Messages in this thread | | | Date | Mon, 29 Jun 2015 14:36:45 -0400 | From | David Long <> | Subject | Re: [PATCH v7 1/7] arm64: Add HAVE_REGS_AND_STACK_ACCESS_API feature |
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On 06/29/15 13:23, Steve Capper wrote: > On 15 June 2015 at 20:07, David Long <dave.long@linaro.org> wrote: >> From: "David A. Long" <dave.long@linaro.org> >> >> Add HAVE_REGS_AND_STACK_ACCESS_API feature for arm64. >> >> Signed-off-by: David A. Long <dave.long@linaro.org> >> --- >> arch/arm64/Kconfig | 1 + >> arch/arm64/include/asm/ptrace.h | 25 +++++++++++++ >> arch/arm64/kernel/ptrace.c | 77 +++++++++++++++++++++++++++++++++++++++++ >> 3 files changed, 103 insertions(+) >> >> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig >> index 7796af4..966091f 100644 >> --- a/arch/arm64/Kconfig >> +++ b/arch/arm64/Kconfig >> @@ -68,6 +68,7 @@ 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 d6dd9fd..8f440e9 100644 >> --- a/arch/arm64/include/asm/ptrace.h >> +++ b/arch/arm64/include/asm/ptrace.h >> @@ -118,6 +118,8 @@ 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 >> @@ -146,6 +148,29 @@ 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); > > Why not: > return regs->regs[offset]; >
This would not be correct. The offset is a byte offset and your code would index eight times that amount into the structure. The offset needs to remain a byte offset so architecture-independent code does not need to know the architecture-specific layout of the structure.
>> +} >> + >> +/* 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]; >> diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c >> index d882b83..f6199a5 100644 >> --- a/arch/arm64/kernel/ptrace.c >> +++ b/arch/arm64/kernel/ptrace.c >> @@ -48,6 +48,83 @@ >> #define CREATE_TRACE_POINTS >> #include <trace/events/syscalls.h> >> >> +#define ARM_pstate pstate >> +#define ARM_pc pc >> +#define ARM_sp sp >> +#define ARM_x30 regs[30] >> +#define ARM_x29 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_x17 regs[17] >> +#define ARM_x16 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 REG_OFFSET_NAME(r) \ >> + {.name = #r, .offset = offsetof(struct pt_regs, ARM_##r)} >> +#define REG_OFFSET_END {.name = NULL, .offset = 0} >> + >> +const struct pt_regs_offset regs_offset_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(x16), >> + REG_OFFSET_NAME(x17), >> + 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(x29), >> + REG_OFFSET_NAME(x30), >> + REG_OFFSET_NAME(sp), >> + REG_OFFSET_NAME(pc), >> + REG_OFFSET_NAME(pstate), >> + REG_OFFSET_END, >> +}; >> + >> /* >> * TODO: does not yet catch signals sent when the child dies. >> * in exit.c or in signal.c. >> -- >> 1.8.1.2 >>
Thanks, -dl
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