* [PATCH -tip v14 05/12] x86: add pt_regs register and stack access APIs [not found] <20090813203403.31965.20973.stgit@localhost.localdomain> @ 2009-08-13 20:34 ` Masami Hiramatsu 2009-08-13 20:34 ` Masami Hiramatsu 0 siblings, 1 reply; 2+ messages in thread From: Masami Hiramatsu @ 2009-08-13 20:34 UTC (permalink / raw) To: Steven Rostedt, lkml Cc: systemtap, kvm, DLE, Masami Hiramatsu, linux-arch, Ananth N Mavinakayanahalli, Avi Kivity, Andi Kleen, Christoph Hellwig, Frank Ch. Eigler, H. Peter Anvin, Ingo Molnar, Jason Baron, Jim Keniston, K.Prasad, Lai Jiangshan, Li Zefan, PrzemysławPawełczyk, Roland McGrat h, Sam Ravnborg, Srikar Dronamraju Add following APIs for accessing registers and stack entries from pt_regs. These APIs are required by kprobes-based event tracer on ftrace. Some other debugging tools might be able to use it too. - regs_query_register_offset(const char *name) Query the offset of "name" register. - regs_query_register_name(unsigned int offset) Query the name of register by its offset. - regs_get_register(struct pt_regs *regs, unsigned int 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 int nth) Get Nth entry of the kernel stack. (N >= 0) - regs_get_argument_nth(struct pt_regs *reg, unsigned int nth) Get Nth argument at function call. (N >= 0) Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com> Reviewed-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: linux-arch@vger.kernel.org Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Avi Kivity <avi@redhat.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Frank Ch. Eigler <fche@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Jason Baron <jbaron@redhat.com> Cc: Jim Keniston <jkenisto@us.ibm.com> Cc: K.Prasad <prasad@linux.vnet.ibm.com> Cc: Lai Jiangshan <laijs@cn.fujitsu.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Przemysław Pawełczyk <przemyslaw@pawelczyk.it> Cc: Roland McGrath <roland@redhat.com> Cc: Sam Ravnborg <sam@ravnborg.org> Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Tom Zanussi <tzanussi@gmail.com> Cc: Vegard Nossum <vegard.nossum@gmail.com> --- arch/x86/include/asm/ptrace.h | 62 +++++++++++++++++++++++ arch/x86/kernel/ptrace.c | 112 +++++++++++++++++++++++++++++++++++++++++ 2 files changed, 174 insertions(+), 0 deletions(-) diff --git a/arch/x86/include/asm/ptrace.h b/arch/x86/include/asm/ptrace.h index 0f0d908..a3d49dd 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 +217,67 @@ 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 int 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 int 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 int 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; +} + +/* Get Nth argument at function call */ +extern unsigned long regs_get_argument_nth(struct pt_regs *regs, + unsigned int n); + /* * 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 916082d..d270530 100644 --- a/arch/x86/kernel/ptrace.c +++ b/arch/x86/kernel/ptrace.c @@ -52,6 +52,118 @@ 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 int offset) +{ + const struct pt_regs_offset *roff; + for (roff = regoffset_table; roff->name != NULL; roff++) + if (roff->offset == offset) + return roff->name; + return NULL; +} + +static const int arg_offs_table[] = { +#ifdef CONFIG_X86_32 + [0] = offsetof(struct pt_regs, ax), + [1] = offsetof(struct pt_regs, dx), + [2] = offsetof(struct pt_regs, cx) +#else /* CONFIG_X86_64 */ + [0] = offsetof(struct pt_regs, di), + [1] = offsetof(struct pt_regs, si), + [2] = offsetof(struct pt_regs, dx), + [3] = offsetof(struct pt_regs, cx), + [4] = offsetof(struct pt_regs, r8), + [5] = offsetof(struct pt_regs, r9) +#endif +}; + +/** + * 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. + */ +unsigned long regs_get_argument_nth(struct pt_regs *regs, unsigned int n) +{ + if (n < ARRAY_SIZE(arg_offs_table)) + return *((unsigned long *)regs + arg_offs_table[n]); + else { + /* + * The typical case: arg n is on the stack. + * (Note: stack[0] = return address, so skip it) + */ + n -= ARRAY_SIZE(arg_offs_table); + return regs_get_kernel_stack_nth(regs, 1 + n); + } +} + /* * 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 ^ permalink raw reply related [flat|nested] 2+ messages in thread
* [PATCH -tip v14 05/12] x86: add pt_regs register and stack access APIs 2009-08-13 20:34 ` [PATCH -tip v14 05/12] x86: add pt_regs register and stack access APIs Masami Hiramatsu @ 2009-08-13 20:34 ` Masami Hiramatsu 0 siblings, 0 replies; 2+ messages in thread From: Masami Hiramatsu @ 2009-08-13 20:34 UTC (permalink / raw) To: Ingo Molnar, Steven Rostedt, lkml Cc: systemtap, kvm, DLE, Masami Hiramatsu, linux-arch, Ananth N Mavinakayanahalli, Avi Kivity, Andi Kleen, Christoph Hellwig, Frank Ch. Eigler, H. Peter Anvin, Jason Baron, Jim Keniston, K.Prasad, Lai Jiangshan, Li Zefan, PrzemysławPawełczyk, Roland McGrath, Sam Ravnborg, Srikar Dronamraju, Tom Zanussi, Vegard Nossum Add following APIs for accessing registers and stack entries from pt_regs. These APIs are required by kprobes-based event tracer on ftrace. Some other debugging tools might be able to use it too. - regs_query_register_offset(const char *name) Query the offset of "name" register. - regs_query_register_name(unsigned int offset) Query the name of register by its offset. - regs_get_register(struct pt_regs *regs, unsigned int 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 int nth) Get Nth entry of the kernel stack. (N >= 0) - regs_get_argument_nth(struct pt_regs *reg, unsigned int nth) Get Nth argument at function call. (N >= 0) Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com> Reviewed-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: linux-arch@vger.kernel.org Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Avi Kivity <avi@redhat.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Frank Ch. Eigler <fche@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Jason Baron <jbaron@redhat.com> Cc: Jim Keniston <jkenisto@us.ibm.com> Cc: K.Prasad <prasad@linux.vnet.ibm.com> Cc: Lai Jiangshan <laijs@cn.fujitsu.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Przemysław Pawełczyk <przemyslaw@pawelczyk.it> Cc: Roland McGrath <roland@redhat.com> Cc: Sam Ravnborg <sam@ravnborg.org> Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Tom Zanussi <tzanussi@gmail.com> Cc: Vegard Nossum <vegard.nossum@gmail.com> --- arch/x86/include/asm/ptrace.h | 62 +++++++++++++++++++++++ arch/x86/kernel/ptrace.c | 112 +++++++++++++++++++++++++++++++++++++++++ 2 files changed, 174 insertions(+), 0 deletions(-) diff --git a/arch/x86/include/asm/ptrace.h b/arch/x86/include/asm/ptrace.h index 0f0d908..a3d49dd 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 +217,67 @@ 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 int 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 int 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 int 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; +} + +/* Get Nth argument at function call */ +extern unsigned long regs_get_argument_nth(struct pt_regs *regs, + unsigned int n); + /* * 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 916082d..d270530 100644 --- a/arch/x86/kernel/ptrace.c +++ b/arch/x86/kernel/ptrace.c @@ -52,6 +52,118 @@ 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 int offset) +{ + const struct pt_regs_offset *roff; + for (roff = regoffset_table; roff->name != NULL; roff++) + if (roff->offset == offset) + return roff->name; + return NULL; +} + +static const int arg_offs_table[] = { +#ifdef CONFIG_X86_32 + [0] = offsetof(struct pt_regs, ax), + [1] = offsetof(struct pt_regs, dx), + [2] = offsetof(struct pt_regs, cx) +#else /* CONFIG_X86_64 */ + [0] = offsetof(struct pt_regs, di), + [1] = offsetof(struct pt_regs, si), + [2] = offsetof(struct pt_regs, dx), + [3] = offsetof(struct pt_regs, cx), + [4] = offsetof(struct pt_regs, r8), + [5] = offsetof(struct pt_regs, r9) +#endif +}; + +/** + * 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. + */ +unsigned long regs_get_argument_nth(struct pt_regs *regs, unsigned int n) +{ + if (n < ARRAY_SIZE(arg_offs_table)) + return *((unsigned long *)regs + arg_offs_table[n]); + else { + /* + * The typical case: arg n is on the stack. + * (Note: stack[0] = return address, so skip it) + */ + n -= ARRAY_SIZE(arg_offs_table); + return regs_get_kernel_stack_nth(regs, 1 + n); + } +} + /* * 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 ^ permalink raw reply related [flat|nested] 2+ messages in thread
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2009-08-13 20:34 ` [PATCH -tip v14 05/12] x86: add pt_regs register and stack access APIs Masami Hiramatsu
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