include/asm/syscall.h

0001 /* SPDX-License-Identifier: GPL-2.0-only */
0002 /*
0003  * Access to user system call parameters and results
0004  *
0005  * Copyright (C) 2008-2009 Red Hat, Inc.  All rights reserved.
0006  *
0007  * See asm-generic/syscall.h for descriptions of what we must do here.
0008  */
0009
0010 #ifndef _ASM_X86_SYSCALL_H
0011 #define _ASM_X86_SYSCALL_H
0012
0013 #include <uapi/linux/audit.h>
0014 #include <linux/sched.h>
0015 #include <linux/err.h>
0016 #include <asm/thread_info.h>    /* for TS_COMPAT */
0017 #include <asm/unistd.h>
0018
0019 typedef long (*sys_call_ptr_t)(const struct pt_regs *);
0020 extern const sys_call_ptr_t sys_call_table[];
0021
0022 #if defined(CONFIG_X86_32)
0023 #define ia32_sys_call_table sys_call_table
0024 #else
0025 /*
0026  * These may not exist, but still put the prototypes in so we
0027  * can use IS_ENABLED().
0028  */
0029 extern const sys_call_ptr_t ia32_sys_call_table[];
0030 extern const sys_call_ptr_t x32_sys_call_table[];
0031 #endif
0032
0033 /*
0034  * Only the low 32 bits of orig_ax are meaningful, so we return int.
0035  * This importantly ignores the high bits on 64-bit, so comparisons
0036  * sign-extend the low 32 bits.
0037  */
0038 static inline int syscall_get_nr(struct task_struct *task, struct pt_regs *regs)
0039 {
0040     return regs->orig_ax;
0041 }
0042
0043 static inline void syscall_rollback(struct task_struct *task,
0044                     struct pt_regs *regs)
0045 {
0046     regs->ax = regs->orig_ax;
0047 }
0048
0049 static inline long syscall_get_error(struct task_struct *task,
0050                      struct pt_regs *regs)
0051 {
0052     unsigned long error = regs->ax;
0053 #ifdef CONFIG_IA32_EMULATION
0054     /*
0055      * TS_COMPAT is set for 32-bit syscall entries and then
0056      * remains set until we return to user mode.
0057      */
0058     if (task->thread_info.status & (TS_COMPAT|TS_I386_REGS_POKED))
0059         /*
0060          * Sign-extend the value so (int)-EFOO becomes (long)-EFOO
0061          * and will match correctly in comparisons.
0062          */
0063         error = (long) (int) error;
0064 #endif
0065     return IS_ERR_VALUE(error) ? error : 0;
0066 }
0067
0068 static inline long syscall_get_return_value(struct task_struct *task,
0069                         struct pt_regs *regs)
0070 {
0071     return regs->ax;
0072 }
0073
0074 static inline void syscall_set_return_value(struct task_struct *task,
0075                         struct pt_regs *regs,
0076                         int error, long val)
0077 {
0078     regs->ax = (long) error ?: val;
0079 }
0080
0081 #ifdef CONFIG_X86_32
0082
0083 static inline void syscall_get_arguments(struct task_struct *task,
0084                      struct pt_regs *regs,
0085                      unsigned long *args)
0086 {
0087     memcpy(args, &regs->bx, 6 * sizeof(args[0]));
0088 }
0089
0090 static inline int syscall_get_arch(struct task_struct *task)
0091 {
0092     return AUDIT_ARCH_I386;
0093 }
0094
0095 #else    /* CONFIG_X86_64 */
0096
0097 static inline void syscall_get_arguments(struct task_struct *task,
0098                      struct pt_regs *regs,
0099                      unsigned long *args)
0100 {
0101 # ifdef CONFIG_IA32_EMULATION
0102     if (task->thread_info.status & TS_COMPAT) {
0103         *args++ = regs->bx;
0104         *args++ = regs->cx;
0105         *args++ = regs->dx;
0106         *args++ = regs->si;
0107         *args++ = regs->di;
0108         *args   = regs->bp;
0109     } else
0110 # endif
0111     {
0112         *args++ = regs->di;
0113         *args++ = regs->si;
0114         *args++ = regs->dx;
0115         *args++ = regs->r10;
0116         *args++ = regs->r8;
0117         *args   = regs->r9;
0118     }
0119 }
0120
0121 static inline int syscall_get_arch(struct task_struct *task)
0122 {
0123     /* x32 tasks should be considered AUDIT_ARCH_X86_64. */
0124     return (IS_ENABLED(CONFIG_IA32_EMULATION) &&
0125         task->thread_info.status & TS_COMPAT)
0126         ? AUDIT_ARCH_I386 : AUDIT_ARCH_X86_64;
0127 }
0128
0129 void do_syscall_64(struct pt_regs *regs, int nr);
0130 void do_int80_syscall_32(struct pt_regs *regs);
0131 long do_fast_syscall_32(struct pt_regs *regs);
0132
0133 #endif  /* CONFIG_X86_32 */
0134
0135 #endif  /* _ASM_X86_SYSCALL_H */