On Fri, Mar 3, 2017 at 1:41 PM, Ricardo Neri ricardo.neri-calderon@linux.intel.com wrote:
fixup_umip_exception will be called from do_general_protection. If the former returns false, the latter will issue a SIGSEGV with SEND_SIG_PRIV. However, when emulation is successful but the emulated result cannot be copied to user space memory, it is more accurate to issue a SIGSEGV with SEGV_MAPERR with the offending address. A new function is inspired in force_sig_info_fault is introduced to model the page fault.
Signed-off-by: Ricardo Neri ricardo.neri-calderon@linux.intel.com
arch/x86/kernel/umip.c | 45 +++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 43 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kernel/umip.c b/arch/x86/kernel/umip.c index e932f40..5b6a7cf 100644 --- a/arch/x86/kernel/umip.c +++ b/arch/x86/kernel/umip.c @@ -170,6 +170,41 @@ static int __emulate_umip_insn(struct insn *insn, enum umip_insn umip_inst, }
/**
- __force_sig_info_umip_fault - Force a SIGSEGV with SEGV_MAPERR
- @address: Address that caused the signal
- @regs: Register set containing the instruction pointer
- Force a SIGSEGV signal with SEGV_MAPERR as the error code. This function is
- intended to be used to provide a segmentation fault when the result of the
- UMIP emulation could not be copied to the user space memory.
- Return: none
- */
+static void __force_sig_info_umip_fault(void __user *address,
struct pt_regs *regs)+{
siginfo_t info;struct task_struct *tsk = current;if (show_unhandled_signals && unhandled_signal(tsk, SIGSEGV)) {printk_ratelimited("%s[%d] umip emulation segfault ip:%lx sp:%lx error:%lx in %lx\n",tsk->comm, task_pid_nr(tsk), regs->ip,regs->sp, UMIP_PF_USER | UMIP_PF_WRITE,regs->ip);}tsk->thread.cr2 = (unsigned long)address;tsk->thread.error_code = UMIP_PF_USER | UMIP_PF_WRITE;
Please just move enum x86_pf_error_code into a header and rename the fields X86_PF_USER, etc rather than duplicating it.
--Andy