Automatic merge with /usr/src/ntfs-2.6.git.

1 files changed, 58 insertions, 0 deletions

diff --git a/arch/arm/kernel/traps.c b/arch/arm/kernel/traps.c
index 14df16b983f4..2fb0a4cfb37a 100644
--- a/arch/arm/kernel/traps.c
+++ b/arch/arm/kernel/traps.c
@@ -30,6 +30,7 @@
 #include <asm/traps.h>
 
 #include "ptrace.h"
+#include "signal.h"
 
 const char *processor_modes[]=
 { "USER_26", "FIQ_26" , "IRQ_26" , "SVC_26" , "UK4_26" , "UK5_26" , "UK6_26" , "UK7_26" ,
@@ -464,6 +465,55 @@ asmlinkage int arm_syscall(int no, struct pt_regs *regs)
 #endif
                 return 0;
 
+#ifdef CONFIG_NEEDS_SYSCALL_FOR_CMPXCHG
+        /*
+         * Atomically store r1 in *r2 if *r2 is equal to r0 for user space.
+         * Return zero in r0 if *MEM was changed or non-zero if no exchange
+         * happened.  Also set the user C flag accordingly.
+         * If access permissions have to be fixed up then non-zero is
+         * returned and the operation has to be re-attempted.
+         *
+         * *NOTE*: This is a ghost syscall private to the kernel.  Only the
+         * __kuser_cmpxchg code in entry-armv.S should be aware of its
+         * existence.  Don't ever use this from user code.
+         */
+        case 0xfff0:
+        {
+                extern void do_DataAbort(unsigned long addr, unsigned int fsr,
+                                         struct pt_regs *regs);
+                unsigned long val;
+                unsigned long addr = regs->ARM_r2;
+                struct mm_struct *mm = current->mm;
+                pgd_t *pgd; pmd_t *pmd; pte_t *pte;
+
+                regs->ARM_cpsr &= ~PSR_C_BIT;
+                spin_lock(&mm->page_table_lock);
+                pgd = pgd_offset(mm, addr);
+                if (!pgd_present(*pgd))
+                        goto bad_access;
+                pmd = pmd_offset(pgd, addr);
+                if (!pmd_present(*pmd))
+                        goto bad_access;
+                pte = pte_offset_map(pmd, addr);
+                if (!pte_present(*pte) || !pte_write(*pte))
+                        goto bad_access;
+                val = *(unsigned long *)addr;
+                val -= regs->ARM_r0;
+                if (val == 0) {
+                        *(unsigned long *)addr = regs->ARM_r1;
+                        regs->ARM_cpsr |= PSR_C_BIT;
+                }
+                spin_unlock(&mm->page_table_lock);
+                return val;
+
+                bad_access:
+                spin_unlock(&mm->page_table_lock);
+                /* simulate a read access fault */
+                do_DataAbort(addr, 15 + (1 << 11), regs);
+                return -1;
+        }
+#endif
+
         default:
                 /* Calls 9f00xx..9f07ff are defined to return -ENOSYS
                    if not implemented, rather than raising SIGILL.  This
@@ -634,6 +684,14 @@ void __init trap_init(void)
         memcpy((void *)0xffff0000, __vectors_start, __vectors_end - __vectors_start);
         memcpy((void *)0xffff0200, __stubs_start, __stubs_end - __stubs_start);
         memcpy((void *)0xffff1000 - kuser_sz, __kuser_helper_start, kuser_sz);
+
+        /*
+         * Copy signal return handlers into the vector page, and
+         * set sigreturn to be a pointer to these.
+         */
+        memcpy((void *)KERN_SIGRETURN_CODE, sigreturn_codes,
+               sizeof(sigreturn_codes));
+
         flush_icache_range(0xffff0000, 0xffff0000 + PAGE_SIZE);
         modify_domain(DOMAIN_USER, DOMAIN_CLIENT);
 }