powerpc: Fix system calls on Cell entered with XER.SO=1

[safe/jmp/linux-2.6] / arch / powerpc / kernel / entry_64.S

diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S
index 2d802e9..e0bcf93 100644 (file)
--- a/arch/powerpc/kernel/entry_64.S
+++ b/arch/powerpc/kernel/entry_64.S
@@ -57,12 +57,18 @@ system_call_common:
        beq-    1f
        ld      r1,PACAKSAVE(r13)
 1:     std     r10,0(r1)
-       crclr   so
        std     r11,_NIP(r1)
        std     r12,_MSR(r1)
        std     r0,GPR0(r1)
        std     r10,GPR1(r1)
        ACCOUNT_CPU_USER_ENTRY(r10, r11)
+       /*
+        * This "crclr so" clears CR0.SO, which is the error indication on
+        * return from this system call.  There must be no cmp instruction
+        * between it and the "mfcr r9" below, otherwise if XER.SO is set,
+        * CR0.SO will get set, causing all system calls to appear to fail.
+        */
+       crclr   so
        std     r2,GPR2(r1)
        std     r3,GPR3(r1)
        std     r4,GPR4(r1)
@@ -512,31 +518,12 @@ _GLOBAL(ret_from_except_lite)
 #endif
 
 restore:
-       ld      r5,SOFTE(r1)
-#ifdef CONFIG_PPC_ISERIES
 BEGIN_FW_FTR_SECTION
-       cmpdi   0,r5,0
-       beq     4f
-       /* Check for pending interrupts (iSeries) */
-       ld      r3,PACALPPACAPTR(r13)
-       ld      r3,LPPACAANYINT(r3)
-       cmpdi   r3,0
-       beq+    4f                      /* skip do_IRQ if no interrupts */
-
-       li      r3,0
-       stb     r3,PACASOFTIRQEN(r13)   /* ensure we are soft-disabled */
-#ifdef CONFIG_TRACE_IRQFLAGS
-       bl      .trace_hardirqs_off
-       mfmsr   r10
-#endif
-       ori     r10,r10,MSR_EE
-       mtmsrd  r10                     /* hard-enable again */
-       addi    r3,r1,STACK_FRAME_OVERHEAD
-       bl      .do_IRQ
-       b       .ret_from_except_lite           /* loop back and handle more */
-4:
-END_FW_FTR_SECTION_IFSET(FW_FEATURE_ISERIES)
-#endif
+       ld      r5,SOFTE(r1)
+FW_FTR_SECTION_ELSE
+       b       iseries_check_pending_irqs
+ALT_FW_FTR_SECTION_END_IFCLR(FW_FEATURE_ISERIES)
+2:
        TRACE_AND_RESTORE_IRQ(r5);
 
        /* extract EE bit and use it to restore paca->hard_enabled */
@@ -592,6 +579,30 @@ END_FW_FTR_SECTION_IFSET(FW_FEATURE_ISERIES)
        rfid
        b       .       /* prevent speculative execution */
 
+iseries_check_pending_irqs:
+#ifdef CONFIG_PPC_ISERIES
+       ld      r5,SOFTE(r1)
+       cmpdi   0,r5,0
+       beq     2b
+       /* Check for pending interrupts (iSeries) */
+       ld      r3,PACALPPACAPTR(r13)
+       ld      r3,LPPACAANYINT(r3)
+       cmpdi   r3,0
+       beq+    2b                      /* skip do_IRQ if no interrupts */
+
+       li      r3,0
+       stb     r3,PACASOFTIRQEN(r13)   /* ensure we are soft-disabled */
+#ifdef CONFIG_TRACE_IRQFLAGS
+       bl      .trace_hardirqs_off
+       mfmsr   r10
+#endif
+       ori     r10,r10,MSR_EE
+       mtmsrd  r10                     /* hard-enable again */
+       addi    r3,r1,STACK_FRAME_OVERHEAD
+       bl      .do_IRQ
+       b       .ret_from_except_lite           /* loop back and handle more */
+#endif
+
 do_work:
 #ifdef CONFIG_PREEMPT
        andi.   r0,r3,MSR_PR    /* Returning to user mode? */
@@ -685,10 +696,6 @@ _GLOBAL(enter_rtas)
        std     r7,_DAR(r1)
        mfdsisr r8
        std     r8,_DSISR(r1)
-       mfsrr0  r9
-       std     r9,_SRR0(r1)
-       mfsrr1  r10
-       std     r10,_SRR1(r1)
 
        /* Temporary workaround to clear CR until RTAS can be modified to
         * ignore all bits.
@@ -749,6 +756,10 @@ _STATIC(rtas_return_loc)
        mfspr   r4,SPRN_SPRG3           /* Get PACA */
        clrldi  r4,r4,2                 /* convert to realmode address */
 
+       bcl     20,31,$+4
+0:     mflr    r3
+       ld      r3,(1f-0b)(r3)          /* get &.rtas_restore_regs */
+
        mfmsr   r6
        li      r0,MSR_RI
        andc    r6,r6,r0
@@ -756,7 +767,6 @@ _STATIC(rtas_return_loc)
        mtmsrd  r6
         
         ld     r1,PACAR1(r4)           /* Restore our SP */
-       LOAD_REG_IMMEDIATE(r3,.rtas_restore_regs)
         ld     r4,PACASAVEDMSR(r4)     /* Restore our MSR */
 
        mtspr   SPRN_SRR0,r3
@@ -764,6 +774,9 @@ _STATIC(rtas_return_loc)
        rfid
        b       .       /* prevent speculative execution */
 
+       .align  3
+1:     .llong  .rtas_restore_regs
+
 _STATIC(rtas_restore_regs)
        /* relocation is on at this point */
        REST_GPR(2, r1)                 /* Restore the TOC */
@@ -783,10 +796,6 @@ _STATIC(rtas_restore_regs)
        mtdar   r7
        ld      r8,_DSISR(r1)
        mtdsisr r8
-       ld      r9,_SRR0(r1)
-       mtsrr0  r9
-       ld      r10,_SRR1(r1)
-       mtsrr1  r10
 
         addi   r1,r1,RTAS_FRAME_SIZE   /* Unstack our frame */
        ld      r0,16(r1)               /* get return address */
@@ -881,7 +890,7 @@ _GLOBAL(enter_prom)
        mtlr    r0
         blr
 
-#ifdef CONFIG_FTRACE
+#ifdef CONFIG_FUNCTION_TRACER
 #ifdef CONFIG_DYNAMIC_FTRACE
 _GLOBAL(mcount)
 _GLOBAL(_mcount)