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Commit 952974ac authored by Heiko Carstens's avatar Heiko Carstens Committed by Frederic Weisbecker
Browse files

s390: Add pt_regs register and stack access API 



This API is needed for the kprobe-based event tracer.

Signed-off-by: default avatarHeiko Carstens <heiko.carstens@de.ibm.com>
Reviewed-by: default avatarMasami Hiramatsu <mhiramat@redhat.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
LKML-Reference: <20100212123840.GB27548@osiris.boeblingen.de.ibm.com>
Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
parent f850c30c

arch/s390/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -87,6 +87,7 @@ config S390 
	select HAVE_SYSCALL_TRACEPOINTS

	select HAVE_DYNAMIC_FTRACE

	select HAVE_FUNCTION_GRAPH_TRACER

	select HAVE_REGS_AND_STACK_ACCESS_API

	select HAVE_DEFAULT_NO_SPIN_MUTEXES

	select HAVE_OPROFILE

	select HAVE_KPROBES

arch/s390/include/asm/ptrace.h

+12 −1
Original line number Diff line number Diff line
@@ -492,13 +492,24 @@ struct user_regs_struct 
struct task_struct;

extern void user_enable_single_step(struct task_struct *);

extern void user_disable_single_step(struct task_struct *);

extern void show_regs(struct pt_regs * regs);



#define user_mode(regs) (((regs)->psw.mask & PSW_MASK_PSTATE) != 0)

#define instruction_pointer(regs) ((regs)->psw.addr & PSW_ADDR_INSN)

#define user_stack_pointer(regs)((regs)->gprs[15])

#define regs_return_value(regs)((regs)->gprs[2])

#define profile_pc(regs) instruction_pointer(regs)

extern void show_regs(struct pt_regs * regs);



int regs_query_register_offset(const char *name);

const char *regs_query_register_name(unsigned int offset);

unsigned long regs_get_register(struct pt_regs *regs, unsigned int offset);

unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs, unsigned int n);



static inline unsigned long kernel_stack_pointer(struct pt_regs *regs)

{

	return regs->gprs[15] & PSW_ADDR_INSN;

}



#endif /* __KERNEL__ */

#endif /* __ASSEMBLY__ */

arch/s390/kernel/ptrace.c

+58 −0
Original line number Diff line number Diff line
@@ -984,3 +984,61 @@ const struct user_regset_view *task_user_regset_view(struct task_struct *task) 
#endif

	return &user_s390_view;

}



static const char *gpr_names[NUM_GPRS] = {

	"r0", "r1",  "r2",  "r3",  "r4",  "r5",  "r6",  "r7",

	"r8", "r9", "r10", "r11", "r12", "r13", "r14", "r15",

};



unsigned long regs_get_register(struct pt_regs *regs, unsigned int offset)

{

	if (offset >= NUM_GPRS)

		return 0;

	return regs->gprs[offset];

}



int regs_query_register_offset(const char *name)

{

	unsigned long offset;



	if (!name || *name != 'r')

		return -EINVAL;

	if (strict_strtoul(name + 1, 10, &offset))

		return -EINVAL;

	if (offset >= NUM_GPRS)

		return -EINVAL;

	return offset;

}



const char *regs_query_register_name(unsigned int offset)

{

	if (offset >= NUM_GPRS)

		return NULL;

	return gpr_names[offset];

}



static int regs_within_kernel_stack(struct pt_regs *regs, unsigned long addr)

{

	unsigned long ksp = kernel_stack_pointer(regs);



	return (addr & ~(THREAD_SIZE - 1)) == (ksp & ~(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.

 */

unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs, unsigned int n)

{

	unsigned long addr;



	addr = kernel_stack_pointer(regs) + n * sizeof(long);

	if (!regs_within_kernel_stack(regs, addr))

		return 0;

	return *(unsigned long *)addr;

}