[PATCH] ARM: Add VST idle loop call

[linux-2.6-omap-h63xx.git] / arch / arm / kernel / traps.c

diff --git a/arch/arm/kernel/traps.c b/arch/arm/kernel/traps.c
index 14df16b983f4ca5c1c08c804ceb3df3659bec34c..2fb0a4cfb37a4af48c2365d500608ef871197e1a 100644 (file)
--- 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);
 }