On 27/04/16 19:52, David Long wrote: > From: "David A. Long" <dave.l...@linaro.org> > > Add HAVE_REGS_AND_STACK_ACCESS_API feature for arm64.
And clearly a lot more. > > Signed-off-by: David A. Long <dave.l...@linaro.org> > --- > arch/arm64/Kconfig | 1 + > arch/arm64/include/asm/ptrace.h | 33 ++++++++++- > arch/arm64/kernel/ptrace.c | 118 > ++++++++++++++++++++++++++++++++++++++++ > 3 files changed, 151 insertions(+), 1 deletion(-) > > diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig > index 4f43622..8f662fd 100644 > --- a/arch/arm64/Kconfig > +++ b/arch/arm64/Kconfig > @@ -80,6 +80,7 @@ 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..ee02637 100644 > --- a/arch/arm64/include/asm/ptrace.h > +++ b/arch/arm64/include/asm/ptrace.h > @@ -119,6 +119,8 @@ 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 +149,35 @@ 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 number of the register. Is it the offset? or the number? > + * > + * 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); So clearly it is the offset. But is 3 a valid value? I don't think so. How about something slightly more type safe: u64 val = 0; WARN_ON(offset & 7); offset >>= 3; switch (offset) { case 0 ... 30: val = regs->reg[offset]; break; case 31: val = regs->sp; break; case 32: val = regs->pc; break; case 33: val = regs->pstate; break; } return val; I'm pretty sure you could replace 31/32/33 with macros using offsetof(). The compiler may even optimize this to something similar to what you already have. Thanks, M. -- Jazz is not dead. It just smells funny...