On Fri, 2017-06-09 at 13:02 +0200, Borislav Petkov wrote:
On Fri, May 05, 2017 at 11:17:20AM -0700, Ricardo Neri wrote:
fixup_umip_exception() will be called from do_general_protection. If the
^ |Please end function names with parentheses. ---+
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
That reads funny.
I will correct this.
force_sig_info_fault is introduced to model the page fault.
Cc: Andy Lutomirski luto@kernel.org Cc: Andrew Morton akpm@linux-foundation.org Cc: H. Peter Anvin hpa@zytor.com Cc: Borislav Petkov bp@suse.de Cc: Brian Gerst brgerst@gmail.com Cc: Chen Yucong slaoub@gmail.com Cc: Chris Metcalf cmetcalf@mellanox.com Cc: Dave Hansen dave.hansen@linux.intel.com Cc: Fenghua Yu fenghua.yu@intel.com Cc: Huang Rui ray.huang@amd.com Cc: Jiri Slaby jslaby@suse.cz Cc: Jonathan Corbet corbet@lwn.net Cc: Michael S. Tsirkin mst@redhat.com Cc: Paul Gortmaker paul.gortmaker@windriver.com Cc: Peter Zijlstra peterz@infradead.org Cc: Ravi V. Shankar ravi.v.shankar@intel.com Cc: Shuah Khan shuah@kernel.org Cc: Vlastimil Babka vbabka@suse.cz Cc: Tony Luck tony.luck@intel.com Cc: Paolo Bonzini pbonzini@redhat.com Cc: Liang Z. Li liang.z.li@intel.com Cc: Alexandre Julliard julliard@winehq.org Cc: Stas Sergeev stsp@list.ru Cc: x86@kernel.org Cc: linux-msdos@vger.kernel.org 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 c7c5795..ff7366a 100644 --- a/arch/x86/kernel/umip.c +++ b/arch/x86/kernel/umip.c @@ -148,6 +148,41 @@ 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)) {
Save an indentation level:
if (!(show_unhandled_signals && unhandled_signal(tsk, SIGSEGV))) return;
printk...
I will implement like this.
printk_ratelimited("%s[%d] umip emulation segfault ip:%lx sp:%lx error:%x in %lx\n",tsk->comm, task_pid_nr(tsk), regs->ip,regs->sp, X86_PF_USER | X86_PF_WRITE,regs->ip);- }
- tsk->thread.cr2 = (unsigned long)address;
- tsk->thread.error_code = X86_PF_USER | X86_PF_WRITE;
- tsk->thread.trap_nr = X86_TRAP_PF;
- info.si_signo = SIGSEGV;
- info.si_errno = 0;
- info.si_code = SEGV_MAPERR;
- info.si_addr = address;
- force_sig_info(SIGSEGV, &info, tsk);
+}
+/**
- fixup_umip_exception() - Fixup #GP faults caused by UMIP
- @regs: Registers as saved when entering the #GP trap
@@ -235,8 +270,14 @@ bool fixup_umip_exception(struct pt_regs *regs) if ((unsigned long)uaddr == -1L) return false; nr_copied = copy_to_user(uaddr, dummy_data, dummy_data_size);
if (nr_copied > 0)return false;
if (nr_copied > 0) {/** If copy fails, send a signal and tell caller that* fault was fixed upPls end sentences in the comments with a fullstop.
I will correct this.
Thanks and BR, Ricardo