Add following APIs for accessing registers and stack entries from pt_regs. - query_register_offset(const char *name) Query the offset of "name" register. - query_register_name(unsigned offset) Query the name of register by its offset. - get_register(struct pt_regs *regs, unsigned offset) Get the value of a register by its offset. - within_kernel_stack(struct pt_regs *regs, unsigned long addr) Check the address is in the kernel stack. - get_kernel_stack_nth(struct pt_regs *reg, unsigned nth) Get Nth entry of the kernel stack. (N >= 0) - get_argument_nth(struct pt_regs *reg, unsigned nth) Get Nth argument at function call. (N >= 0) Signed-off-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx> Cc: Steven Rostedt <rostedt@xxxxxxxxxxx> Cc: Ananth N Mavinakayanahalli <ananth@xxxxxxxxxx> Cc: Ingo Molnar <mingo@xxxxxxx> Cc: Frederic Weisbecker <fweisbec@xxxxxxxxx> Cc: Roland McGrath <roland@xxxxxxxxxx> --- arch/x86/include/asm/ptrace.h | 67 +++++++++++++++++++++++++++++++++++++++++ arch/x86/kernel/ptrace.c | 60 +++++++++++++++++++++++++++++++++++++ 2 files changed, 127 insertions(+), 0 deletions(-) diff --git a/arch/x86/include/asm/ptrace.h b/arch/x86/include/asm/ptrace.h index 0f0d908..577d625 100644 --- a/arch/x86/include/asm/ptrace.h +++ b/arch/x86/include/asm/ptrace.h @@ -7,6 +7,7 @@ #ifdef __KERNEL__ #include <asm/segment.h> +#include <asm/page_types.h> #endif #ifndef __ASSEMBLY__ @@ -216,6 +217,72 @@ static inline unsigned long user_stack_pointer(struct pt_regs *regs) return regs->sp; } +/* Query offset/name of register from its name/offset */ +extern int query_register_offset(const char *name); +extern const char *query_register_name(unsigned offset); +#define MAX_REG_OFFSET (offsetof(struct pt_regs, ss)) + +/* Get register value from its offset */ +static inline unsigned long get_register(struct pt_regs *regs, unsigned offset) +{ + if (unlikely(offset > MAX_REG_OFFSET)) + return 0; + return *(unsigned long *)((unsigned long)regs + offset); +} + +/* Check the address in the stack */ +static inline int within_kernel_stack(struct pt_regs *regs, unsigned long addr) +{ + return ((addr & ~(THREAD_SIZE - 1)) == + (kernel_stack_pointer(regs) & ~(THREAD_SIZE - 1))); +} + +/* Get Nth entry of the stack */ +static inline unsigned long get_kernel_stack_nth(struct pt_regs *regs, + unsigned n) +{ + unsigned long *addr = (unsigned long *)kernel_stack_pointer(regs); + addr += n; + if (within_kernel_stack(regs, (unsigned long)addr)) + return *addr; + else + return 0; +} + +/* Get Nth argument at function call */ +static inline unsigned long get_argument_nth(struct pt_regs *regs, unsigned n) +{ +#ifdef CONFIG_X86_32 +#define NR_REGPARMS 3 + if (n < NR_REGPARMS) { + switch (n) { + case 0: return regs->ax; + case 1: return regs->dx; + case 2: return regs->cx; + } + return 0; +#else /* CONFIG_X86_64 */ +#define NR_REGPARMS 6 + if (n < NR_REGPARMS) { + switch (n) { + case 0: return regs->di; + case 1: return regs->si; + case 2: return regs->dx; + case 3: return regs->cx; + case 4: return regs->r8; + case 5: return regs->r9; + } + return 0; +#endif + } else { + /* + * The typical case: arg n is on the stack. + * (Note: stack[0] = return address, so skip it) + */ + return get_kernel_stack_nth(regs, 1 + n - NR_REGPARMS); + } +} + /* * These are defined as per linux/ptrace.h, which see. */ diff --git a/arch/x86/kernel/ptrace.c b/arch/x86/kernel/ptrace.c index 09ecbde..00eb9d7 100644 --- a/arch/x86/kernel/ptrace.c +++ b/arch/x86/kernel/ptrace.c @@ -48,6 +48,66 @@ enum x86_regset { REGSET_IOPERM32, }; +struct pt_regs_offset { + const char *name; + int offset; +}; + +#define REG_OFFSET(r) offsetof(struct pt_regs, r) +#define REG_OFFSET_NAME(r) {.name = #r, .offset = REG_OFFSET(r)} +#define REG_OFFSET_END {.name = NULL, .offset = 0} + +static const struct pt_regs_offset regoffset_table[] = { +#ifdef CONFIG_X86_64 + REG_OFFSET_NAME(r15), + REG_OFFSET_NAME(r14), + REG_OFFSET_NAME(r13), + REG_OFFSET_NAME(r12), + REG_OFFSET_NAME(r11), + REG_OFFSET_NAME(r10), + REG_OFFSET_NAME(r9), + REG_OFFSET_NAME(r8), +#endif + REG_OFFSET_NAME(bx), + REG_OFFSET_NAME(cx), + REG_OFFSET_NAME(dx), + REG_OFFSET_NAME(si), + REG_OFFSET_NAME(di), + REG_OFFSET_NAME(bp), + REG_OFFSET_NAME(ax), +#ifdef CONFIG_X86_32 + REG_OFFSET_NAME(ds), + REG_OFFSET_NAME(es), + REG_OFFSET_NAME(fs), + REG_OFFSET_NAME(gs), +#endif + REG_OFFSET_NAME(orig_ax), + REG_OFFSET_NAME(ip), + REG_OFFSET_NAME(cs), + REG_OFFSET_NAME(flags), + REG_OFFSET_NAME(sp), + REG_OFFSET_NAME(ss), + REG_OFFSET_END, +}; + +int 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; +} + +const char *query_register_name(unsigned offset) +{ + const struct pt_regs_offset *roff; + for (roff = regoffset_table; roff->name != NULL; roff++) + if (roff->offset == offset) + return roff->name; + return NULL; +} + /* * does not yet catch signals sent when the child dies. * in exit.c or in signal.c. -- Masami Hiramatsu Software Engineer Hitachi Computer Products (America), Inc. 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