From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 17628 invoked by alias); 6 Jul 2009 01:42:23 -0000 Received: (qmail 17616 invoked by uid 22791); 6 Jul 2009 01:42:22 -0000 X-SWARE-Spam-Status: No, hits=-2.3 required=5.0 tests=AWL,BAYES_00,J_CHICKENPOX_44,SPF_PASS X-Spam-Check-By: sourceware.org Received: from mail-ew0-f222.google.com (HELO mail-ew0-f222.google.com) (209.85.219.222) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Mon, 06 Jul 2009 01:42:14 +0000 Received: by ewy22 with SMTP id 22so4083998ewy.26 for ; Sun, 05 Jul 2009 18:42:11 -0700 (PDT) Received: by 10.210.79.3 with SMTP id c3mr4838889ebb.84.1246844531385; Sun, 05 Jul 2009 18:42:11 -0700 (PDT) Received: from nowhere (ADijon-552-1-11-157.w92-138.abo.wanadoo.fr [92.138.22.157]) by mx.google.com with ESMTPS id 7sm10331505eyg.47.2009.07.05.18.42.08 (version=SSLv3 cipher=RC4-MD5); Sun, 05 Jul 2009 18:42:09 -0700 (PDT) Received: by nowhere (nbSMTP-1.00) for uid 1000 (using TLSv1/SSLv3 with cipher RC4-MD5 (128/128 bits)) fweisbec@gmail.com; Mon, 6 Jul 2009 03:42:09 +0200 (CEST) Date: Mon, 06 Jul 2009 01:42:00 -0000 From: Frederic Weisbecker To: Masami Hiramatsu Cc: Ingo Molnar , Steven Rostedt , lkml , systemtap , kvm , DLE , Christoph Hellwig , Ananth N Mavinakayanahalli , Roland McGrath , Srikar Dronamraju , linux-arch@vger.kernel.org Subject: Re: [PATCH -tip -v10 5/7] x86: add pt_regs register and stack access APIs Message-ID: <20090706014204.GB20897@nowhere> References: <20090701010838.32547.62843.stgit@localhost.localdomain> <20090701010911.32547.1313.stgit@localhost.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090701010911.32547.1313.stgit@localhost.localdomain> User-Agent: Mutt/1.5.18 (2008-05-17) Mailing-List: contact systemtap-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Post: List-Help: , Sender: systemtap-owner@sourceware.org X-SW-Source: 2009-q3/txt/msg00023.txt.bz2 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 > Cc: Christoph Hellwig > Cc: Steven Rostedt > Cc: Ananth N Mavinakayanahalli > Cc: Ingo Molnar > Cc: Frederic Weisbecker > Cc: Roland McGrath > Cc: Srikar Dronamraju > Cc: linux-arch@vger.kernel.org Looks good! Reviewed-by: Frederic Weisbecker 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 > +#include > #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