linux kernel使用技巧教程

技巧

• • • • 1、 在linux kernel中读写ARM寄存器示例
      • 2、 在optee中读写ARM寄存器示例
      • 3、自定义log打印函数

1、 在linux kernel中读写ARM寄存器示例

#define FUNCTION_INVARIANT(reg)                        \
    static void get_##reg(struct kvm_vcpu *v,            \
                  const struct sys_reg_desc *r)        \
    {                                \
        u64 val;                        \
                                    \
        asm volatile("mrs %0, " __stringify(reg) "\n"        \
                 : "=r" (val));                \
        ((struct sys_reg_desc *)r)->val = val;            \
    }

FUNCTION_INVARIANT(midr_el1)
FUNCTION_INVARIANT(ctr_el0)
FUNCTION_INVARIANT(revidr_el1)
FUNCTION_INVARIANT(id_pfr0_el1)
FUNCTION_INVARIANT(id_pfr1_el1)
FUNCTION_INVARIANT(id_dfr0_el1)
FUNCTION_INVARIANT(id_afr0_el1)
FUNCTION_INVARIANT(id_mmfr0_el1)
FUNCTION_INVARIANT(id_mmfr1_el1)
FUNCTION_INVARIANT(id_mmfr2_el1)
FUNCTION_INVARIANT(id_mmfr3_el1)
FUNCTION_INVARIANT(id_isar0_el1)
FUNCTION_INVARIANT(id_isar1_el1)
FUNCTION_INVARIANT(id_isar2_el1)
FUNCTION_INVARIANT(id_isar3_el1)
FUNCTION_INVARIANT(id_isar4_el1)
FUNCTION_INVARIANT(id_isar5_el1)
FUNCTION_INVARIANT(clidr_el1)
FUNCTION_INVARIANT(aidr_el1)

2、 在optee中读写ARM寄存器示例

#define DEFINE_REG_READ_FUNC_(reg, type, asmreg)    \
static inline type read_##reg(void)            \
{                            \
    type val;                    \
                            \
    asm volatile("mrs %0, " #asmreg : "=r" (val));    \
    return val;                    \
}

#define DEFINE_REG_WRITE_FUNC_(reg, type, asmreg)        \
static inline void write_##reg(type val)            \
{                                \
    asm volatile("msr " #asmreg ", %0" : : "r" (val));    \
}

#define DEFINE_U32_REG_READ_FUNC(reg) \
        DEFINE_REG_READ_FUNC_(reg, uint32_t, reg)

#define DEFINE_U32_REG_WRITE_FUNC(reg) \
        DEFINE_REG_WRITE_FUNC_(reg, uint32_t, reg)

#define DEFINE_U32_REG_READWRITE_FUNCS(reg)    \
        DEFINE_U32_REG_READ_FUNC(reg)    \
        DEFINE_U32_REG_WRITE_FUNC(reg)

#define DEFINE_U64_REG_READ_FUNC(reg) \
        DEFINE_REG_READ_FUNC_(reg, uint64_t, reg)

#define DEFINE_U64_REG_WRITE_FUNC(reg) \
        DEFINE_REG_WRITE_FUNC_(reg, uint64_t, reg)

#define DEFINE_U64_REG_READWRITE_FUNCS(reg)    \
        DEFINE_U64_REG_READ_FUNC(reg)    \
        DEFINE_U64_REG_WRITE_FUNC(reg)

DEFINE_U32_REG_READWRITE_FUNCS(cpacr_el1)
DEFINE_U32_REG_READWRITE_FUNCS(daif)
DEFINE_U32_REG_READWRITE_FUNCS(fpcr)
DEFINE_U32_REG_READWRITE_FUNCS(fpsr)

DEFINE_U32_REG_READ_FUNC(contextidr_el1)
DEFINE_U32_REG_READ_FUNC(sctlr_el1)

/* ARM Generic timer functions */
DEFINE_REG_READ_FUNC_(cntfrq, uint32_t, cntfrq_el0)
DEFINE_REG_READ_FUNC_(cntpct, uint64_t, cntpct_el0)
DEFINE_REG_READ_FUNC_(cntkctl, uint32_t, cntkctl_el1)
DEFINE_REG_WRITE_FUNC_(cntkctl, uint32_t, cntkctl_el1)

DEFINE_U64_REG_READWRITE_FUNCS(ttbr0_el1)
DEFINE_U64_REG_READWRITE_FUNCS(ttbr1_el1)
DEFINE_U64_REG_READWRITE_FUNCS(tcr_el1)

DEFINE_U64_REG_READ_FUNC(esr_el1)
DEFINE_U64_REG_READ_FUNC(far_el1)
DEFINE_U64_REG_READ_FUNC(mpidr_el1)
DEFINE_U64_REG_READ_FUNC(midr_el1)
/* Alias for reading this register to avoid ifdefs in code */
#define read_midr() read_midr_el1()
DEFINE_U64_REG_READ_FUNC(par_el1)

DEFINE_U64_REG_WRITE_FUNC(mair_el1)

/* Register read/write functions for GICC registers by using system interface */
DEFINE_REG_READ_FUNC_(icc_ctlr, uint32_t, S3_0_C12_C12_4)
DEFINE_REG_WRITE_FUNC_(icc_ctlr, uint32_t, S3_0_C12_C12_4)
DEFINE_REG_WRITE_FUNC_(icc_pmr, uint32_t, S3_0_C4_C6_0)
DEFINE_REG_READ_FUNC_(icc_iar0, uint32_t, S3_0_c12_c8_0)
DEFINE_REG_READ_FUNC_(icc_iar1, uint32_t, S3_0_c12_c12_0)
DEFINE_REG_WRITE_FUNC_(icc_eoir0, uint32_t, S3_0_c12_c8_1)
DEFINE_REG_WRITE_FUNC_(icc_eoir1, uint32_t, S3_0_c12_c12_1)

3、自定义log打印函数

#define XXXX_PRINTK(fmt, ...)           ALOGI(fmt, ##__VA_ARGS__)
#define XXXX_ENTER()           XXXX_PRINTK("%d : %s :enter",__LINE__, __func__)
#define XXXX_EXIT()           XXXX_PRINTK("%d : %s :exit",__LINE__, __func__)