Commit e513f8bf authored by Will Deacon's avatar Will Deacon Committed by Russell King

ARM: 6199/1: Add kprobe-based event tracer

This patch enables the HAVE_REGS_AND_STACK_ACCESS_API option
for ARM which is required by the kprobe events tracer. Code based
on the PowerPC port.

Cc: Jean Pihet <jpihet@mvista.com>
Tested-by: default avatarJamie Iles <jamie.iles@picochip.com>
Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent eb668c6d
......@@ -24,6 +24,7 @@ config ARM
select HAVE_KERNEL_LZMA
select HAVE_PERF_EVENTS
select PERF_USE_VMALLOC
select HAVE_REGS_AND_STACK_ACCESS_API
help
The ARM series is a line of low-power-consumption RISC chip designs
licensed by ARM Ltd and targeted at embedded applications and
......
......@@ -184,6 +184,42 @@ extern unsigned long profile_pc(struct pt_regs *regs);
#define predicate(x) ((x) & 0xf0000000)
#define PREDICATE_ALWAYS 0xe0000000
/*
* kprobe-based event tracer support
*/
#include <linux/stddef.h>
#include <linux/types.h>
#define MAX_REG_OFFSET (offsetof(struct pt_regs, ARM_ORIG_r0))
extern int regs_query_register_offset(const char *name);
extern const char *regs_query_register_name(unsigned int offset);
extern bool regs_within_kernel_stack(struct pt_regs *regs, unsigned long addr);
extern unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs,
unsigned int n);
/**
* 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);
}
/* Valid only for Kernel mode traps. */
static inline unsigned long kernel_stack_pointer(struct pt_regs *regs)
{
return regs->ARM_sp;
}
#endif /* __KERNEL__ */
#endif /* __ASSEMBLY__ */
......
......@@ -52,6 +52,102 @@
#define BREAKINST_THUMB 0xde01
#endif
struct pt_regs_offset {
const char *name;
int offset;
};
#define REG_OFFSET_NAME(r) \
{.name = #r, .offset = offsetof(struct pt_regs, ARM_##r)}
#define REG_OFFSET_END {.name = NULL, .offset = 0}
static const struct pt_regs_offset regoffset_table[] = {
REG_OFFSET_NAME(r0),
REG_OFFSET_NAME(r1),
REG_OFFSET_NAME(r2),
REG_OFFSET_NAME(r3),
REG_OFFSET_NAME(r4),
REG_OFFSET_NAME(r5),
REG_OFFSET_NAME(r6),
REG_OFFSET_NAME(r7),
REG_OFFSET_NAME(r8),
REG_OFFSET_NAME(r9),
REG_OFFSET_NAME(r10),
REG_OFFSET_NAME(fp),
REG_OFFSET_NAME(ip),
REG_OFFSET_NAME(sp),
REG_OFFSET_NAME(lr),
REG_OFFSET_NAME(pc),
REG_OFFSET_NAME(cpsr),
REG_OFFSET_NAME(ORIG_r0),
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;
}
/**
* 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.
*/
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.
*/
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;
}
/*
* this routine will get a word off of the processes privileged stack.
* the offset is how far from the base addr as stored in the THREAD.
......
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