arm64: mm: Rework unhandled user pagefaults to call arm64_force_sig_info

Reporting unhandled user pagefaults via arm64_force_sig_info means
that __do_user_fault can be drastically simplified, since it no longer
has to worry about printing the fault information and can consequently
just take the siginfo as a parameter.

Signed-off-by: Will Deacon <will.deacon@arm.com>

diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c
index fd5928a..49dfb08 100644 (file)
--- a/arch/arm64/mm/fault.c
+++ b/arch/arm64/mm/fault.c
@@ -43,6 +43,7 @@
 #include <asm/system_misc.h>
 #include <asm/pgtable.h>
 #include <asm/tlbflush.h>
+#include <asm/traps.h>
 
 #include <acpi/ghes.h>
 
@@ -289,58 +290,31 @@ static void __do_kernel_fault(unsigned long addr, unsigned int esr,
        do_exit(SIGKILL);
 }
 
-static void __do_user_fault(struct task_struct *tsk, unsigned long addr,
-                           unsigned int esr, unsigned int sig, int code,
-                           struct pt_regs *regs, int fault)
+static void __do_user_fault(struct siginfo *info, unsigned int esr)
 {
-       struct siginfo si;
-       const struct fault_info *inf;
-       unsigned int lsb = 0;
-
-       if (unhandled_signal(tsk, sig) && show_unhandled_signals_ratelimited()) {
-               inf = esr_to_fault_info(esr);
-               pr_info("%s[%d]: unhandled %s (%d) at 0x%08lx, esr 0x%03x",
-                       tsk->comm, task_pid_nr(tsk), inf->name, sig,
-                       addr, esr);
-               print_vma_addr(KERN_CONT ", in ", regs->pc);
-               pr_cont("\n");
-               __show_regs(regs);
-       }
-
-       tsk->thread.fault_address = addr;
-       tsk->thread.fault_code = esr;
-       si.si_signo = sig;
-       si.si_errno = 0;
-       si.si_code = code;
-       si.si_addr = (void __user *)addr;
-       /*
-        * Either small page or large page may be poisoned.
-        * In other words, VM_FAULT_HWPOISON_LARGE and
-        * VM_FAULT_HWPOISON are mutually exclusive.
-        */
-       if (fault & VM_FAULT_HWPOISON_LARGE)
-               lsb = hstate_index_to_shift(VM_FAULT_GET_HINDEX(fault));
-       else if (fault & VM_FAULT_HWPOISON)
-               lsb = PAGE_SHIFT;
-       si.si_addr_lsb = lsb;
-
-       force_sig_info(sig, &si, tsk);
+       current->thread.fault_address = (unsigned long)info->si_addr;
+       current->thread.fault_code = esr;
+       arm64_force_sig_info(info, esr_to_fault_info(esr)->name, current);
 }
 
 static void do_bad_area(unsigned long addr, unsigned int esr, struct pt_regs *regs)
 {
-       struct task_struct *tsk = current;
-       const struct fault_info *inf;
-
        /*
         * If we are in kernel mode at this point, we have no context to
         * handle this fault with.
         */
        if (user_mode(regs)) {
-               inf = esr_to_fault_info(esr);
-               __do_user_fault(tsk, addr, esr, inf->sig, inf->code, regs, 0);
-       } else
+               const struct fault_info *inf = esr_to_fault_info(esr);
+               struct siginfo si = {
+                       .si_signo       = inf->sig,
+                       .si_code        = inf->code,
+                       .si_addr        = (void __user *)addr,
+               };
+
+               __do_user_fault(&si, esr);
+       } else {
                __do_kernel_fault(addr, esr, regs);
+       }
 }
 
 #define VM_FAULT_BADMAP                0x010000
@@ -393,7 +367,8 @@ static int __kprobes do_page_fault(unsigned long addr, unsigned int esr,
 {
        struct task_struct *tsk;
        struct mm_struct *mm;
-       int fault, sig, code, major = 0;
+       struct siginfo si;
+       int fault, major = 0;
        unsigned long vm_flags = VM_READ | VM_WRITE;
        unsigned int mm_flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;
 
@@ -525,27 +500,37 @@ retry:
                return 0;
        }
 
+       clear_siginfo(&si);
+       si.si_addr = (void __user *)addr;
+
        if (fault & VM_FAULT_SIGBUS) {
                /*
                 * We had some memory, but were unable to successfully fix up
                 * this page fault.
                 */
-               sig = SIGBUS;
-               code = BUS_ADRERR;
-       } else if (fault & (VM_FAULT_HWPOISON | VM_FAULT_HWPOISON_LARGE)) {
-               sig = SIGBUS;
-               code = BUS_MCEERR_AR;
+               si.si_signo     = SIGBUS;
+               si.si_code      = BUS_ADRERR;
+       } else if (fault & VM_FAULT_HWPOISON_LARGE) {
+               unsigned int hindex = VM_FAULT_GET_HINDEX(fault);
+
+               si.si_signo     = SIGBUS;
+               si.si_code      = BUS_MCEERR_AR;
+               si.si_addr_lsb  = hstate_index_to_shift(hindex);
+       } else if (fault & VM_FAULT_HWPOISON) {
+               si.si_signo     = SIGBUS;
+               si.si_code      = BUS_MCEERR_AR;
+               si.si_addr_lsb  = PAGE_SHIFT;
        } else {
                /*
                 * Something tried to access memory that isn't in our memory
                 * map.
                 */
-               sig = SIGSEGV;
-               code = fault == VM_FAULT_BADACCESS ?
-                       SEGV_ACCERR : SEGV_MAPERR;
+               si.si_signo     = SIGSEGV;
+               si.si_code      = fault == VM_FAULT_BADACCESS ?
+                                 SEGV_ACCERR : SEGV_MAPERR;
        }
 
-       __do_user_fault(tsk, addr, esr, sig, code, regs, fault);
+       __do_user_fault(&si, esr);
        return 0;
 
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