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Diffstat (limited to 'arch/nds32/include/asm/syscall.h')
| -rw-r--r-- | arch/nds32/include/asm/syscall.h | 164 |
1 files changed, 164 insertions, 0 deletions
diff --git a/arch/nds32/include/asm/syscall.h b/arch/nds32/include/asm/syscall.h new file mode 100644 index 000000000..7b5180d78 --- /dev/null +++ b/arch/nds32/include/asm/syscall.h @@ -0,0 +1,164 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +// Copyright (C) 2008-2009 Red Hat, Inc. All rights reserved. +// Copyright (C) 2005-2017 Andes Technology Corporation + +#ifndef _ASM_NDS32_SYSCALL_H +#define _ASM_NDS32_SYSCALL_H 1 + +#include <uapi/linux/audit.h> +#include <linux/err.h> +struct task_struct; +struct pt_regs; + +/** + * syscall_get_nr - find what system call a task is executing + * @task: task of interest, must be blocked + * @regs: task_pt_regs() of @task + * + * If @task is executing a system call or is at system call + * tracing about to attempt one, returns the system call number. + * If @task is not executing a system call, i.e. it's blocked + * inside the kernel for a fault or signal, returns -1. + * + * Note this returns int even on 64-bit machines. Only 32 bits of + * system call number can be meaningful. If the actual arch value + * is 64 bits, this truncates to 32 bits so 0xffffffff means -1. + * + * It's only valid to call this when @task is known to be blocked. + */ +static inline int +syscall_get_nr(struct task_struct *task, struct pt_regs *regs) +{ + return regs->syscallno; +} + +/** + * syscall_rollback - roll back registers after an aborted system call + * @task: task of interest, must be in system call exit tracing + * @regs: task_pt_regs() of @task + * + * It's only valid to call this when @task is stopped for system + * call exit tracing (due to TIF_SYSCALL_TRACE or TIF_SYSCALL_AUDIT), + * after tracehook_report_syscall_entry() returned nonzero to prevent + * the system call from taking place. + * + * This rolls back the register state in @regs so it's as if the + * system call instruction was a no-op. The registers containing + * the system call number and arguments are as they were before the + * system call instruction. This may not be the same as what the + * register state looked like at system call entry tracing. + */ +static inline void +syscall_rollback(struct task_struct *task, struct pt_regs *regs) +{ + regs->uregs[0] = regs->orig_r0; +} + +/** + * syscall_get_error - check result of traced system call + * @task: task of interest, must be blocked + * @regs: task_pt_regs() of @task + * + * Returns 0 if the system call succeeded, or -ERRORCODE if it failed. + * + * It's only valid to call this when @task is stopped for tracing on exit + * from a system call, due to %TIF_SYSCALL_TRACE or %TIF_SYSCALL_AUDIT. + */ +static inline long +syscall_get_error(struct task_struct *task, struct pt_regs *regs) +{ + unsigned long error = regs->uregs[0]; + return IS_ERR_VALUE(error) ? error : 0; +} + +/** + * syscall_get_return_value - get the return value of a traced system call + * @task: task of interest, must be blocked + * @regs: task_pt_regs() of @task + * + * Returns the return value of the successful system call. + * This value is meaningless if syscall_get_error() returned nonzero. + * + * It's only valid to call this when @task is stopped for tracing on exit + * from a system call, due to %TIF_SYSCALL_TRACE or %TIF_SYSCALL_AUDIT. + */ +static inline long +syscall_get_return_value(struct task_struct *task, struct pt_regs *regs) +{ + return regs->uregs[0]; +} + +/** + * syscall_set_return_value - change the return value of a traced system call + * @task: task of interest, must be blocked + * @regs: task_pt_regs() of @task + * @error: negative error code, or zero to indicate success + * @val: user return value if @error is zero + * + * This changes the results of the system call that user mode will see. + * If @error is zero, the user sees a successful system call with a + * return value of @val. If @error is nonzero, it's a negated errno + * code; the user sees a failed system call with this errno code. + * + * It's only valid to call this when @task is stopped for tracing on exit + * from a system call, due to %TIF_SYSCALL_TRACE or %TIF_SYSCALL_AUDIT. + */ +static inline void +syscall_set_return_value(struct task_struct *task, struct pt_regs *regs, + int error, long val) +{ + regs->uregs[0] = (long)error ? error : val; +} + +/** + * syscall_get_arguments - extract system call parameter values + * @task: task of interest, must be blocked + * @regs: task_pt_regs() of @task + * @args: array filled with argument values + * + * Fetches 6 arguments to the system call (from 0 through 5). The first + * argument is stored in @args[0], and so on. + * + * It's only valid to call this when @task is stopped for tracing on + * entry to a system call, due to %TIF_SYSCALL_TRACE or %TIF_SYSCALL_AUDIT. + */ +#define SYSCALL_MAX_ARGS 6 +static inline void +syscall_get_arguments(struct task_struct *task, struct pt_regs *regs, + unsigned long *args) +{ + args[0] = regs->orig_r0; + args++; + memcpy(args, ®s->uregs[0] + 1, 5 * sizeof(args[0])); +} + +/** + * syscall_set_arguments - change system call parameter value + * @task: task of interest, must be in system call entry tracing + * @regs: task_pt_regs() of @task + * @args: array of argument values to store + * + * Changes 6 arguments to the system call. The first argument gets value + * @args[0], and so on. + * + * It's only valid to call this when @task is stopped for tracing on + * entry to a system call, due to %TIF_SYSCALL_TRACE or %TIF_SYSCALL_AUDIT. + */ +static inline void +syscall_set_arguments(struct task_struct *task, struct pt_regs *regs, + const unsigned long *args) +{ + regs->orig_r0 = args[0]; + args++; + + memcpy(®s->uregs[0] + 1, args, 5 * sizeof(args[0])); +} + +static inline int +syscall_get_arch(struct task_struct *task) +{ + return IS_ENABLED(CONFIG_CPU_BIG_ENDIAN) + ? AUDIT_ARCH_NDS32BE : AUDIT_ARCH_NDS32; +} + +#endif /* _ASM_NDS32_SYSCALL_H */ |