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| author | Roland McGrath <roland@redhat.com> | 2008-01-30 13:30:50 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2008-01-30 13:30:50 +0100 |
| commit | e1f287735c1e58c653b516931b5d3dd899edcb77 (patch) | |
| tree | 1a2948cfe8ff679135971e2c573d11b847fee93d /arch/x86/ia32 | |
| parent | 7122ec8158b0f88befd94f4da8feae2c8d08d1b4 (diff) | |
| download | linux-e1f287735c1e58c653b516931b5d3dd899edcb77.tar.bz2 | |
x86 single_step: TIF_FORCED_TF
This changes the single-step support to use a new thread_info flag
TIF_FORCED_TF instead of the PT_DTRACE flag in task_struct.ptrace.
This keeps arch implementation uses out of this non-arch field.
This changes the ptrace access to eflags to mask TF and maintain
the TIF_FORCED_TF flag directly if userland sets TF, instead of
relying on ptrace_signal_deliver. The 64-bit and 32-bit kernels
are harmonized on this same behavior. The ptrace_signal_deliver
approach works now, but this change makes the low-level register
access code reliable when called from different contexts than a
ptrace stop, which will be possible in the future.
The 64-bit do_debug exception handler is also changed not to clear TF
from user-mode registers. This matches the 32-bit kernel's behavior.
Signed-off-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'arch/x86/ia32')
| -rw-r--r-- | arch/x86/ia32/ptrace32.c | 20 |
1 files changed, 18 insertions, 2 deletions
diff --git a/arch/x86/ia32/ptrace32.c b/arch/x86/ia32/ptrace32.c index 9d754b640205..5dee33417313 100644 --- a/arch/x86/ia32/ptrace32.c +++ b/arch/x86/ia32/ptrace32.c @@ -89,6 +89,15 @@ static int putreg32(struct task_struct *child, unsigned regno, u32 val) __u64 *flags = &stack[offsetof(struct pt_regs, eflags)/8]; val &= FLAG_MASK; + /* + * If the user value contains TF, mark that + * it was not "us" (the debugger) that set it. + * If not, make sure it stays set if we had. + */ + if (val & X86_EFLAGS_TF) + clear_tsk_thread_flag(child, TIF_FORCED_TF); + else if (test_tsk_thread_flag(child, TIF_FORCED_TF)) + val |= X86_EFLAGS_TF; *flags = val | (*flags & ~FLAG_MASK); break; } @@ -179,9 +188,17 @@ static int getreg32(struct task_struct *child, unsigned regno, u32 *val) R32(eax, rax); R32(orig_eax, orig_rax); R32(eip, rip); - R32(eflags, eflags); R32(esp, rsp); + case offsetof(struct user32, regs.eflags): + /* + * If the debugger set TF, hide it from the readout. + */ + *val = stack[offsetof(struct pt_regs, eflags)/8]; + if (test_tsk_thread_flag(child, TIF_FORCED_TF)) + *val &= ~X86_EFLAGS_TF; + break; + case offsetof(struct user32, u_debugreg[0]): *val = child->thread.debugreg0; break; @@ -425,4 +442,3 @@ asmlinkage long sys32_ptrace(long request, u32 pid, u32 addr, u32 data) put_task_struct(child); return ret; } - |