| Message ID | 20090701010911.32547.1313.stgit@localhost.localdomain (mailing list archive) |
|---|---|
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On Tue, Jun 30, 2009 at 09:09:11PM -0400, Masami Hiramatsu wrote: > Add following APIs for accessing registers and stack entries from pt_regs. > > - regs_query_register_offset(const char *name) > Query the offset of "name" register. > > - regs_query_register_name(unsigned offset) > Query the name of register by its offset. > > - regs_get_register(struct pt_regs *regs, unsigned offset) > Get the value of a register by its offset. > > - regs_within_kernel_stack(struct pt_regs *regs, unsigned long addr) > Check the address is in the kernel stack. > > - regs_get_kernel_stack_nth(struct pt_regs *reg, unsigned nth) > Get Nth entry of the kernel stack. (N >= 0) > > - regs_get_argument_nth(struct pt_regs *reg, unsigned nth) > Get Nth argument at function call. (N >= 0) > > Changes from v9: > -Fix a typo in a comment. > > Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com> > Cc: Christoph Hellwig <hch@infradead.org> > Cc: Steven Rostedt <rostedt@goodmis.org> > Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> > Cc: Ingo Molnar <mingo@elte.hu> > Cc: Frederic Weisbecker <fweisbec@gmail.com> > Cc: Roland McGrath <roland@redhat.com> > Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> > Cc: linux-arch@vger.kernel.org Looks good! Reviewed-by: Frederic Weisbecker <fweisbec@gmail.com> Frederic. > --- > > arch/x86/include/asm/ptrace.h | 122 +++++++++++++++++++++++++++++++++++++++++ > arch/x86/kernel/ptrace.c | 73 +++++++++++++++++++++++++ > 2 files changed, 195 insertions(+), 0 deletions(-) > > diff --git a/arch/x86/include/asm/ptrace.h b/arch/x86/include/asm/ptrace.h > index 0f0d908..d5e3b3b 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 +217,127 @@ 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 regs_query_register_offset(const char *name); > +extern const char *regs_query_register_name(unsigned offset); > +#define MAX_REG_OFFSET (offsetof(struct pt_regs, ss)) > + > +/** > + * 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 > + * is @offset. 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 unsigned long regs_get_register(struct pt_regs *regs, > + unsigned offset) > +{ > + if (unlikely(offset > MAX_REG_OFFSET)) > + return 0; > + return *(unsigned long *)((unsigned long)regs + offset); > +} > + > +/** > + * 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_kenel_stack() checks @addr is within the kernel stack page(s). > + * If @addr is within the kernel stack, it returns true. If not, returns false. > + */ > +static inline int 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 specifined by @regs. If the @n th entry is NOT in the kernel stack, > + * this returns 0. > + */ > +static inline unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs, > + unsigned 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; > +} > + > +/** > + * regs_get_argument_nth() - get Nth argument at function call > + * @regs: pt_regs which contains registers at function entry. > + * @n: argument number. > + * > + * regs_get_argument_nth() returns @n th argument of a function call. > + * Since usually the kernel stack will be changed right after function entry, > + * you must use this at function entry. If the @n th entry is NOT in the > + * kernel stack or pt_regs, this returns 0. > + */ > +#ifdef CONFIG_X86_32 > +#define NR_REGPARMS 3 > +static inline unsigned long regs_get_argument_nth(struct pt_regs *regs, > + unsigned n) > +{ > + if (n < NR_REGPARMS) { > + switch (n) { > + case 0: > + return regs->ax; > + case 1: > + return regs->dx; > + case 2: > + return regs->cx; > + } > + return 0; > + } else { > + /* > + * The typical case: arg n is on the stack. > + * (Note: stack[0] = return address, so skip it) > + */ > + return regs_get_kernel_stack_nth(regs, 1 + n - NR_REGPARMS); > + } > +} > +#else /* CONFIG_X86_64 */ > +#define NR_REGPARMS 6 > +static inline unsigned long regs_get_argument_nth(struct pt_regs *regs, > + unsigned n) > +{ > + 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; > + } else { > + /* > + * The typical case: arg n is on the stack. > + * (Note: stack[0] = return address, so skip it) > + */ > + return regs_get_kernel_stack_nth(regs, 1 + n - NR_REGPARMS); > + } > +} > +#endif > + > /* > * 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 b457f78..2944d3a 100644 > --- a/arch/x86/kernel/ptrace.c > +++ b/arch/x86/kernel/ptrace.c > @@ -49,6 +49,79 @@ enum x86_regset { > REGSET_IOPERM32, > }; > > +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} > + > +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, > +}; > + > +/** > + * 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 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. > Software Solutions Division > > e-mail: mhiramat@redhat.com -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Masami Hiramatsu <mhiramat@redhat.com> writes: > Add following APIs for accessing registers and stack entries from pt_regs. You forgot to state who calls these functions/why are they added? Who only has strings for registers? I can see the point of having a function for nth argument though, that's useful. > +static inline unsigned long regs_get_argument_nth(struct pt_regs *regs, > + unsigned n) > +{ > + if (n < NR_REGPARMS) { > + switch (n) { > + case 0: > + return regs->ax; > + case 1: > + return regs->dx; > + case 2: > + return regs->cx; [....] That could be done shorter with a offsetof table. > + 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; and that too. -Andi
Andi Kleen wrote: > Masami Hiramatsu <mhiramat@redhat.com> writes: > >> Add following APIs for accessing registers and stack entries from pt_regs. > > You forgot to state who calls these functions/why are they added? > Who only has strings for registers? Oh, yes. This patch is needed for kprobes based event tracer on ftrace. Some other debugging tools might be able to use it. > I can see the point of having a function for nth argument though, > that's useful. > >> +static inline unsigned long regs_get_argument_nth(struct pt_regs *regs, >> + unsigned n) >> +{ >> + if (n < NR_REGPARMS) { >> + switch (n) { >> + case 0: >> + return regs->ax; >> + case 1: >> + return regs->dx; >> + case 2: >> + return regs->cx; > > > [....] > > That could be done shorter with a offsetof table. > >> + 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; > > and that too. I'm not so sure about your idea. Would you mean below code? int offs_table[NR_REGPARMS] = { [0] = offsetof(struct pt_regs, di), ... }; if (n < NR_REGPARMS) return *((unsigned long *)regs + offs_table[n]); Thank you,
On Mon, Jul 06, 2009 at 03:28:02PM -0400, Masami Hiramatsu wrote: > I'm not so sure about your idea. > Would you mean below code? > > int offs_table[NR_REGPARMS] = { not REGPARMS of course > [0] = offsetof(struct pt_regs, di), > ... > }; > if (n < NR_REGPARMS) > return *((unsigned long *)regs + offs_table[n]); Yes. -Andi
diff --git a/arch/x86/include/asm/ptrace.h b/arch/x86/include/asm/ptrace.h index 0f0d908..d5e3b3b 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 +217,127 @@ 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 regs_query_register_offset(const char *name); +extern const char *regs_query_register_name(unsigned offset); +#define MAX_REG_OFFSET (offsetof(struct pt_regs, ss)) + +/** + * 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 + * is @offset. 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 unsigned long regs_get_register(struct pt_regs *regs, + unsigned offset) +{ + if (unlikely(offset > MAX_REG_OFFSET)) + return 0; + return *(unsigned long *)((unsigned long)regs + offset); +} + +/** + * 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_kenel_stack() checks @addr is within the kernel stack page(s). + * If @addr is within the kernel stack, it returns true. If not, returns false. + */ +static inline int 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 specifined by @regs. If the @n th entry is NOT in the kernel stack, + * this returns 0. + */ +static inline unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs, + unsigned 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; +} + +/** + * regs_get_argument_nth() - get Nth argument at function call + * @regs: pt_regs which contains registers at function entry. + * @n: argument number. + * + * regs_get_argument_nth() returns @n th argument of a function call. + * Since usually the kernel stack will be changed right after function entry, + * you must use this at function entry. If the @n th entry is NOT in the + * kernel stack or pt_regs, this returns 0. + */ +#ifdef CONFIG_X86_32 +#define NR_REGPARMS 3 +static inline unsigned long regs_get_argument_nth(struct pt_regs *regs, + unsigned n) +{ + if (n < NR_REGPARMS) { + switch (n) { + case 0: + return regs->ax; + case 1: + return regs->dx; + case 2: + return regs->cx; + } + return 0; + } else { + /* + * The typical case: arg n is on the stack. + * (Note: stack[0] = return address, so skip it) + */ + return regs_get_kernel_stack_nth(regs, 1 + n - NR_REGPARMS); + } +} +#else /* CONFIG_X86_64 */ +#define NR_REGPARMS 6 +static inline unsigned long regs_get_argument_nth(struct pt_regs *regs, + unsigned n) +{ + 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; + } else { + /* + * The typical case: arg n is on the stack. + * (Note: stack[0] = return address, so skip it) + */ + return regs_get_kernel_stack_nth(regs, 1 + n - NR_REGPARMS); + } +} +#endif + /* * 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 b457f78..2944d3a 100644 --- a/arch/x86/kernel/ptrace.c +++ b/arch/x86/kernel/ptrace.c @@ -49,6 +49,79 @@ enum x86_regset { REGSET_IOPERM32, }; +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} + +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, +}; + +/** + * 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 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.
Add following APIs for accessing registers and stack entries from pt_regs. - regs_query_register_offset(const char *name) Query the offset of "name" register. - regs_query_register_name(unsigned offset) Query the name of register by its offset. - regs_get_register(struct pt_regs *regs, unsigned offset) Get the value of a register by its offset. - regs_within_kernel_stack(struct pt_regs *regs, unsigned long addr) Check the address is in the kernel stack. - regs_get_kernel_stack_nth(struct pt_regs *reg, unsigned nth) Get Nth entry of the kernel stack. (N >= 0) - regs_get_argument_nth(struct pt_regs *reg, unsigned nth) Get Nth argument at function call. (N >= 0) Changes from v9: -Fix a typo in a comment. Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Roland McGrath <roland@redhat.com> Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Cc: linux-arch@vger.kernel.org --- arch/x86/include/asm/ptrace.h | 122 +++++++++++++++++++++++++++++++++++++++++ arch/x86/kernel/ptrace.c | 73 +++++++++++++++++++++++++ 2 files changed, 195 insertions(+), 0 deletions(-)