diff options
| author | Mike Frysinger <vapier@gentoo.org> | 2010-02-14 22:49:59 +0000 |
|---|---|---|
| committer | Mike Frysinger <vapier@gentoo.org> | 2010-03-09 00:30:51 -0500 |
| commit | 5f09c77d2ad69397498b6555f0d3cd697304253c (patch) | |
| tree | 0e14bceda7eb4eb756febbd838c6b87ef69890f4 | |
| parent | f5b99627a3065858ad5c678703ed7af5363dca39 (diff) | |
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: Mike Frysinger <vapier@gentoo.org>
| -rw-r--r-- | arch/blackfin/kernel/ptrace.c | 24 |
1 files changed, 6 insertions, 18 deletions
diff --git a/arch/blackfin/kernel/ptrace.c b/arch/blackfin/kernel/ptrace.c index 895302df21c1..14118e40f18f 100644 --- a/arch/blackfin/kernel/ptrace.c +++ b/arch/blackfin/kernel/ptrace.c @@ -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; |