Commit 7ce8716e authored by Michael Jeanson's avatar Michael Jeanson Committed by Stafford Horne
Browse files

openrisc: Add HAVE_REGS_AND_STACK_ACCESS_API support 



Support for HAVE_REGS_AND_STACK_ACCESS_API needed for restartable
sequences.

The implementation has been copied from riscv and tested with the
restartable sequences self tests.

Note, pt-regs members are 'long' on openrisc which require casts for the
api, someday we should try to update these to be 'unsigned long' as
that's what they really are.

Signed-off-by: default avatarMichael Jeanson <mjeanson@efficios.com>
[stafford: Updated commit message]
Signed-off-by: default avatarStafford Horne <shorne@gmail.com>
parent 134502ab

arch/openrisc/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -27,6 +27,7 @@ config OPENRISC 
	select HAVE_PCI

	select HAVE_UID16

	select HAVE_PAGE_SIZE_8KB

	select HAVE_REGS_AND_STACK_ACCESS_API

	select GENERIC_ATOMIC64

	select GENERIC_CLOCKEVENTS_BROADCAST

	select GENERIC_SMP_IDLE_THREAD

arch/openrisc/include/asm/ptrace.h

+72 −1
Original line number Diff line number Diff line
@@ -17,6 +17,7 @@ 


#include <asm/spr_defs.h>

#include <uapi/asm/ptrace.h>

#include <linux/compiler.h>



/*

 * Make kernel PTrace/register structures opaque to userspace... userspace can
@@ -42,6 +43,36 @@ struct pt_regs { 
			/* Named registers */

			long  sr;	/* Stored in place of r0 */

			long  sp;	/* r1 */

			long  gpr2;

			long  gpr3;

			long  gpr4;

			long  gpr5;

			long  gpr6;

			long  gpr7;

			long  gpr8;

			long  gpr9;

			long  gpr10;

			long  gpr11;

			long  gpr12;

			long  gpr13;

			long  gpr14;

			long  gpr15;

			long  gpr16;

			long  gpr17;

			long  gpr18;

			long  gpr19;

			long  gpr20;

			long  gpr21;

			long  gpr22;

			long  gpr23;

			long  gpr24;

			long  gpr25;

			long  gpr26;

			long  gpr27;

			long  gpr28;

			long  gpr29;

			long  gpr30;

			long  gpr31;

		};

		struct {

			/* Old style */
@@ -66,16 +97,56 @@ struct pt_regs { 
/* TODO: Rename this to REDZONE because that's what it is */

#define STACK_FRAME_OVERHEAD  128  /* size of minimum stack frame */



#define instruction_pointer(regs)	((regs)->pc)

#define MAX_REG_OFFSET offsetof(struct pt_regs, orig_gpr11)



/* Helpers for working with the instruction pointer */

static inline unsigned long instruction_pointer(struct pt_regs *regs)

{

	return (unsigned long)regs->pc;

}

static inline void instruction_pointer_set(struct pt_regs *regs,

					   unsigned long val)

{

	regs->pc = val;

}



#define user_mode(regs)			(((regs)->sr & SPR_SR_SM) == 0)

#define user_stack_pointer(regs)	((unsigned long)(regs)->sp)

#define profile_pc(regs)		instruction_pointer(regs)



/* Valid only for Kernel mode traps. */

static inline unsigned long kernel_stack_pointer(struct pt_regs *regs)

{

	return (unsigned long)regs->sp;

}



static inline long regs_return_value(struct pt_regs *regs)

{

	return regs->gpr[11];

}



extern int regs_query_register_offset(const char *name);

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 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);

}



#endif /* __ASSEMBLY__ */



/*

arch/openrisc/kernel/ptrace.c

+96 −0
Original line number Diff line number Diff line
@@ -160,6 +160,102 @@ const struct user_regset_view *task_user_regset_view(struct task_struct *task) 
 * in exit.c or in signal.c.

 */



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[] = {

	REG_OFFSET_NAME(sr),

	REG_OFFSET_NAME(sp),

	REG_OFFSET_NAME(gpr2),

	REG_OFFSET_NAME(gpr3),

	REG_OFFSET_NAME(gpr4),

	REG_OFFSET_NAME(gpr5),

	REG_OFFSET_NAME(gpr6),

	REG_OFFSET_NAME(gpr7),

	REG_OFFSET_NAME(gpr8),

	REG_OFFSET_NAME(gpr9),

	REG_OFFSET_NAME(gpr10),

	REG_OFFSET_NAME(gpr11),

	REG_OFFSET_NAME(gpr12),

	REG_OFFSET_NAME(gpr13),

	REG_OFFSET_NAME(gpr14),

	REG_OFFSET_NAME(gpr15),

	REG_OFFSET_NAME(gpr16),

	REG_OFFSET_NAME(gpr17),

	REG_OFFSET_NAME(gpr18),

	REG_OFFSET_NAME(gpr19),

	REG_OFFSET_NAME(gpr20),

	REG_OFFSET_NAME(gpr21),

	REG_OFFSET_NAME(gpr22),

	REG_OFFSET_NAME(gpr23),

	REG_OFFSET_NAME(gpr24),

	REG_OFFSET_NAME(gpr25),

	REG_OFFSET_NAME(gpr26),

	REG_OFFSET_NAME(gpr27),

	REG_OFFSET_NAME(gpr28),

	REG_OFFSET_NAME(gpr29),

	REG_OFFSET_NAME(gpr30),

	REG_OFFSET_NAME(gpr31),

	REG_OFFSET_NAME(pc),

	REG_OFFSET_NAME(orig_gpr11),

	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_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 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;

}



/*

 * Called by kernel/ptrace.c when detaching..