/entry/64: Move sys_ni_syscall stub to common.c
  x86/entry/64: Use syscall wrappers for x32_rt_sigreturn
  x86/entry: Refactor SYS_NI macros
  ...

1 files changed, 155 insertions, 132 deletions

diff --git a/arch/x86/include/asm/syscall_wrapper.h b/arch/x86/include/asm/syscall_wrapper.h
index e2389ce9bf58..a84333adeef2 100644
--- a/arch/x86/include/asm/syscall_wrapper.h
+++ b/arch/x86/include/asm/syscall_wrapper.h
@@ -8,6 +8,50 @@
 
 struct pt_regs;
 
+extern long __x64_sys_ni_syscall(const struct pt_regs *regs);
+extern long __ia32_sys_ni_syscall(const struct pt_regs *regs);
+
+/*
+ * Instead of the generic __SYSCALL_DEFINEx() definition, the x86 version takes
+ * struct pt_regs *regs as the only argument of the syscall stub(s) named as:
+ * __x64_sys_*()         - 64-bit native syscall
+ * __ia32_sys_*()        - 32-bit native syscall or common compat syscall
+ * __ia32_compat_sys_*() - 32-bit compat syscall
+ * __x32_compat_sys_*()  - 64-bit X32 compat syscall
+ *
+ * The registers are decoded according to the ABI:
+ * 64-bit: RDI, RSI, RDX, R10, R8, R9
+ * 32-bit: EBX, ECX, EDX, ESI, EDI, EBP
+ *
+ * The stub then passes the decoded arguments to the __se_sys_*() wrapper to
+ * perform sign-extension (omitted for zero-argument syscalls).  Finally the
+ * arguments are passed to the __do_sys_*() function which is the actual
+ * syscall.  These wrappers are marked as inline so the compiler can optimize
+ * the functions where appropriate.
+ *
+ * Example assembly (slightly re-ordered for better readability):
+ *
+ * <__x64_sys_recv>:		<-- syscall with 4 parameters
+ *	callq	<__fentry__>
+ *
+ *	mov	0x70(%rdi),%rdi	<-- decode regs->di
+ *	mov	0x68(%rdi),%rsi	<-- decode regs->si
+ *	mov	0x60(%rdi),%rdx	<-- decode regs->dx
+ *	mov	0x38(%rdi),%rcx	<-- decode regs->r10
+ *
+ *	xor	%r9d,%r9d	<-- clear %r9
+ *	xor	%r8d,%r8d	<-- clear %r8
+ *
+ *	callq	__sys_recvfrom	<-- do the actual work in __sys_recvfrom()
+ *				    which takes 6 arguments
+ *
+ *	cltq			<-- extend return value to 64-bit
+ *	retq			<-- return
+ *
+ * This approach avoids leaking random user-provided register content down
+ * the call chain.
+ */
+
 /* Mapping of registers to parameters for syscalls on x86-64 and x32 */
 #define SC_X86_64_REGS_TO_ARGS(x, ...)					\
 	__MAP(x,__SC_ARGS						\
@@ -21,68 +65,96 @@ struct pt_regs;
 	      ,,(unsigned int)regs->dx,,(unsigned int)regs->si		\
 	      ,,(unsigned int)regs->di,,(unsigned int)regs->bp)
 
-#ifdef CONFIG_IA32_EMULATION
-/*
- * For IA32 emulation, we need to handle "compat" syscalls *and* create
- * additional wrappers (aptly named __ia32_sys_xyzzy) which decode the
- * ia32 regs in the proper order for shared or "common" syscalls. As some
- * syscalls may not be implemented, we need to expand COND_SYSCALL in
- * kernel/sys_ni.c and SYS_NI in kernel/time/posix-stubs.c to cover this
- * case as well.
- */
-#define __IA32_COMPAT_SYS_STUB0(x, name)				\
-	asmlinkage long __ia32_compat_sys_##name(const struct pt_regs *regs);\
-	ALLOW_ERROR_INJECTION(__ia32_compat_sys_##name, ERRNO);		\
-	asmlinkage long __ia32_compat_sys_##name(const struct pt_regs *regs)\
+#define __SYS_STUB0(abi, name)						\
+	long __##abi##_##name(const struct pt_regs *regs);		\
+	ALLOW_ERROR_INJECTION(__##abi##_##name, ERRNO);			\
+	long __##abi##_##name(const struct pt_regs *regs)		\
+		__alias(__do_##name);
+
+#define __SYS_STUBx(abi, name, ...)					\
+	long __##abi##_##name(const struct pt_regs *regs);		\
+	ALLOW_ERROR_INJECTION(__##abi##_##name, ERRNO);			\
+	long __##abi##_##name(const struct pt_regs *regs)		\
 	{								\
-		return __se_compat_sys_##name();			\
+		return __se_##name(__VA_ARGS__);			\
 	}
 
-#define __IA32_COMPAT_SYS_STUBx(x, name, ...)				\
-	asmlinkage long __ia32_compat_sys##name(const struct pt_regs *regs);\
-	ALLOW_ERROR_INJECTION(__ia32_compat_sys##name, ERRNO);		\
-	asmlinkage long __ia32_compat_sys##name(const struct pt_regs *regs)\
+#define __COND_SYSCALL(abi, name)					\
+	__weak long __##abi##_##name(const struct pt_regs *__unused)	\
 	{								\
-		return __se_compat_sys##name(SC_IA32_REGS_TO_ARGS(x,__VA_ARGS__));\
+		return sys_ni_syscall();				\
 	}
 
+#define __SYS_NI(abi, name)						\
+	SYSCALL_ALIAS(__##abi##_##name, sys_ni_posix_timers);
+
+#ifdef CONFIG_X86_64
+#define __X64_SYS_STUB0(name)						\
+	__SYS_STUB0(x64, sys_##name)
+
+#define __X64_SYS_STUBx(x, name, ...)					\
+	__SYS_STUBx(x64, sys##name,					\
+		    SC_X86_64_REGS_TO_ARGS(x, __VA_ARGS__))
+
+#define __X64_COND_SYSCALL(name)					\
+	__COND_SYSCALL(x64, sys_##name)
+
+#define __X64_SYS_NI(name)						\
+	__SYS_NI(x64, sys_##name)
+#else /* CONFIG_X86_64 */
+#define __X64_SYS_STUB0(name)
+#define __X64_SYS_STUBx(x, name, ...)
+#define __X64_COND_SYSCALL(name)
+#define __X64_SYS_NI(name)
+#endif /* CONFIG_X86_64 */
+
+#if defined(CONFIG_X86_32) || defined(CONFIG_IA32_EMULATION)
+#define __IA32_SYS_STUB0(name)						\
+	__SYS_STUB0(ia32, sys_##name)
+
 #define __IA32_SYS_STUBx(x, name, ...)					\
-	asmlinkage long __ia32_sys##name(const struct pt_regs *regs);	\
-	ALLOW_ERROR_INJECTION(__ia32_sys##name, ERRNO);			\
-	asmlinkage long __ia32_sys##name(const struct pt_regs *regs)	\
-	{								\
-		return __se_sys##name(SC_IA32_REGS_TO_ARGS(x,__VA_ARGS__));\
-	}
+	__SYS_STUBx(ia32, sys##name,					\
+		    SC_IA32_REGS_TO_ARGS(x, __VA_ARGS__))
+
+#define __IA32_COND_SYSCALL(name)					\
+	__COND_SYSCALL(ia32, sys_##name)
 
+#define __IA32_SYS_NI(name)						\
+	__SYS_NI(ia32, sys_##name)
+#else /* CONFIG_X86_32 || CONFIG_IA32_EMULATION */
+#define __IA32_SYS_STUB0(name)
+#define __IA32_SYS_STUBx(x, name, ...)
+#define __IA32_COND_SYSCALL(name)
+#define __IA32_SYS_NI(name)
+#endif /* CONFIG_X86_32 || CONFIG_IA32_EMULATION */
+
+#ifdef CONFIG_IA32_EMULATION
 /*
- * To keep the naming coherent, re-define SYSCALL_DEFINE0 to create an alias
- * named __ia32_sys_*()
+ * For IA32 emulation, we need to handle "compat" syscalls *and* create
+ * additional wrappers (aptly named __ia32_sys_xyzzy) which decode the
+ * ia32 regs in the proper order for shared or "common" syscalls. As some
+ * syscalls may not be implemented, we need to expand COND_SYSCALL in
+ * kernel/sys_ni.c and SYS_NI in kernel/time/posix-stubs.c to cover this
+ * case as well.
  */
+#define __IA32_COMPAT_SYS_STUB0(name)					\
+	__SYS_STUB0(ia32, compat_sys_##name)
 
-#define SYSCALL_DEFINE0(sname)						\
-	SYSCALL_METADATA(_##sname, 0);					\
-	asmlinkage long __x64_sys_##sname(const struct pt_regs *__unused);\
-	ALLOW_ERROR_INJECTION(__x64_sys_##sname, ERRNO);		\
-	SYSCALL_ALIAS(__ia32_sys_##sname, __x64_sys_##sname);		\
-	asmlinkage long __x64_sys_##sname(const struct pt_regs *__unused)
+#define __IA32_COMPAT_SYS_STUBx(x, name, ...)				\
+	__SYS_STUBx(ia32, compat_sys##name,				\
+		    SC_IA32_REGS_TO_ARGS(x, __VA_ARGS__))
 
-#define COND_SYSCALL(name)							\
-	asmlinkage __weak long __x64_sys_##name(const struct pt_regs *__unused)	\
-	{									\
-		return sys_ni_syscall();					\
-	}									\
-	asmlinkage __weak long __ia32_sys_##name(const struct pt_regs *__unused)\
-	{									\
-		return sys_ni_syscall();					\
-	}
+#define __IA32_COMPAT_COND_SYSCALL(name)				\
+	__COND_SYSCALL(ia32, compat_sys_##name)
 
-#define SYS_NI(name)							\
-	SYSCALL_ALIAS(__x64_sys_##name, sys_ni_posix_timers);		\
-	SYSCALL_ALIAS(__ia32_sys_##name, sys_ni_posix_timers)
+#define __IA32_COMPAT_SYS_NI(name)					\
+	__SYS_NI(ia32, compat_sys_##name)
 
 #else /* CONFIG_IA32_EMULATION */
+#define __IA32_COMPAT_SYS_STUB0(name)
 #define __IA32_COMPAT_SYS_STUBx(x, name, ...)
-#define __IA32_SYS_STUBx(x, fullname, name, ...)
+#define __IA32_COMPAT_COND_SYSCALL(name)
+#define __IA32_COMPAT_SYS_NI(name)
 #endif /* CONFIG_IA32_EMULATION */
 
 
@@ -92,25 +164,23 @@ struct pt_regs;
  * of the x86-64-style parameter ordering of x32 syscalls. The syscalls common
  * with x86_64 obviously do not need such care.
  */
-#define __X32_COMPAT_SYS_STUB0(x, name, ...)				\
-	asmlinkage long __x32_compat_sys_##name(const struct pt_regs *regs);\
-	ALLOW_ERROR_INJECTION(__x32_compat_sys_##name, ERRNO);		\
-	asmlinkage long __x32_compat_sys_##name(const struct pt_regs *regs)\
-	{								\
-		return __se_compat_sys_##name();\
-	}
+#define __X32_COMPAT_SYS_STUB0(name)					\
+	__SYS_STUB0(x32, compat_sys_##name)
 
 #define __X32_COMPAT_SYS_STUBx(x, name, ...)				\
-	asmlinkage long __x32_compat_sys##name(const struct pt_regs *regs);\
-	ALLOW_ERROR_INJECTION(__x32_compat_sys##name, ERRNO);		\
-	asmlinkage long __x32_compat_sys##name(const struct pt_regs *regs)\
-	{								\
-		return __se_compat_sys##name(SC_X86_64_REGS_TO_ARGS(x,__VA_ARGS__));\
-	}
+	__SYS_STUBx(x32, compat_sys##name,				\
+		    SC_X86_64_REGS_TO_ARGS(x, __VA_ARGS__))
+
+#define __X32_COMPAT_COND_SYSCALL(name)					\
+	__COND_SYSCALL(x32, compat_sys_##name)
 
+#define __X32_COMPAT_SYS_NI(name)					\
+	__SYS_NI(x32, compat_sys_##name)
 #else /* CONFIG_X86_X32 */
-#define __X32_COMPAT_SYS_STUB0(x, name)
+#define __X32_COMPAT_SYS_STUB0(name)
 #define __X32_COMPAT_SYS_STUBx(x, name, ...)
+#define __X32_COMPAT_COND_SYSCALL(name)
+#define __X32_COMPAT_SYS_NI(name)
 #endif /* CONFIG_X86_X32 */
 
 
@@ -121,15 +191,12 @@ struct pt_regs;
  * of them.
  */
 #define COMPAT_SYSCALL_DEFINE0(name)					\
-	static long __se_compat_sys_##name(void);			\
-	static inline long __do_compat_sys_##name(void);		\
-	__IA32_COMPAT_SYS_STUB0(x, name)				\
-	__X32_COMPAT_SYS_STUB0(x, name)					\
-	static long __se_compat_sys_##name(void)			\
-	{								\
-		return __do_compat_sys_##name();			\
-	}								\
-	static inline long __do_compat_sys_##name(void)
+	static long							\
+	__do_compat_sys_##name(const struct pt_regs *__unused);		\
+	__IA32_COMPAT_SYS_STUB0(name)					\
+	__X32_COMPAT_SYS_STUB0(name)					\
+	static long							\
+	__do_compat_sys_##name(const struct pt_regs *__unused)
 
 #define COMPAT_SYSCALL_DEFINEx(x, name, ...)					\
 	static long __se_compat_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__));	\
@@ -148,58 +215,19 @@ struct pt_regs;
  * kernel/time/posix-stubs.c to cover this case as well.
  */
 #define COND_SYSCALL_COMPAT(name) 					\
-	cond_syscall(__ia32_compat_sys_##name);				\
-	cond_syscall(__x32_compat_sys_##name)
+	__IA32_COMPAT_COND_SYSCALL(name)				\
+	__X32_COMPAT_COND_SYSCALL(name)
 
 #define COMPAT_SYS_NI(name)						\
-	SYSCALL_ALIAS(__ia32_compat_sys_##name, sys_ni_posix_timers);	\
-	SYSCALL_ALIAS(__x32_compat_sys_##name, sys_ni_posix_timers)
+	__IA32_COMPAT_SYS_NI(name)					\
+	__X32_COMPAT_SYS_NI(name)
 
 #endif /* CONFIG_COMPAT */
 
-
-/*
- * Instead of the generic __SYSCALL_DEFINEx() definition, this macro takes
- * struct pt_regs *regs as the only argument of the syscall stub named
- * __x64_sys_*(). It decodes just the registers it needs and passes them on to
- * the __se_sys_*() wrapper performing sign extension and then to the
- * __do_sys_*() function doing the actual job. These wrappers and functions
- * are inlined (at least in very most cases), meaning that the assembly looks
- * as follows (slightly re-ordered for better readability):
- *
- * <__x64_sys_recv>:		<-- syscall with 4 parameters
- *	callq	<__fentry__>
- *
- *	mov	0x70(%rdi),%rdi	<-- decode regs->di
- *	mov	0x68(%rdi),%rsi	<-- decode regs->si
- *	mov	0x60(%rdi),%rdx	<-- decode regs->dx
- *	mov	0x38(%rdi),%rcx	<-- decode regs->r10
- *
- *	xor	%r9d,%r9d	<-- clear %r9
- *	xor	%r8d,%r8d	<-- clear %r8
- *
- *	callq	__sys_recvfrom	<-- do the actual work in __sys_recvfrom()
- *				    which takes 6 arguments
- *
- *	cltq			<-- extend return value to 64-bit
- *	retq			<-- return
- *
- * This approach avoids leaking random user-provided register content down
- * the call chain.
- *
- * If IA32_EMULATION is enabled, this macro generates an additional wrapper
- * named __ia32_sys_*() which decodes the struct pt_regs *regs according
- * to the i386 calling convention (bx, cx, dx, si, di, bp).
- */
 #define __SYSCALL_DEFINEx(x, name, ...)					\
-	asmlinkage long __x64_sys##name(const struct pt_regs *regs);	\
-	ALLOW_ERROR_INJECTION(__x64_sys##name, ERRNO);			\
 	static long __se_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__));	\
 	static inline long __do_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__));\
-	asmlinkage long __x64_sys##name(const struct pt_regs *regs)	\
-	{								\
-		return __se_sys##name(SC_X86_64_REGS_TO_ARGS(x,__VA_ARGS__));\
-	}								\
+	__X64_SYS_STUBx(x, name, __VA_ARGS__)				\
 	__IA32_SYS_STUBx(x, name, __VA_ARGS__)				\
 	static long __se_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__))	\
 	{								\
@@ -217,33 +245,28 @@ struct pt_regs;
  * SYSCALL_DEFINEx() -- which is essential for the COND_SYSCALL() and SYS_NI()
  * macros to work correctly.
  */
-#ifndef SYSCALL_DEFINE0
 #define SYSCALL_DEFINE0(sname)						\
 	SYSCALL_METADATA(_##sname, 0);					\
-	asmlinkage long __x64_sys_##sname(const struct pt_regs *__unused);\
-	ALLOW_ERROR_INJECTION(__x64_sys_##sname, ERRNO);		\
-	asmlinkage long __x64_sys_##sname(const struct pt_regs *__unused)
-#endif
-
-#ifndef COND_SYSCALL
-#define COND_SYSCALL(name) 							\
-	asmlinkage __weak long __x64_sys_##name(const struct pt_regs *__unused)	\
-	{									\
-		return sys_ni_syscall();					\
-	}
-#endif
+	static long __do_sys_##sname(const struct pt_regs *__unused);	\
+	__X64_SYS_STUB0(sname)						\
+	__IA32_SYS_STUB0(sname)						\
+	static long __do_sys_##sname(const struct pt_regs *__unused)
+
+#define COND_SYSCALL(name)						\
+	__X64_COND_SYSCALL(name)					\
+	__IA32_COND_SYSCALL(name)
 
-#ifndef SYS_NI
-#define SYS_NI(name) SYSCALL_ALIAS(__x64_sys_##name, sys_ni_posix_timers);
-#endif
+#define SYS_NI(name)							\
+	__X64_SYS_NI(name)						\
+	__IA32_SYS_NI(name)
 
 
 /*
  * For VSYSCALLS, we need to declare these three syscalls with the new
  * pt_regs-based calling convention for in-kernel use.
  */
-asmlinkage long __x64_sys_getcpu(const struct pt_regs *regs);
-asmlinkage long __x64_sys_gettimeofday(const struct pt_regs *regs);
-asmlinkage long __x64_sys_time(const struct pt_regs *regs);
+long __x64_sys_getcpu(const struct pt_regs *regs);
+long __x64_sys_gettimeofday(const struct pt_regs *regs);
+long __x64_sys_time(const struct pt_regs *regs);
 
 #endif /* _ASM_X86_SYSCALL_WRAPPER_H */