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/* SPDX-License-Identifier: GPL-2.0 */
/*
* Copyright (C) 2020-2022 Loongson Technology Corporation Limited
*/
#ifndef _ASM_PTRACE_H
#define _ASM_PTRACE_H
#include <asm/page.h>
#include <asm/thread_info.h>
#include <uapi/asm/ptrace.h>
/*
* This struct defines the way the registers are stored on the stack during
* a system call/exception. If you add a register here, please also add it to
* regoffset_table[] in arch/loongarch/kernel/ptrace.c.
*/
struct pt_regs {
/* Main processor registers. */
unsigned long regs[32];
/* Original syscall arg0. */
unsigned long orig_a0;
/* Special CSR registers. */
unsigned long csr_era;
unsigned long csr_badvaddr;
unsigned long csr_crmd;
unsigned long csr_prmd;
unsigned long csr_euen;
unsigned long csr_ecfg;
unsigned long csr_estat;
unsigned long __last[];
} __aligned(8);
static inline int regs_irqs_disabled(struct pt_regs *regs)
{
return arch_irqs_disabled_flags(regs->csr_prmd);
}
static inline unsigned long kernel_stack_pointer(struct pt_regs *regs)
{
return regs->regs[3];
}
/*
* Don't use asm-generic/ptrace.h it defines FP accessors that don't make
* sense on LoongArch. We rather want an error if they get invoked.
*/
static inline void instruction_pointer_set(struct pt_regs *regs, unsigned long val)
{
regs->csr_era = val;
}
/* Query offset/name of register from its name/offset */
extern int regs_query_register_offset(const char *name);
#define MAX_REG_OFFSET (offsetof(struct pt_regs, __last))
/**
* regs_get_register() - get register value from its offset
* @regs: pt_regs from which register value is gotten.
* @offset: offset number of the register.
*
* regs_get_register returns the value of a register. The @offset is the
* offset of the register in struct pt_regs address which specified by @regs.
* If @offset is bigger than MAX_REG_OFFSET, this returns 0.
*/
static inline unsigned long regs_get_register(struct pt_regs *regs, unsigned int offset)
{
if (unlikely(offset > MAX_REG_OFFSET))
return 0;
return *(unsigned long *)((unsigned long)regs + offset);
}
/**
* regs_within_kernel_stack() - check the address in the stack
* @regs: pt_regs which contains kernel stack pointer.
* @addr: address which is checked.
*
* regs_within_kernel_stack() checks @addr is within the kernel stack page(s).
* If @addr is within the kernel stack, it returns true. If not, returns false.
*/
static inline int regs_within_kernel_stack(struct pt_regs *regs, unsigned long addr)
{
return ((addr & ~(THREAD_SIZE - 1)) ==
(kernel_stack_pointer(regs) & ~(THREAD_SIZE - 1)));
}
/**
* regs_get_kernel_stack_nth() - get Nth entry of the stack
* @regs: pt_regs which contains kernel stack pointer.
* @n: stack entry number.
*
* regs_get_kernel_stack_nth() returns @n th entry of the kernel stack which
* is specified by @regs. If the @n th entry is NOT in the kernel stack,
* this returns 0.
*/
static inline unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs, unsigned int n)
{
unsigned long *addr = (unsigned long *)kernel_stack_pointer(regs);
addr += n;
if (regs_within_kernel_stack(regs, (unsigned long)addr))
return *addr;
else
return 0;
}
struct task_struct;
/**
* regs_get_kernel_argument() - get Nth function argument in kernel
* @regs: pt_regs of that context
* @n: function argument number (start from 0)
*
* regs_get_argument() returns @n th argument of the function call.
* Note that this chooses most probably assignment, in some case
* it can be incorrect.
* This is expected to be called from kprobes or ftrace with regs
* where the top of stack is the return address.
*/
static inline unsigned long regs_get_kernel_argument(struct pt_regs *regs,
unsigned int n)
{
#define NR_REG_ARGUMENTS 8
static const unsigned int args[] = {
offsetof(struct pt_regs, regs[4]),
offsetof(struct pt_regs, regs[5]),
offsetof(struct pt_regs, regs[6]),
offsetof(struct pt_regs, regs[7]),
offsetof(struct pt_regs, regs[8]),
offsetof(struct pt_regs, regs[9]),
offsetof(struct pt_regs, regs[10]),
offsetof(struct pt_regs, regs[11]),
};
if (n < NR_REG_ARGUMENTS)
return regs_get_register(regs, args[n]);
else {
n -= NR_REG_ARGUMENTS;
return regs_get_kernel_stack_nth(regs, n);
}
}
/*
* Does the process account for user or for system time?
*/
#define user_mode(regs) (((regs)->csr_prmd & PLV_MASK) == PLV_USER)
static inline long regs_return_value(struct pt_regs *regs)
{
return regs->regs[4];
}
#define instruction_pointer(regs) ((regs)->csr_era)
#define profile_pc(regs) instruction_pointer(regs)
extern void die(const char *, struct pt_regs *) __noreturn;
static inline void die_if_kernel(const char *str, struct pt_regs *regs)
{
if (unlikely(!user_mode(regs)))
die(str, regs);
}
#define current_pt_regs() \
({ \
unsigned long sp = (unsigned long)__builtin_frame_address(0); \
(struct pt_regs *)((sp | (THREAD_SIZE - 1)) + 1) - 1; \
})
/* Helpers for working with the user stack pointer */
static inline unsigned long user_stack_pointer(struct pt_regs *regs)
{
return regs->regs[3];
}
static inline void user_stack_pointer_set(struct pt_regs *regs,
unsigned long val)
{
regs->regs[3] = val;
}
#endif /* _ASM_PTRACE_H */
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