Commit cb67e161 authored by Chris Metcalf's avatar Chris Metcalf
Browse files

arch/tile: provide PT_FLAGS_COMPAT value in pt_regs 



This flag is set for ptrace GETREGS or PEEKUSER for processes
that are COMPAT, i.e. 32-bit.  This allows things like strace
to easily discover what personality to use, for example.

Acked-by: default avatarOleg Nesterov <oleg@redhat.com>
Signed-off-by: default avatarChris Metcalf <cmetcalf@tilera.com>
parent 17a26354

arch/tile/include/uapi/asm/ptrace.h

+6 −0
Original line number Diff line number Diff line
@@ -84,5 +84,11 @@ struct pt_regs { 
#define PTRACE_O_TRACEMIGRATE	0x00010000

#define PTRACE_EVENT_MIGRATE	16



/*

 * Flag bits in pt_regs.flags that are part of the ptrace API.

 * We start our numbering higher up to avoid confusion with the

 * non-ABI kernel-internal values that use the low 16 bits.

 */

#define PT_FLAGS_COMPAT		0x10000  /* process is an -m32 compat process */



#endif /* _UAPI_ASM_TILE_PTRACE_H */

arch/tile/kernel/ptrace.c

+40 −17
Original line number Diff line number Diff line
@@ -45,6 +45,41 @@ void ptrace_disable(struct task_struct *child) 
	clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);

}



/*

 * Get registers from task and ready the result for userspace.

 * Note that we localize the API issues to getregs() and putregs() at

 * some cost in performance, e.g. we need a full pt_regs copy for

 * PEEKUSR, and two copies for POKEUSR.  But in general we expect

 * GETREGS/PUTREGS to be the API of choice anyway.

 */

static char *getregs(struct task_struct *child, struct pt_regs *uregs)

{

	*uregs = *task_pt_regs(child);



	/* Set up flags ABI bits. */

	uregs->flags = 0;

#ifdef CONFIG_COMPAT

	if (task_thread_info(child)->status & TS_COMPAT)

		uregs->flags |= PT_FLAGS_COMPAT;

#endif



	return (char *)uregs;

}



/* Put registers back to task. */

static void putregs(struct task_struct *child, struct pt_regs *uregs)

{

	struct pt_regs *regs = task_pt_regs(child);



	/* Don't allow overwriting the kernel-internal flags word. */

	uregs->flags = regs->flags;



	/* Only allow setting the ICS bit in the ex1 word. */

	uregs->ex1 = PL_ICS_EX1(USER_PL, EX1_ICS(uregs->ex1));



	*regs = *uregs;

}



long arch_ptrace(struct task_struct *child, long request,

		 unsigned long addr, unsigned long data)

{
@@ -53,14 +88,13 @@ long arch_ptrace(struct task_struct *child, long request, 
	long ret = -EIO;

	char *childreg;

	struct pt_regs copyregs;

	int ex1_offset;



	switch (request) {



	case PTRACE_PEEKUSR:  /* Read register from pt_regs. */

		if (addr >= PTREGS_SIZE)

			break;

		childreg = (char *)task_pt_regs(child) + addr;

		childreg = getregs(child, &copyregs) + addr;

#ifdef CONFIG_COMPAT

		if (is_compat_task()) {

			if (addr & (sizeof(compat_long_t)-1))
@@ -79,17 +113,7 @@ long arch_ptrace(struct task_struct *child, long request, 
	case PTRACE_POKEUSR:  /* Write register in pt_regs. */

		if (addr >= PTREGS_SIZE)

			break;

		childreg = (char *)task_pt_regs(child) + addr;



		/* Guard against overwrites of the privilege level. */

		ex1_offset = PTREGS_OFFSET_EX1;

#if defined(CONFIG_COMPAT) && defined(__BIG_ENDIAN)

		if (is_compat_task())   /* point at low word */

			ex1_offset += sizeof(compat_long_t);

#endif

		if (addr == ex1_offset)

			data = PL_ICS_EX1(USER_PL, EX1_ICS(data));



		childreg = getregs(child, &copyregs) + addr;

#ifdef CONFIG_COMPAT

		if (is_compat_task()) {

			if (addr & (sizeof(compat_long_t)-1))
@@ -102,11 +126,12 @@ long arch_ptrace(struct task_struct *child, long request, 
				break;

			*(long *)childreg = data;

		}

		putregs(child, &copyregs);

		ret = 0;

		break;



	case PTRACE_GETREGS:  /* Get all registers from the child. */

		if (copy_to_user(datap, task_pt_regs(child),

		if (copy_to_user(datap, getregs(child, &copyregs),

				 sizeof(struct pt_regs)) == 0) {

			ret = 0;

		}
@@ -115,9 +140,7 @@ long arch_ptrace(struct task_struct *child, long request, 
	case PTRACE_SETREGS:  /* Set all registers in the child. */

		if (copy_from_user(&copyregs, datap,

				   sizeof(struct pt_regs)) == 0) {

			copyregs.ex1 =

				PL_ICS_EX1(USER_PL, EX1_ICS(copyregs.ex1));

			*task_pt_regs(child) = copyregs;

			putregs(child, &copyregs);

			ret = 0;

		}

		break;