[PATCH v13 01/10] arm64: Add HAVE_REGS_AND_STACK_ACCESS_API feature
Li Bin
huawei.libin at huawei.com
Sun Jun 19 19:43:12 PDT 2016
on 2016/6/3 11:26, David Long wrote:
> From: "David A. Long" <dave.long at linaro.org>
>
> Add HAVE_REGS_AND_STACK_ACCESS_API feature for arm64, including supporting
> functions and defines.
>
> Signed-off-by: David A. Long <dave.long at linaro.org>
> ---
> arch/arm64/Kconfig | 1 +
> arch/arm64/include/asm/ptrace.h | 54 +++++++++++++++++-
> arch/arm64/kernel/ptrace.c | 118 ++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 172 insertions(+), 1 deletion(-)
>
> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
> index 76747d9..0f7a624 100644
> --- a/arch/arm64/Kconfig
> +++ b/arch/arm64/Kconfig
> @@ -85,6 +85,7 @@ 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 IOMMU_DMA if IOMMU_SUPPORT
> diff --git a/arch/arm64/include/asm/ptrace.h b/arch/arm64/include/asm/ptrace.h
> index a307eb6..c130f2b 100644
> --- a/arch/arm64/include/asm/ptrace.h
> +++ b/arch/arm64/include/asm/ptrace.h
> @@ -74,6 +74,7 @@
> #define COMPAT_PT_DATA_ADDR 0x10004
> #define COMPAT_PT_TEXT_END_ADDR 0x10008
> #ifndef __ASSEMBLY__
> +#include <linux/bug.h>
>
> /* sizeof(struct user) for AArch32 */
> #define COMPAT_USER_SZ 296
> @@ -119,6 +120,8 @@ struct pt_regs {
> u64 syscallno;
> };
>
> +#define MAX_REG_OFFSET offsetof(struct pt_regs, pstate)
> +
> #define arch_has_single_step() (1)
>
> #ifdef CONFIG_COMPAT
> @@ -147,6 +150,55 @@ struct pt_regs {
> #define user_stack_pointer(regs) \
> (!compat_user_mode(regs) ? (regs)->sp : (regs)->compat_sp)
>
> +extern int regs_query_register_offset(const char *name);
> +extern const char *regs_query_register_name(unsigned int offset);
> +extern bool regs_within_kernel_stack(struct pt_regs *regs, unsigned long addr);
> +extern unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs,
> + unsigned int n);
> +
> +/**
> + * regs_get_register() - get register value from its offset
> + * @regs: pt_regs from which register value is gotten
> + * @offset: offset 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)
> +{
> + u64 val = 0;
> +
> + WARN_ON(offset & 7);
> +
> + offset >>= 3;
Here, the offset is 3-bits right shifted. So,
> + switch (offset) {
> + case 0 ... 30:
> + val = regs->regs[offset];
> + break;
> + case offsetof(struct pt_regs, sp):
here should be shifted too, as
case offsetof(struct pt_regs, sp) >> 3:
> + val = regs->sp;
> + break;
> + case offsetof(struct pt_regs, pc):
and here,
> + val = regs->pc;
> + break;
> + case offsetof(struct pt_regs, pstate):
and here.
thanks,
Li Bin
> + val = regs->pstate;
> + break;
> + default:
> + val = 0;
> + }
> +
> + return val;
> +}
> +
> +/* Valid only for Kernel mode traps. */
> +static inline unsigned long kernel_stack_pointer(struct pt_regs *regs)
> +{
> + return regs->sp;
> +}
> +
> static inline unsigned long regs_return_value(struct pt_regs *regs)
> {
> return regs->regs[0];
> @@ -156,7 +208,7 @@ static inline unsigned long regs_return_value(struct pt_regs *regs)
> struct task_struct;
> int valid_user_regs(struct user_pt_regs *regs, struct task_struct *task);
>
> -#define instruction_pointer(regs) ((unsigned long)(regs)->pc)
> +#define instruction_pointer(regs) ((regs)->pc)
>
> extern unsigned long profile_pc(struct pt_regs *regs);
>
> diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c
> index 3f6cd5c..2c88c33 100644
> --- a/arch/arm64/kernel/ptrace.c
> +++ b/arch/arm64/kernel/ptrace.c
> @@ -48,6 +48,124 @@
> #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, r)}
> +#define REG_OFFSET_END {.name = NULL, .offset = 0}
> +#define GPR_OFFSET_NAME(r) \
> + {.name = "x" #r, .offset = offsetof(struct pt_regs, regs[r])}
> +
> +static const struct pt_regs_offset regoffset_table[] = {
> + GPR_OFFSET_NAME(0),
> + GPR_OFFSET_NAME(1),
> + GPR_OFFSET_NAME(2),
> + GPR_OFFSET_NAME(3),
> + GPR_OFFSET_NAME(4),
> + GPR_OFFSET_NAME(5),
> + GPR_OFFSET_NAME(6),
> + GPR_OFFSET_NAME(7),
> + GPR_OFFSET_NAME(8),
> + GPR_OFFSET_NAME(9),
> + GPR_OFFSET_NAME(10),
> + GPR_OFFSET_NAME(11),
> + GPR_OFFSET_NAME(12),
> + GPR_OFFSET_NAME(13),
> + GPR_OFFSET_NAME(14),
> + GPR_OFFSET_NAME(15),
> + GPR_OFFSET_NAME(16),
> + GPR_OFFSET_NAME(17),
> + GPR_OFFSET_NAME(18),
> + GPR_OFFSET_NAME(19),
> + GPR_OFFSET_NAME(20),
> + GPR_OFFSET_NAME(21),
> + GPR_OFFSET_NAME(22),
> + GPR_OFFSET_NAME(23),
> + GPR_OFFSET_NAME(24),
> + GPR_OFFSET_NAME(25),
> + GPR_OFFSET_NAME(26),
> + GPR_OFFSET_NAME(27),
> + GPR_OFFSET_NAME(28),
> + GPR_OFFSET_NAME(29),
> + GPR_OFFSET_NAME(30),
> + {.name = "lr", .offset = offsetof(struct pt_regs, regs[30])},
> + REG_OFFSET_NAME(sp),
> + REG_OFFSET_NAME(pc),
> + REG_OFFSET_NAME(pstate),
> + 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))) ||
> + on_irq_stack(addr, raw_smp_processor_id());
> +}
> +
> +/**
> + * 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.
>
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