(2015/01/12 21:51), Steve Capper wrote:
> On Sat, Jan 10, 2015 at 11:03:16PM -0500, David Long wrote:
>> From: "David A. Long" <dave.l...@linaro.org>
>>
>> Add HAVE_REGS_AND_STACK_ACCESS_API feature for arm64.
>>
>> Signed-off-by: David A. Long <dave.l...@linaro.org>
>> ---
>>  arch/arm64/Kconfig                   |   1 +
>>  arch/arm64/include/asm/ptrace.h      |  29 +++++++++
>>  arch/arm64/include/uapi/asm/ptrace.h |  36 +++++++++++
>>  arch/arm64/kernel/ptrace.c           | 119 
>> +++++++++++++++++++++++++++++++++++
>>  4 files changed, 185 insertions(+)
>>
>> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
>> index b1f9a20..12b3fd6 100644
>> --- a/arch/arm64/Kconfig
>> +++ b/arch/arm64/Kconfig
>> @@ -64,6 +64,7 @@ config ARM64
>>      select HAVE_PERF_EVENTS
>>      select HAVE_PERF_REGS
>>      select HAVE_PERF_USER_STACK_DUMP
>> +    select HAVE_REGS_AND_STACK_ACCESS_API
>>      select HAVE_RCU_TABLE_FREE
>>      select HAVE_SYSCALL_TRACEPOINTS
>>      select IRQ_DOMAIN
>> diff --git a/arch/arm64/include/asm/ptrace.h 
>> b/arch/arm64/include/asm/ptrace.h
>> index 41ed9e1..3613e49 100644
>> --- a/arch/arm64/include/asm/ptrace.h
>> +++ b/arch/arm64/include/asm/ptrace.h
>> @@ -111,6 +111,8 @@ struct pt_regs {
>>      u64 syscallno;
>>  };
>>  
>> +#define MAX_REG_OFFSET (sizeof(struct user_pt_regs) - sizeof(u64))
>> +
>>  #define arch_has_single_step()      (1)
>>  
>>  #ifdef CONFIG_COMPAT
>> @@ -139,11 +141,38 @@ struct pt_regs {
>>  #define user_stack_pointer(regs) \
>>      (!compat_user_mode(regs) ? (regs)->sp : (regs)->compat_sp)
>>  
>> +/**
>> + * 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 whose offset from 
>> @regs.
>> + * The @offset is the offset of the register in struct pt_regs.
>> + * If @offset is bigger than MAX_REG_OFFSET, this returns 0.
>> + */
>> +static inline u64 regs_get_register(struct pt_regs *regs,
>> +                                          unsigned int offset)
>> +{
>> +    if (unlikely(offset > MAX_REG_OFFSET))
>> +            return 0;
>> +    return *(u64 *)((u64)regs + offset);
>> +}
>> +
>> +/* Valid only for Kernel mode traps. */
>> +static inline unsigned long kernel_stack_pointer(struct pt_regs *regs)
>> +{
>> +    return regs->ARM_sp;
>> +}
>> +
>>  static inline unsigned long regs_return_value(struct pt_regs *regs)
>>  {
>>      return regs->regs[0];
>>  }
>>  
>> +extern int regs_query_register_offset(const char *name);
>> +extern unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs,
>> +                                           unsigned int n);
>> +
>>  /*
>>   * Are the current registers suitable for user mode? (used to maintain
>>   * security in signal handlers)
>> diff --git a/arch/arm64/include/uapi/asm/ptrace.h 
>> b/arch/arm64/include/uapi/asm/ptrace.h
>> index 6913643..700d28b 100644
>> --- a/arch/arm64/include/uapi/asm/ptrace.h
>> +++ b/arch/arm64/include/uapi/asm/ptrace.h
>> @@ -61,6 +61,42 @@
>>  
>>  #ifndef __ASSEMBLY__
>>  
>> +#define ARM_cpsr    pstate
>> +#define ARM_pc              pc
>> +#define ARM_sp              sp
>> +#define ARM_lr              regs[30]
>> +#define ARM_fp              regs[29]
>> +#define ARM_x28             regs[28]
>> +#define ARM_x27             regs[27]
>> +#define ARM_x26             regs[26]
>> +#define ARM_x25             regs[25]
>> +#define ARM_x24             regs[24]
>> +#define ARM_x23             regs[23]
>> +#define ARM_x22             regs[22]
>> +#define ARM_x21             regs[21]
>> +#define ARM_x20             regs[20]
>> +#define ARM_x19             regs[19]
>> +#define ARM_x18             regs[18]
>> +#define ARM_ip1             regs[17]
>> +#define ARM_ip0             regs[16]
>> +#define ARM_x15             regs[15]
>> +#define ARM_x14             regs[14]
>> +#define ARM_x13             regs[13]
>> +#define ARM_x12             regs[12]
>> +#define ARM_x11             regs[11]
>> +#define ARM_x10             regs[10]
>> +#define ARM_x9              regs[9]
>> +#define ARM_x8              regs[8]
>> +#define ARM_x7              regs[7]
>> +#define ARM_x6              regs[6]
>> +#define ARM_x5              regs[5]
>> +#define ARM_x4              regs[4]
>> +#define ARM_x3              regs[3]
>> +#define ARM_x2              regs[2]
>> +#define ARM_x1              regs[1]
>> +#define ARM_x0              regs[0]
>> +#define ARM_ORIG_x0 orig_x0
>> +
>>  /*
>>   * User structures for general purpose, floating point and debug registers.
>>   */
>> diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c
>> index d882b83..9115b25 100644
>> --- a/arch/arm64/kernel/ptrace.c
>> +++ b/arch/arm64/kernel/ptrace.c
>> @@ -48,6 +48,125 @@
>>  #define CREATE_TRACE_POINTS
>>  #include <trace/events/syscalls.h>
>>  
>> +struct pt_regs_offset {
>> +    const char *name;
>> +    int offset;
>> +};
>> +
>> +#define REG_OFFSET_NAME(r) \
>> +    {.name = #r, .offset = offsetof(struct pt_regs, ARM_##r)}
>> +#define REG_OFFSET_END {.name = NULL, .offset = 0}
>> +
>> +static const struct pt_regs_offset regoffset_table[] = {
>> +    REG_OFFSET_NAME(x0),
>> +    REG_OFFSET_NAME(x1),
>> +    REG_OFFSET_NAME(x2),
>> +    REG_OFFSET_NAME(x3),
>> +    REG_OFFSET_NAME(x4),
>> +    REG_OFFSET_NAME(x5),
>> +    REG_OFFSET_NAME(x6),
>> +    REG_OFFSET_NAME(x7),
>> +    REG_OFFSET_NAME(x8),
>> +    REG_OFFSET_NAME(x9),
>> +    REG_OFFSET_NAME(x10),
>> +    REG_OFFSET_NAME(x11),
>> +    REG_OFFSET_NAME(x12),
>> +    REG_OFFSET_NAME(x13),
>> +    REG_OFFSET_NAME(x14),
>> +    REG_OFFSET_NAME(x15),
>> +    REG_OFFSET_NAME(ip0),
>> +    REG_OFFSET_NAME(ip1),
>> +    REG_OFFSET_NAME(x18),
>> +    REG_OFFSET_NAME(x19),
>> +    REG_OFFSET_NAME(x20),
>> +    REG_OFFSET_NAME(x21),
>> +    REG_OFFSET_NAME(x22),
>> +    REG_OFFSET_NAME(x23),
>> +    REG_OFFSET_NAME(x24),
>> +    REG_OFFSET_NAME(x25),
>> +    REG_OFFSET_NAME(x26),
>> +    REG_OFFSET_NAME(x27),
>> +    REG_OFFSET_NAME(x28),
>> +    REG_OFFSET_NAME(fp),
>> +    REG_OFFSET_NAME(lr),
>> +/*
>> +    REG_OFFSET_NAME(ip),
>> +*/
> 
> Should this comment block be removed?

Agreed, I think it should be removed.
Except that, this looks good to me.

Reviewed-by: Masami Hiramatsu <masami.hiramatsu...@hitachi.com>

Thanks!

> 
>> +    REG_OFFSET_NAME(sp),
>> +    REG_OFFSET_NAME(pc),
>> +    REG_OFFSET_NAME(cpsr),
>> +    REG_OFFSET_NAME(ORIG_x0),
>> +    REG_OFFSET_END,
>> +};
>> +
>> +/**
>> + * regs_query_register_offset() - query register offset from its name
>> + * @name:   the name of a register
>> + *
>> + * regs_query_register_offset() returns the offset of a register in struct
>> + * pt_regs from its name. If the name is invalid, this returns -EINVAL;
>> + */
>> +int regs_query_register_offset(const char *name)
>> +{
>> +    const struct pt_regs_offset *roff;
>> +
>> +    for (roff = regoffset_table; roff->name != NULL; roff++)
>> +            if (!strcmp(roff->name, name))
>> +                    return roff->offset;
>> +    return -EINVAL;
>> +}
>> +
>> +/**
>> + * regs_query_register_name() - query register name from its offset
>> + * @offset: the offset of a register in struct pt_regs.
>> + *
>> + * regs_query_register_name() returns the name of a register from its
>> + * offset in struct pt_regs. If the @offset is invalid, this returns NULL;
>> + */
>> +const char *regs_query_register_name(unsigned int offset)
>> +{
>> +    const struct pt_regs_offset *roff;
>> +
>> +    for (roff = regoffset_table; roff->name != NULL; roff++)
>> +            if (roff->offset == offset)
>> +                    return roff->name;
>> +    return NULL;
>> +}
>> +
>> +/**
>> + * 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.
>> + */
>> +bool 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.
>> + */
>> +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;
>> +}
>> +
>>  /*
>>   * TODO: does not yet catch signals sent when the child dies.
>>   * in exit.c or in signal.c.
>> -- 
>> 1.8.1.2
>>
> 


-- 
Masami HIRAMATSU
Software Platform Research Dept. Linux Technology Research Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: masami.hiramatsu...@hitachi.com


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