Re: [PATCH v4 1/6] arm64: Add HAVE_REGS_AND_STACK_ACCESS_API feature

From: Masami Hiramatsu
Date: Thu Jan 15 2015 - 02:07:22 EST

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(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.long@xxxxxxxxxx>
>>
>> Add HAVE_REGS_AND_STACK_ACCESS_API feature for arm64.
>>
>> Signed-off-by: David A. Long <dave.long@xxxxxxxxxx>
>> ---
>> 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.pt@xxxxxxxxxxx>

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.pt@xxxxxxxxxxx

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Next message: Davidlohr Bueso: "[PATCH] sound/oss: use current->state helpers"
Previous message: Stephen Rothwell: "linux-next: Tree for Jan 15"
In reply to: Steve Capper: "Re: [PATCH v4 1/6] arm64: Add HAVE_REGS_AND_STACK_ACCESS_API feature"
Next in thread: David Long: "[PATCH v4 5/6] arm64: Add kernel return probes support(kretprobes)"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]