powerpc: Add kprobe-based event tracer

This patch ports the kprobe-based event tracer to powerpc. This patch
is based on x86 port. This brings powerpc on par with x86.

Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Acked-by: Masami Hiramatsu <mhiramat@redhat.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
master
Mahesh Salgaonkar 13 years ago committed by Benjamin Herrenschmidt
parent a32aaf1451
commit 359e4284a3
  1. 1
      arch/powerpc/Kconfig
  2. 64
      arch/powerpc/include/asm/ptrace.h
  3. 103
      arch/powerpc/kernel/ptrace.c

@ -140,6 +140,7 @@ config PPC
select HAVE_SYSCALL_WRAPPERS if PPC64
select GENERIC_ATOMIC64 if PPC32
select HAVE_PERF_EVENTS
select HAVE_REGS_AND_STACK_ACCESS_API
config EARLY_PRINTK
bool

@ -89,6 +89,7 @@ struct pt_regs {
#define instruction_pointer(regs) ((regs)->nip)
#define user_stack_pointer(regs) ((regs)->gpr[1])
#define kernel_stack_pointer(regs) ((regs)->gpr[1])
#define regs_return_value(regs) ((regs)->gpr[3])
#ifdef CONFIG_SMP
@ -141,6 +142,69 @@ do { \
#define arch_has_block_step() (!cpu_has_feature(CPU_FTR_601))
#define ARCH_HAS_USER_SINGLE_STEP_INFO
/*
* kprobe-based event tracer support
*/
#include <linux/stddef.h>
#include <linux/thread_info.h>
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, dsisr))
/**
* 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.
* 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_kernel_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 bool 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 specified 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;
}
#endif /* __ASSEMBLY__ */
#endif /* __KERNEL__ */

@ -38,6 +38,109 @@
#include <asm/pgtable.h>
#include <asm/system.h>
/*
* The parameter save area on the stack is used to store arguments being passed
* to callee function and is located at fixed offset from stack pointer.
*/
#ifdef CONFIG_PPC32
#define PARAMETER_SAVE_AREA_OFFSET 24 /* bytes */
#else /* CONFIG_PPC32 */
#define PARAMETER_SAVE_AREA_OFFSET 48 /* bytes */
#endif
struct pt_regs_offset {
const char *name;
int offset;
};
#define STR(s) #s /* convert to string */
#define REG_OFFSET_NAME(r) {.name = #r, .offset = offsetof(struct pt_regs, r)}
#define GPR_OFFSET_NAME(num) \
{.name = STR(gpr##num), .offset = offsetof(struct pt_regs, gpr[num])}
#define REG_OFFSET_END {.name = NULL, .offset = 0}
static const struct pt_regs_offset regoffset_table[] = {
GPR_OFFSET_NAME(0),
GPR_OFFSET_NAME(1),
GPR_OFFSET_NAME(2),
GPR_OFFSET_NAME(3),
GPR_OFFSET_NAME(4),
GPR_OFFSET_NAME(5),
GPR_OFFSET_NAME(6),
GPR_OFFSET_NAME(7),
GPR_OFFSET_NAME(8),
GPR_OFFSET_NAME(9),
GPR_OFFSET_NAME(10),
GPR_OFFSET_NAME(11),
GPR_OFFSET_NAME(12),
GPR_OFFSET_NAME(13),
GPR_OFFSET_NAME(14),
GPR_OFFSET_NAME(15),
GPR_OFFSET_NAME(16),
GPR_OFFSET_NAME(17),
GPR_OFFSET_NAME(18),
GPR_OFFSET_NAME(19),
GPR_OFFSET_NAME(20),
GPR_OFFSET_NAME(21),
GPR_OFFSET_NAME(22),
GPR_OFFSET_NAME(23),
GPR_OFFSET_NAME(24),
GPR_OFFSET_NAME(25),
GPR_OFFSET_NAME(26),
GPR_OFFSET_NAME(27),
GPR_OFFSET_NAME(28),
GPR_OFFSET_NAME(29),
GPR_OFFSET_NAME(30),
GPR_OFFSET_NAME(31),
REG_OFFSET_NAME(nip),
REG_OFFSET_NAME(msr),
REG_OFFSET_NAME(ctr),
REG_OFFSET_NAME(link),
REG_OFFSET_NAME(xer),
REG_OFFSET_NAME(ccr),
#ifdef CONFIG_PPC64
REG_OFFSET_NAME(softe),
#else
REG_OFFSET_NAME(mq),
#endif
REG_OFFSET_NAME(trap),
REG_OFFSET_NAME(dar),
REG_OFFSET_NAME(dsisr),
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;
}
/*
* does not yet catch signals sent when the child dies.
* in exit.c or in signal.c.

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