x86/entry: Move max syscall number calculation to syscallhdr.sh

Instead of using an array in asm-offsets to calculate the max syscall
number, calculate it when writing out the syscall headers.

Signed-off-by: Brian Gerst <brgerst@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20200313195144.164260-9-brgerst@gmail.com

arch/x86/entry/syscall_32.c

@@ -4,7 +4,7 @@
 #include <linux/linkage.h>
 #include <linux/sys.h>
 #include <linux/cache.h>
-#include <asm/asm-offsets.h>
+#include <asm/unistd.h>
 #include <asm/syscall.h>
 
 #ifdef CONFIG_IA32_EMULATION
@@ -22,11 +22,11 @@ extern asmlinkage long sys_ni_syscall(unsigned long, unsigned long, unsigned lon
 
 #define __SYSCALL_I386(nr, sym, qual) [nr] = sym,
 
-__visible const sys_call_ptr_t ia32_sys_call_table[__NR_syscall_compat_max+1] = {
+__visible const sys_call_ptr_t ia32_sys_call_table[__NR_ia32_syscall_max+1] = {
 	/*
 	 * Smells like a compiler bug -- it doesn't work
 	 * when the & below is removed.
 	 */
-	[0 ... __NR_syscall_compat_max] = &__sys_ni_syscall,
+	[0 ... __NR_ia32_syscall_max] = &__sys_ni_syscall,
 #include <asm/syscalls_32.h>
 };

arch/x86/entry/syscall_64.c

@@ -5,7 +5,7 @@
 #include <linux/sys.h>
 #include <linux/cache.h>
 #include <linux/syscalls.h>
-#include <asm/asm-offsets.h>
+#include <asm/unistd.h>
 #include <asm/syscall.h>
 
 #define __SYSCALL_X32(nr, sym, qual)

arch/x86/entry/syscall_x32.c

@@ -5,7 +5,7 @@
 #include <linux/sys.h>
 #include <linux/cache.h>
 #include <linux/syscalls.h>
-#include <asm/asm-offsets.h>
+#include <asm/unistd.h>
 #include <asm/syscall.h>
 
 #define __SYSCALL_64(nr, sym, qual)
@@ -16,11 +16,11 @@
 
 #define __SYSCALL_X32(nr, sym, qual) [nr] = sym,
 
-asmlinkage const sys_call_ptr_t x32_sys_call_table[__NR_syscall_x32_max+1] = {
+asmlinkage const sys_call_ptr_t x32_sys_call_table[__NR_x32_syscall_max+1] = {
 	/*
 	 * Smells like a compiler bug -- it doesn't work
 	 * when the & below is removed.
 	 */
-	[0 ... __NR_syscall_x32_max] = &__x64_sys_ni_syscall,
+	[0 ... __NR_x32_syscall_max] = &__x64_sys_ni_syscall,
 #include <asm/syscalls_64.h>
 };

arch/x86/entry/syscalls/syscallhdr.sh

@@ -15,14 +15,21 @@ grep -E "^[0-9A-Fa-fXx]+[[:space:]]+${my_abis}" "$in" | sort -n | (
     echo "#define ${fileguard} 1"
     echo ""
 
+    max=0
     while read nr abi name entry ; do
 	if [ -z "$offset" ]; then
 	    echo "#define __NR_${prefix}${name} $nr"
 	else
 	    echo "#define __NR_${prefix}${name} ($offset + $nr)"
         fi
+
+	max=$nr
     done
 
+    echo ""
+    echo "#ifdef __KERNEL__"
+    echo "#define __NR_${prefix}syscall_max $max"
+    echo "#endif"
     echo ""
     echo "#endif /* ${fileguard} */"
 ) > "$out"

arch/x86/entry/vdso/vdso32/vclock_gettime.c

@@ -13,6 +13,7 @@
  */
 #undef CONFIG_64BIT
 #undef CONFIG_X86_64
+#undef CONFIG_COMPAT
 #undef CONFIG_PGTABLE_LEVELS
 #undef CONFIG_ILLEGAL_POINTER_VALUE
 #undef CONFIG_SPARSEMEM_VMEMMAP

arch/x86/include/asm/syscall.h

@@ -13,7 +13,6 @@
 #include <uapi/linux/audit.h>
 #include <linux/sched.h>
 #include <linux/err.h>
-#include <asm/asm-offsets.h>	/* For NR_syscalls */
 #include <asm/thread_info.h>	/* for TS_COMPAT */
 #include <asm/unistd.h>
 
@@ -28,8 +27,6 @@ extern const sys_call_ptr_t sys_call_table[];
 
 #if defined(CONFIG_X86_32)
 #define ia32_sys_call_table sys_call_table
-#define __NR_syscall_compat_max __NR_syscall_max
-#define IA32_NR_syscalls NR_syscalls
 #endif
 
 #if defined(CONFIG_IA32_EMULATION)

arch/x86/include/asm/unistd.h

@@ -13,10 +13,13 @@
 #  define __ARCH_WANT_SYS_OLD_MMAP
 #  define __ARCH_WANT_SYS_OLD_SELECT
 
+#  define __NR_ia32_syscall_max __NR_syscall_max
+
 # else
 
 #  include <asm/unistd_64.h>
 #  include <asm/unistd_64_x32.h>
+#  include <asm/unistd_32_ia32.h>
 #  define __ARCH_WANT_SYS_TIME
 #  define __ARCH_WANT_SYS_UTIME
 #  define __ARCH_WANT_COMPAT_SYS_PREADV64
@@ -26,6 +29,10 @@
 
 # endif
 
+# define NR_syscalls (__NR_syscall_max + 1)
+# define X32_NR_syscalls (__NR_x32_syscall_max + 1)
+# define IA32_NR_syscalls (__NR_ia32_syscall_max + 1)
+
 # define __ARCH_WANT_NEW_STAT
 # define __ARCH_WANT_OLD_READDIR
 # define __ARCH_WANT_OLD_STAT

arch/x86/kernel/asm-offsets_32.c

@@ -5,11 +5,6 @@
 
 #include <asm/ucontext.h>
 
-#define __SYSCALL_I386(nr, sym, qual) [nr] = 1,
-static char syscalls[] = {
-#include <asm/syscalls_32.h>
-};
-
 /* workaround for a warning with -Wmissing-prototypes */
 void foo(void);
 
@@ -60,8 +55,4 @@ void foo(void)
 	BLANK();
 	OFFSET(stack_canary_offset, stack_canary, canary);
 #endif
-
-	BLANK();
-	DEFINE(__NR_syscall_max, sizeof(syscalls) - 1);
-	DEFINE(NR_syscalls, sizeof(syscalls));
 }

arch/x86/kernel/asm-offsets_64.c

@@ -5,30 +5,6 @@
 
 #include <asm/ia32.h>
 
-#define __SYSCALL_64(nr, sym, qual) [nr] = 1,
-#define __SYSCALL_X32(nr, sym, qual)
-static char syscalls_64[] = {
-#include <asm/syscalls_64.h>
-};
-#undef __SYSCALL_64
-#undef __SYSCALL_X32
-
-#ifdef CONFIG_X86_X32_ABI
-#define __SYSCALL_64(nr, sym, qual)
-#define __SYSCALL_X32(nr, sym, qual) [nr] = 1,
-static char syscalls_x32[] = {
-#include <asm/syscalls_64.h>
-};
-#undef __SYSCALL_64
-#undef __SYSCALL_X32
-#endif
-
-#define __SYSCALL_I386(nr, sym, qual) [nr] = 1,
-static char syscalls_ia32[] = {
-#include <asm/syscalls_32.h>
-};
-#undef __SYSCALL_I386
-
 #if defined(CONFIG_KVM_GUEST) && defined(CONFIG_PARAVIRT_SPINLOCKS)
 #include <asm/kvm_para.h>
 #endif
@@ -90,17 +66,5 @@ int main(void)
 	DEFINE(stack_canary_offset, offsetof(struct fixed_percpu_data, stack_canary));
 	BLANK();
 #endif
-
-	DEFINE(__NR_syscall_max, sizeof(syscalls_64) - 1);
-	DEFINE(NR_syscalls, sizeof(syscalls_64));
-
-#ifdef CONFIG_X86_X32_ABI
-	DEFINE(__NR_syscall_x32_max, sizeof(syscalls_x32) - 1);
-	DEFINE(X32_NR_syscalls, sizeof(syscalls_x32));
-#endif
-
-	DEFINE(__NR_syscall_compat_max, sizeof(syscalls_ia32) - 1);
-	DEFINE(IA32_NR_syscalls, sizeof(syscalls_ia32));
-
 	return 0;
 }

arch/x86/um/sys_call_table_32.c

@@ -7,7 +7,7 @@
 #include <linux/linkage.h>
 #include <linux/sys.h>
 #include <linux/cache.h>
-#include <generated/user_constants.h>
+#include <asm/unistd.h>
 #include <asm/syscall.h>
 
 #define __NO_STUBS

arch/x86/um/sys_call_table_64.c

@@ -7,7 +7,7 @@
 #include <linux/linkage.h>
 #include <linux/sys.h>
 #include <linux/cache.h>
-#include <generated/user_constants.h>
+#include <asm/unistd.h>
 #include <asm/syscall.h>
 
 #define __NO_STUBS

arch/x86/um/user-offsets.c

@@ -9,18 +9,6 @@
 #include <linux/ptrace.h>
 #include <asm/types.h>
 
-#ifdef __i386__
-#define __SYSCALL_I386(nr, sym, qual) [nr] = 1,
-static char syscalls[] = {
-#include <asm/syscalls_32.h>
-};
-#else
-#define __SYSCALL_64(nr, sym, qual) [nr] = 1,
-static char syscalls[] = {
-#include <asm/syscalls_64.h>
-};
-#endif
-
 #define DEFINE(sym, val) \
 	asm volatile("\n->" #sym " %0 " #val : : "i" (val))
 
@@ -94,7 +82,4 @@ void foo(void)
 	DEFINE(UM_PROT_READ, PROT_READ);
 	DEFINE(UM_PROT_WRITE, PROT_WRITE);
 	DEFINE(UM_PROT_EXEC, PROT_EXEC);
-
-	DEFINE(__NR_syscall_max, sizeof(syscalls) - 1);
-	DEFINE(NR_syscalls, sizeof(syscalls));
 }