syscalls/x86: Unconditionally enable 'struct pt_regs' based syscalls on x86_64

Removing CONFIG_SYSCALL_PTREGS from arch/x86/Kconfig and simply selecting
ARCH_HAS_SYSCALL_WRAPPER unconditionally on x86-64 allows us to simplify
several codepaths.

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/20180405095307.3730-7-linux@dominikbrodowski.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 7bbd6a174722c6506b0ba458dc14be281b9e3484..bcdd3e0e2ef5db6400477357639aeff9b24c6653 100644 (file)
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -29,6 +29,7 @@ config X86_64
        select HAVE_ARCH_SOFT_DIRTY
        select MODULES_USE_ELF_RELA
        select X86_DEV_DMA_OPS
+       select ARCH_HAS_SYSCALL_WRAPPER
 
 #
 # Arch settings
@@ -2954,8 +2955,3 @@ source "crypto/Kconfig"
 source "arch/x86/kvm/Kconfig"
 
 source "lib/Kconfig"
-
-config SYSCALL_PTREGS
-       def_bool y
-       depends on X86_64
-       select ARCH_HAS_SYSCALL_WRAPPER

diff --git a/arch/x86/entry/common.c b/arch/x86/entry/common.c
index 425f798b39e333706edfd88adde865314d5a98fc..fbf6a6c3fd2d5e94d44b0bd32b48bf4fa2bead6a 100644 (file)
--- a/arch/x86/entry/common.c
+++ b/arch/x86/entry/common.c
@@ -284,13 +284,7 @@ __visible void do_syscall_64(unsigned long nr, struct pt_regs *regs)
        nr &= __SYSCALL_MASK;
        if (likely(nr < NR_syscalls)) {
                nr = array_index_nospec(nr, NR_syscalls);
-#ifdef CONFIG_SYSCALL_PTREGS
                regs->ax = sys_call_table[nr](regs);
-#else
-               regs->ax = sys_call_table[nr](
-                       regs->di, regs->si, regs->dx,
-                       regs->r10, regs->r8, regs->r9);
-#endif
        }
 
        syscall_return_slowpath(regs);
@@ -325,7 +319,7 @@ static __always_inline void do_syscall_32_irqs_on(struct pt_regs *regs)
 
        if (likely(nr < IA32_NR_syscalls)) {
                nr = array_index_nospec(nr, IA32_NR_syscalls);
-#ifdef CONFIG_SYSCALL_PTREGS
+#ifdef CONFIG_IA32_EMULATION
                regs->ax = ia32_sys_call_table[nr](regs);
 #else
                /*
@@ -338,7 +332,7 @@ static __always_inline void do_syscall_32_irqs_on(struct pt_regs *regs)
                        (unsigned int)regs->bx, (unsigned int)regs->cx,
                        (unsigned int)regs->dx, (unsigned int)regs->si,
                        (unsigned int)regs->di, (unsigned int)regs->bp);
-#endif /* CONFIG_SYSCALL_PTREGS */
+#endif /* CONFIG_IA32_EMULATION */
        }
 
        syscall_return_slowpath(regs);

diff --git a/arch/x86/entry/syscall_32.c b/arch/x86/entry/syscall_32.c
index 47060dd8efb1113b55e69266c7bf62f000fbcfaf..aa3336a7cb150ccf170d4356f113c2fb7fb12292 100644 (file)
--- a/arch/x86/entry/syscall_32.c
+++ b/arch/x86/entry/syscall_32.c
@@ -7,17 +7,17 @@
 #include <asm/asm-offsets.h>
 #include <asm/syscall.h>
 
-#ifdef CONFIG_SYSCALL_PTREGS
+#ifdef CONFIG_IA32_EMULATION
 /* On X86_64, we use struct pt_regs * to pass parameters to syscalls */
 #define __SYSCALL_I386(nr, sym, qual) extern asmlinkage long sym(const struct pt_regs *);
 
 /* this is a lie, but it does not hurt as sys_ni_syscall just returns -EINVAL */
 extern asmlinkage long sys_ni_syscall(const struct pt_regs *);
 
-#else /* CONFIG_SYSCALL_PTREGS */
+#else /* CONFIG_IA32_EMULATION */
 #define __SYSCALL_I386(nr, sym, qual) extern asmlinkage long sym(unsigned long, unsigned long, unsigned long, unsigned long, unsigned long, unsigned long);
 extern asmlinkage long sys_ni_syscall(unsigned long, unsigned long, unsigned long, unsigned long, unsigned long, unsigned long);
-#endif /* CONFIG_SYSCALL_PTREGS */
+#endif /* CONFIG_IA32_EMULATION */
 
 #include <asm/syscalls_32.h>
 #undef __SYSCALL_I386

diff --git a/arch/x86/entry/syscall_64.c b/arch/x86/entry/syscall_64.c
index 6197850adf9194540f6ce3bdb371c7ff8ef860bf..d5252bc1e38058ebc2d071d9bd3b3bd3cc1a976a 100644 (file)
--- a/arch/x86/entry/syscall_64.c
+++ b/arch/x86/entry/syscall_64.c
@@ -7,14 +7,9 @@
 #include <asm/asm-offsets.h>
 #include <asm/syscall.h>
 
-#ifdef CONFIG_SYSCALL_PTREGS
 /* this is a lie, but it does not hurt as sys_ni_syscall just returns -EINVAL */
 extern asmlinkage long sys_ni_syscall(const struct pt_regs *);
 #define __SYSCALL_64(nr, sym, qual) extern asmlinkage long sym(const struct pt_regs *);
-#else /* CONFIG_SYSCALL_PTREGS */
-extern asmlinkage long sys_ni_syscall(unsigned long, unsigned long, unsigned long, unsigned long, unsigned long, unsigned long);
-#define __SYSCALL_64(nr, sym, qual) extern asmlinkage long sym(unsigned long, unsigned long, unsigned long, unsigned long, unsigned long, unsigned long);
-#endif /* CONFIG_SYSCALL_PTREGS */
 #include <asm/syscalls_64.h>
 #undef __SYSCALL_64
 

diff --git a/arch/x86/entry/vsyscall/vsyscall_64.c b/arch/x86/entry/vsyscall/vsyscall_64.c
index 05eebbf9b989f3f8bb7738c0cd5e63a4efe2891b..20b3d4a88ee446d572724dc8e7490bf700c19391 100644 (file)
--- a/arch/x86/entry/vsyscall/vsyscall_64.c
+++ b/arch/x86/entry/vsyscall/vsyscall_64.c
@@ -127,9 +127,7 @@ bool emulate_vsyscall(struct pt_regs *regs, unsigned long address)
        int vsyscall_nr, syscall_nr, tmp;
        int prev_sig_on_uaccess_err;
        long ret;
-#ifdef CONFIG_SYSCALL_PTREGS
        unsigned long orig_dx;
-#endif
 
        /*
         * No point in checking CS -- the only way to get here is a user mode
@@ -230,38 +228,22 @@ bool emulate_vsyscall(struct pt_regs *regs, unsigned long address)
        ret = -EFAULT;
        switch (vsyscall_nr) {
        case 0:
-#ifdef CONFIG_SYSCALL_PTREGS
                /* this decodes regs->di and regs->si on its own */
                ret = sys_gettimeofday(regs);
-#else
-               ret = sys_gettimeofday(
-                       (struct timeval __user *)regs->di,
-                       (struct timezone __user *)regs->si);
-#endif /* CONFIG_SYSCALL_PTREGS */
                break;
 
        case 1:
-#ifdef CONFIG_SYSCALL_PTREGS
                /* this decodes regs->di on its own */
                ret = sys_time(regs);
-#else
-               ret = sys_time((time_t __user *)regs->di);
-#endif /* CONFIG_SYSCALL_PTREGS */
                break;
 
        case 2:
-#ifdef CONFIG_SYSCALL_PTREGS
                /* while we could clobber regs->dx, we didn't in the past... */
                orig_dx = regs->dx;
                regs->dx = 0;
                /* this decodes regs->di, regs->si and regs->dx on its own */
                ret = sys_getcpu(regs);
                regs->dx = orig_dx;
-#else
-               ret = sys_getcpu((unsigned __user *)regs->di,
-                                (unsigned __user *)regs->si,
-                                NULL);
-#endif /* CONFIG_SYSCALL_PTREGS */
                break;
        }
 

diff --git a/arch/x86/include/asm/syscall.h b/arch/x86/include/asm/syscall.h
index 17c62373a6f900a96942b8b8380b95e371703304..d653139857af2a1121f877b611c8d56d4e4690f0 100644 (file)
--- a/arch/x86/include/asm/syscall.h
+++ b/arch/x86/include/asm/syscall.h
@@ -20,13 +20,13 @@
 #include <asm/thread_info.h>   /* for TS_COMPAT */
 #include <asm/unistd.h>
 
-#ifdef CONFIG_SYSCALL_PTREGS
+#ifdef CONFIG_X86_64
 typedef asmlinkage long (*sys_call_ptr_t)(const struct pt_regs *);
 #else
 typedef asmlinkage long (*sys_call_ptr_t)(unsigned long, unsigned long,
                                          unsigned long, unsigned long,
                                          unsigned long, unsigned long);
-#endif /* CONFIG_SYSCALL_PTREGS */
+#endif /* CONFIG_X86_64 */
 extern const sys_call_ptr_t sys_call_table[];
 
 #if defined(CONFIG_X86_32)

diff --git a/arch/x86/include/asm/syscalls.h b/arch/x86/include/asm/syscalls.h
index e4ad93c05f0209fdc77a5cd294ad8e02b4f5d3b0..d4d18d94695cc68c19e9a35bf7c37156a214c38c 100644 (file)
--- a/arch/x86/include/asm/syscalls.h
+++ b/arch/x86/include/asm/syscalls.h
@@ -19,10 +19,10 @@
 /* kernel/ioport.c */
 long ksys_ioperm(unsigned long from, unsigned long num, int turn_on);
 
-#ifndef CONFIG_SYSCALL_PTREGS
-/*
- * If CONFIG_SYSCALL_PTREGS is enabled, a different syscall calling convention
- * is used. Do not include these -- invalid -- prototypes then
+#ifdef CONFIG_X86_32
+/* 
+ * These definitions are only valid on pure 32-bit systems; x86-64 uses a
+ * different syscall calling convention
  */
 asmlinkage long sys_ioperm(unsigned long, unsigned long, int);
 asmlinkage long sys_iopl(unsigned int);
@@ -38,7 +38,6 @@ asmlinkage long sys_set_thread_area(struct user_desc __user *);
 asmlinkage long sys_get_thread_area(struct user_desc __user *);
 
 /* X86_32 only */
-#ifdef CONFIG_X86_32
 
 /* kernel/signal.c */
 asmlinkage long sys_sigreturn(void);
@@ -48,16 +47,5 @@ struct vm86_struct;
 asmlinkage long sys_vm86old(struct vm86_struct __user *);
 asmlinkage long sys_vm86(unsigned long, unsigned long);
 
-#else /* CONFIG_X86_32 */
-
-/* X86_64 only */
-/* kernel/process_64.c */
-asmlinkage long sys_arch_prctl(int, unsigned long);
-
-/* kernel/sys_x86_64.c */
-asmlinkage long sys_mmap(unsigned long, unsigned long, unsigned long,
-                        unsigned long, unsigned long, unsigned long);
-
 #endif /* CONFIG_X86_32 */
-#endif /* CONFIG_SYSCALL_PTREGS */
 #endif /* _ASM_X86_SYSCALLS_H */