Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 5f09c77d authored by Mike Frysinger's avatar Mike Frysinger
Browse files

Blackfin: simplify SYSCFG code a bit and ignore attempts to change it 



We don't want to let user space modify the SYSCFG register arbitrarily as
the settings are system wide (SNEN/CNEN) and can cause misbehavior.  The
only other bit here (SSSTEP) has proper controls via PTRACE_SINGLESTEP.

Signed-off-by: default avatarMike Frysinger <vapier@gentoo.org>
parent f5b99627

arch/blackfin/kernel/ptrace.c

+6 −18
Original line number Diff line number Diff line
@@ -31,12 +31,6 @@ 
 * in exit.c or in signal.c.

 */



/* determines which bits in the SYSCFG reg the user has access to. */

/* 1 = access 0 = no access */

#define SYSCFG_MASK 0x0007	/* SYSCFG reg */

/* sets the trace bits. */

#define TRACE_BITS 0x0001



/* Find the stack offset for a register, relative to thread.esp0. */

#define PT_REG(reg)	((long)&((struct pt_regs *)0)->reg)
@@ -162,9 +156,8 @@ static inline int is_user_addr_valid(struct task_struct *child, 


void ptrace_enable(struct task_struct *child)

{

	unsigned long tmp;

	tmp = get_reg(child, PT_SYSCFG) | (TRACE_BITS);

	put_reg(child, PT_SYSCFG, tmp);

	struct pt_regs *regs = task_pt_regs(child);

	regs->syscfg |= SYSCFG_SSSTEP;

}



/*
@@ -174,10 +167,8 @@ void ptrace_enable(struct task_struct *child) 
 */

void ptrace_disable(struct task_struct *child)

{

	unsigned long tmp;

	/* make sure the single step bit is not set. */

	tmp = get_reg(child, PT_SYSCFG) & ~TRACE_BITS;

	put_reg(child, PT_SYSCFG, tmp);

	struct pt_regs *regs = task_pt_regs(child);

	regs->syscfg &= ~SYSCFG_SSSTEP;

}



long arch_ptrace(struct task_struct *child, long request, long addr, long data)
@@ -343,14 +334,11 @@ long arch_ptrace(struct task_struct *child, long request, long addr, long data) 
			break;

		}



		if (addr >= (sizeof(struct pt_regs))) {

		/* Ignore writes to SYSCFG and other pseudo regs */

		if (addr >= PT_SYSCFG) {

			ret = 0;

			break;

		}

		if (addr == PT_SYSCFG) {

			data &= SYSCFG_MASK;

			data |= get_reg(child, PT_SYSCFG);

		}

		ret = put_reg(child, addr, data);

		break;