Commit 2225a122 authored by Suresh Siddha's avatar Suresh Siddha Committed by H. Peter Anvin
Browse files

ptrace: Add support for generic PTRACE_GETREGSET/PTRACE_SETREGSET 



Generic support for PTRACE_GETREGSET/PTRACE_SETREGSET commands which
export the regsets supported by each architecture using the correponding
NT_* types. These NT_* types are already part of the userland ABI, used
in representing the architecture specific register sets as different NOTES
in an ELF core file.

'addr' parameter for the ptrace system call encode the REGSET type (using
the corresppnding NT_* type) and the 'data' parameter points to the
struct iovec having the user buffer and the length of that buffer.

	struct iovec iov = { buf, len};
	ret = ptrace(PTRACE_GETREGSET/PTRACE_SETREGSET, pid, NT_XXX_TYPE, &iov);

On successful completion, iov.len will be updated by the kernel specifying
how much the kernel has written/read to/from the user's iov.buf.

x86 extended state registers are primarily exported using this interface.

Signed-off-by: default avatarSuresh Siddha <suresh.b.siddha@intel.com>
LKML-Reference: <20100211195614.886724710@sbs-t61.sc.intel.com>
Acked-by: default avatarHongjiu Lu <hjl.tools@gmail.com>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: default avatarH. Peter Anvin <hpa@zytor.com>
parent 5b3efd50

include/linux/elf.h

+5 −1
Original line number Diff line number Diff line
@@ -349,7 +349,11 @@ typedef struct elf64_shdr { 
#define ELF_OSABI ELFOSABI_NONE

#endif



/* Notes used in ET_CORE */

/*

 * Notes used in ET_CORE. Architectures export some of the arch register sets

 * using the corresponding note types via the PTRACE_GETREGSET and

 * PTRACE_SETREGSET requests.

 */

#define NT_PRSTATUS	1

#define NT_PRFPREG	2

#define NT_PRPSINFO	3

include/linux/ptrace.h

+15 −0
Original line number Diff line number Diff line
@@ -27,6 +27,21 @@ 
#define PTRACE_GETSIGINFO	0x4202

#define PTRACE_SETSIGINFO	0x4203



/*

 * Generic ptrace interface that exports the architecture specific regsets

 * using the corresponding NT_* types (which are also used in the core dump).

 *

 * This interface usage is as follows:

 *	struct iovec iov = { buf, len};

 *

 *	ret = ptrace(PTRACE_GETREGSET/PTRACE_SETREGSET, pid, NT_XXX_TYPE, &iov);

 *

 * On the successful completion, iov.len will be updated by the kernel,

 * specifying how much the kernel has written/read to/from the user's iov.buf.

 */

#define PTRACE_GETREGSET	0x4204

#define PTRACE_SETREGSET	0x4205



/* options set using PTRACE_SETOPTIONS */

#define PTRACE_O_TRACESYSGOOD	0x00000001

#define PTRACE_O_TRACEFORK	0x00000002

kernel/ptrace.c

+88 −0
Original line number Diff line number Diff line
@@ -22,6 +22,7 @@ 
#include <linux/pid_namespace.h>

#include <linux/syscalls.h>

#include <linux/uaccess.h>

#include <linux/regset.h>





/*
@@ -511,6 +512,47 @@ static int ptrace_resume(struct task_struct *child, long request, long data) 
	return 0;

}



#ifdef CONFIG_HAVE_ARCH_TRACEHOOK



static const struct user_regset *

find_regset(const struct user_regset_view *view, unsigned int type)

{

	const struct user_regset *regset;

	int n;



	for (n = 0; n < view->n; ++n) {

		regset = view->regsets + n;

		if (regset->core_note_type == type)

			return regset;

	}



	return NULL;

}



static int ptrace_regset(struct task_struct *task, int req, unsigned int type,

			 struct iovec *kiov)

{

	const struct user_regset_view *view = task_user_regset_view(task);

	const struct user_regset *regset = find_regset(view, type);

	int regset_no;



	if (!regset || (kiov->iov_len % regset->size) != 0)

		return -EIO;



	regset_no = regset - view->regsets;

	kiov->iov_len = min(kiov->iov_len,

			    (__kernel_size_t) (regset->n * regset->size));



	if (req == PTRACE_GETREGSET)

		return copy_regset_to_user(task, view, regset_no, 0,

					   kiov->iov_len, kiov->iov_base);

	else

		return copy_regset_from_user(task, view, regset_no, 0,

					     kiov->iov_len, kiov->iov_base);

}



#endif



int ptrace_request(struct task_struct *child, long request,

		   long addr, long data)

{
@@ -573,6 +615,26 @@ int ptrace_request(struct task_struct *child, long request, 
			return 0;

		return ptrace_resume(child, request, SIGKILL);



#ifdef CONFIG_HAVE_ARCH_TRACEHOOK

	case PTRACE_GETREGSET:

	case PTRACE_SETREGSET:

	{

		struct iovec kiov;

		struct iovec __user *uiov = (struct iovec __user *) data;



		if (!access_ok(VERIFY_WRITE, uiov, sizeof(*uiov)))

			return -EFAULT;



		if (__get_user(kiov.iov_base, &uiov->iov_base) ||

		    __get_user(kiov.iov_len, &uiov->iov_len))

			return -EFAULT;



		ret = ptrace_regset(child, request, addr, &kiov);

		if (!ret)

			ret = __put_user(kiov.iov_len, &uiov->iov_len);

		break;

	}

#endif

	default:

		break;

	}
@@ -711,6 +773,32 @@ int compat_ptrace_request(struct task_struct *child, compat_long_t request, 
		else

			ret = ptrace_setsiginfo(child, &siginfo);

		break;

#ifdef CONFIG_HAVE_ARCH_TRACEHOOK

	case PTRACE_GETREGSET:

	case PTRACE_SETREGSET:

	{

		struct iovec kiov;

		struct compat_iovec __user *uiov =

			(struct compat_iovec __user *) datap;

		compat_uptr_t ptr;

		compat_size_t len;



		if (!access_ok(VERIFY_WRITE, uiov, sizeof(*uiov)))

			return -EFAULT;



		if (__get_user(ptr, &uiov->iov_base) ||

		    __get_user(len, &uiov->iov_len))

			return -EFAULT;



		kiov.iov_base = compat_ptr(ptr);

		kiov.iov_len = len;



		ret = ptrace_regset(child, request, addr, &kiov);

		if (!ret)

			ret = __put_user(kiov.iov_len, &uiov->iov_len);

		break;

	}

#endif



	default:

		ret = ptrace_request(child, request, addr, data);

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