Commit bfe47f35 authored by Guo Ren's avatar Guo Ren Committed by Guo Ren
Browse files

csky: Implement ptrace regs and stack API 

Needed for kprobes support. Copied and adapted from Patrick's patch,
but it has been modified for csky's pt_regs.

ref:
https://lore.kernel.org/linux-riscv/1572919114-3886-2-git-send-email-vincent.chen@sifive.com/raw



Signed-off-by: default avatarGuo Ren <ren_guo@c-sky.com>
Cc: Patrick Staehlin <me@packi.ch>
parent 12879bda

arch/csky/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -48,6 +48,7 @@ config CSKY 
	select HAVE_PERF_REGS

	select HAVE_PERF_USER_STACK_DUMP

	select HAVE_DMA_CONTIGUOUS

	select HAVE_REGS_AND_STACK_ACCESS_API

	select HAVE_STACKPROTECTOR

	select HAVE_SYSCALL_TRACEPOINTS

	select MAY_HAVE_SPARSE_IRQ

arch/csky/include/asm/ptrace.h

+41 −0
Original line number Diff line number Diff line
@@ -7,6 +7,7 @@ 
#include <uapi/asm/ptrace.h>

#include <asm/traps.h>

#include <linux/types.h>

#include <linux/compiler.h>



#ifndef __ASSEMBLY__
@@ -22,6 +23,18 @@ 
#define instruction_pointer(regs) ((regs)->pc)

#define profile_pc(regs) instruction_pointer(regs)



static inline void instruction_pointer_set(struct pt_regs *regs,

					   unsigned long val)

{

	regs->pc = val;

}



#if defined(__CSKYABIV2__)

#define MAX_REG_OFFSET offsetof(struct pt_regs, dcsr)

#else

#define MAX_REG_OFFSET offsetof(struct pt_regs, regs[9])

#endif



static inline bool in_syscall(struct pt_regs const *regs)

{

	return ((regs->sr >> 16) & 0xff) == VEC_TRAP0;
@@ -37,5 +50,33 @@ static inline unsigned long regs_return_value(struct pt_regs *regs) 
	return regs->a0;

}



/* Valid only for Kernel mode traps. */

static inline unsigned long kernel_stack_pointer(struct pt_regs *regs)

{

	return regs->usp;

}



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__ */

#endif /* __ASM_CSKY_PTRACE_H */

arch/csky/kernel/ptrace.c

+103 −0
Original line number Diff line number Diff line
@@ -193,6 +193,109 @@ const struct user_regset_view *task_user_regset_view(struct task_struct *task) 
	return &user_csky_view;

}



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(tls),

	REG_OFFSET_NAME(lr),

	REG_OFFSET_NAME(pc),

	REG_OFFSET_NAME(sr),

	REG_OFFSET_NAME(usp),

	REG_OFFSET_NAME(orig_a0),

	REG_OFFSET_NAME(a0),

	REG_OFFSET_NAME(a1),

	REG_OFFSET_NAME(a2),

	REG_OFFSET_NAME(a3),

	REG_OFFSET_NAME(regs[0]),

	REG_OFFSET_NAME(regs[1]),

	REG_OFFSET_NAME(regs[2]),

	REG_OFFSET_NAME(regs[3]),

	REG_OFFSET_NAME(regs[4]),

	REG_OFFSET_NAME(regs[5]),

	REG_OFFSET_NAME(regs[6]),

	REG_OFFSET_NAME(regs[7]),

	REG_OFFSET_NAME(regs[8]),

	REG_OFFSET_NAME(regs[9]),

#if defined(__CSKYABIV2__)

	REG_OFFSET_NAME(exregs[0]),

	REG_OFFSET_NAME(exregs[1]),

	REG_OFFSET_NAME(exregs[2]),

	REG_OFFSET_NAME(exregs[3]),

	REG_OFFSET_NAME(exregs[4]),

	REG_OFFSET_NAME(exregs[5]),

	REG_OFFSET_NAME(exregs[6]),

	REG_OFFSET_NAME(exregs[7]),

	REG_OFFSET_NAME(exregs[8]),

	REG_OFFSET_NAME(exregs[9]),

	REG_OFFSET_NAME(exregs[10]),

	REG_OFFSET_NAME(exregs[11]),

	REG_OFFSET_NAME(exregs[12]),

	REG_OFFSET_NAME(exregs[13]),

	REG_OFFSET_NAME(exregs[14]),

	REG_OFFSET_NAME(rhi),

	REG_OFFSET_NAME(rlo),

	REG_OFFSET_NAME(dcsr),

#endif

	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;

}



void ptrace_disable(struct task_struct *child)

{

	singlestep_disable(child);