[POWERPC] 40x/Book-E: Save/restore volatile exception registers
authorKumar Gala <galak@kernel.crashing.org>
Wed, 30 Apr 2008 10:23:21 +0000 (05:23 -0500)
committerKumar Gala <galak@kernel.crashing.org>
Mon, 2 Jun 2008 19:56:35 +0000 (14:56 -0500)
On machines with more than one exception level any system register that
might be modified by the "normal" exception level needs to be saved and
restored on taking a higher level exception.  We already are saving
and restoring ESR and DEAR.

For critical level add SRR0/1.
For debug level add CSRR0/1 and SRR0/1.
For machine check level add DSRR0/1, CSRR0/1, and SRR0/1.

On FSL Book-E parts we always save/restore the MAS registers for critical,
debug, and machine check level exceptions.  On 44x we always save/restore
the MMUCR.

Additionally, we save and restore the ksp_limit since we have to adjust it
for each exception level.

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Acked-by: Paul Mackerras <paulus@samba.org>
arch/powerpc/kernel/asm-offsets.c
arch/powerpc/kernel/entry_32.S
arch/powerpc/kernel/head_40x.S
arch/powerpc/kernel/head_booke.h

index ec9228d687b08515319694001c6c1feffb577944..8655c7670350a22c46fc92d2552edff67d2230a2 100644 (file)
 #include <asm/iseries/alpaca.h>
 #endif
 
+#if defined(CONFIG_BOOKE) || defined(CONFIG_40x)
+#include "head_booke.h"
+#endif
+
 int main(void)
 {
        DEFINE(THREAD, offsetof(struct task_struct, thread));
@@ -242,6 +246,25 @@ int main(void)
        DEFINE(_SRR1, STACK_FRAME_OVERHEAD+sizeof(struct pt_regs)+8);
 #endif /* CONFIG_PPC64 */
 
+#if defined(CONFIG_BOOKE) || defined(CONFIG_40x)
+       DEFINE(EXC_LVL_SIZE, STACK_EXC_LVL_FRAME_SIZE);
+       DEFINE(MAS0, STACK_INT_FRAME_SIZE+offsetof(struct exception_regs, mas0));
+       /* we overload MMUCR for 44x on MAS0 since they are mutually exclusive */
+       DEFINE(MMUCR, STACK_INT_FRAME_SIZE+offsetof(struct exception_regs, mas0));
+       DEFINE(MAS1, STACK_INT_FRAME_SIZE+offsetof(struct exception_regs, mas1));
+       DEFINE(MAS2, STACK_INT_FRAME_SIZE+offsetof(struct exception_regs, mas2));
+       DEFINE(MAS3, STACK_INT_FRAME_SIZE+offsetof(struct exception_regs, mas3));
+       DEFINE(MAS6, STACK_INT_FRAME_SIZE+offsetof(struct exception_regs, mas6));
+       DEFINE(MAS7, STACK_INT_FRAME_SIZE+offsetof(struct exception_regs, mas7));
+       DEFINE(_SRR0, STACK_INT_FRAME_SIZE+offsetof(struct exception_regs, srr0));
+       DEFINE(_SRR1, STACK_INT_FRAME_SIZE+offsetof(struct exception_regs, srr1));
+       DEFINE(_CSRR0, STACK_INT_FRAME_SIZE+offsetof(struct exception_regs, csrr0));
+       DEFINE(_CSRR1, STACK_INT_FRAME_SIZE+offsetof(struct exception_regs, csrr1));
+       DEFINE(_DSRR0, STACK_INT_FRAME_SIZE+offsetof(struct exception_regs, dsrr0));
+       DEFINE(_DSRR1, STACK_INT_FRAME_SIZE+offsetof(struct exception_regs, dsrr1));
+       DEFINE(SAVED_KSP_LIMIT, STACK_INT_FRAME_SIZE+offsetof(struct exception_regs, saved_ksp_limit));
+#endif
+
        DEFINE(CLONE_VM, CLONE_VM);
        DEFINE(CLONE_UNTRACED, CLONE_UNTRACED);
 
index c94aba54b5dd75f64aadbb4056e529807b7d7f14..fe21674d4f0687557e349af5512a97eb961b1dba 100644 (file)
 #ifdef CONFIG_BOOKE
        .globl  mcheck_transfer_to_handler
 mcheck_transfer_to_handler:
-       b       transfer_to_handler_full
+       mfspr   r0,SPRN_DSRR0
+       stw     r0,_DSRR0(r11)
+       mfspr   r0,SPRN_DSRR1
+       stw     r0,_DSRR1(r11)
+       /* fall through */
 
        .globl  debug_transfer_to_handler
 debug_transfer_to_handler:
-       b       transfer_to_handler_full
+       mfspr   r0,SPRN_CSRR0
+       stw     r0,_CSRR0(r11)
+       mfspr   r0,SPRN_CSRR1
+       stw     r0,_CSRR1(r11)
+       /* fall through */
 
        .globl  crit_transfer_to_handler
 crit_transfer_to_handler:
+#ifdef CONFIG_FSL_BOOKE
+       mfspr   r0,SPRN_MAS0
+       stw     r0,MAS0(r11)
+       mfspr   r0,SPRN_MAS1
+       stw     r0,MAS1(r11)
+       mfspr   r0,SPRN_MAS2
+       stw     r0,MAS2(r11)
+       mfspr   r0,SPRN_MAS3
+       stw     r0,MAS3(r11)
+       mfspr   r0,SPRN_MAS6
+       stw     r0,MAS6(r11)
+#ifdef CONFIG_PHYS_64BIT
+       mfspr   r0,SPRN_MAS7
+       stw     r0,MAS7(r11)
+#endif /* CONFIG_PHYS_64BIT */
+#endif /* CONFIG_FSL_BOOKE */
+#ifdef CONFIG_44x
+       mfspr   r0,SPRN_MMUCR
+       stw     r0,MMUCR(r11)
+#endif
+       mfspr   r0,SPRN_SRR0
+       stw     r0,_SRR0(r11)
+       mfspr   r0,SPRN_SRR1
+       stw     r0,_SRR1(r11)
+
+       mfspr   r8,SPRN_SPRG3
+       lwz     r0,KSP_LIMIT(r8)
+       stw     r0,SAVED_KSP_LIMIT(r11)
+       rlwimi  r0,r1,0,0,(31-THREAD_SHIFT)
+       stw     r0,KSP_LIMIT(r8)
        /* fall through */
 #endif
 
@@ -64,6 +102,16 @@ crit_transfer_to_handler:
        stw     r0,GPR10(r11)
        lwz     r0,crit_r11@l(0)
        stw     r0,GPR11(r11)
+       mfspr   r0,SPRN_SRR0
+       stw     r0,crit_srr0@l(0)
+       mfspr   r0,SPRN_SRR1
+       stw     r0,crit_srr1@l(0)
+
+       mfspr   r8,SPRN_SPRG3
+       lwz     r0,KSP_LIMIT(r8)
+       stw     r0,saved_ksp_limit@l(0)
+       rlwimi  r0,r1,0,0,(31-THREAD_SHIFT)
+       stw     r0,KSP_LIMIT(r8)
        /* fall through */
 #endif
 
@@ -854,17 +902,90 @@ exc_exit_restart_end:
        exc_lvl_rfi;                                                    \
        b       .;              /* prevent prefetch past exc_lvl_rfi */
 
+#define        RESTORE_xSRR(exc_lvl_srr0, exc_lvl_srr1)                        \
+       lwz     r9,_##exc_lvl_srr0(r1);                                 \
+       lwz     r10,_##exc_lvl_srr1(r1);                                \
+       mtspr   SPRN_##exc_lvl_srr0,r9;                                 \
+       mtspr   SPRN_##exc_lvl_srr1,r10;
+
+#if defined(CONFIG_FSL_BOOKE)
+#ifdef CONFIG_PHYS_64BIT
+#define        RESTORE_MAS7                                                    \
+       lwz     r11,MAS7(r1);                                           \
+       mtspr   SPRN_MAS7,r11;
+#else
+#define        RESTORE_MAS7
+#endif /* CONFIG_PHYS_64BIT */
+#define RESTORE_MMU_REGS                                               \
+       lwz     r9,MAS0(r1);                                            \
+       lwz     r10,MAS1(r1);                                           \
+       lwz     r11,MAS2(r1);                                           \
+       mtspr   SPRN_MAS0,r9;                                           \
+       lwz     r9,MAS3(r1);                                            \
+       mtspr   SPRN_MAS1,r10;                                          \
+       lwz     r10,MAS6(r1);                                           \
+       mtspr   SPRN_MAS2,r11;                                          \
+       mtspr   SPRN_MAS3,r9;                                           \
+       mtspr   SPRN_MAS6,r10;                                          \
+       RESTORE_MAS7;
+#elif defined(CONFIG_44x)
+#define RESTORE_MMU_REGS                                               \
+       lwz     r9,MMUCR(r1);                                           \
+       mtspr   SPRN_MMUCR,r9;
+#else
+#define RESTORE_MMU_REGS
+#endif
+
+#ifdef CONFIG_40x
        .globl  ret_from_crit_exc
 ret_from_crit_exc:
+       mfspr   r9,SPRN_SPRG3
+       lis     r10,saved_ksp_limit@ha;
+       lwz     r10,saved_ksp_limit@l(r10);
+       tovirt(r9,r9);
+       stw     r10,KSP_LIMIT(r9)
+       lis     r9,crit_srr0@ha;
+       lwz     r9,crit_srr0@l(r9);
+       lis     r10,crit_srr1@ha;
+       lwz     r10,crit_srr1@l(r10);
+       mtspr   SPRN_SRR0,r9;
+       mtspr   SPRN_SRR1,r10;
        RET_FROM_EXC_LEVEL(SPRN_CSRR0, SPRN_CSRR1, RFCI)
+#endif /* CONFIG_40x */
 
 #ifdef CONFIG_BOOKE
+       .globl  ret_from_crit_exc
+ret_from_crit_exc:
+       mfspr   r9,SPRN_SPRG3
+       lwz     r10,SAVED_KSP_LIMIT(r1)
+       stw     r10,KSP_LIMIT(r9)
+       RESTORE_xSRR(SRR0,SRR1);
+       RESTORE_MMU_REGS;
+       RET_FROM_EXC_LEVEL(SPRN_CSRR0, SPRN_CSRR1, RFCI)
+
        .globl  ret_from_debug_exc
 ret_from_debug_exc:
+       mfspr   r9,SPRN_SPRG3
+       lwz     r10,SAVED_KSP_LIMIT(r1)
+       stw     r10,KSP_LIMIT(r9)
+       lwz     r9,THREAD_INFO-THREAD(r9)
+       rlwinm  r10,r1,0,0,(31-THREAD_SHIFT)
+       lwz     r10,TI_PREEMPT(r10)
+       stw     r10,TI_PREEMPT(r9)
+       RESTORE_xSRR(SRR0,SRR1);
+       RESTORE_xSRR(CSRR0,CSRR1);
+       RESTORE_MMU_REGS;
        RET_FROM_EXC_LEVEL(SPRN_DSRR0, SPRN_DSRR1, RFDI)
 
        .globl  ret_from_mcheck_exc
 ret_from_mcheck_exc:
+       mfspr   r9,SPRN_SPRG3
+       lwz     r10,SAVED_KSP_LIMIT(r1)
+       stw     r10,KSP_LIMIT(r9)
+       RESTORE_xSRR(SRR0,SRR1);
+       RESTORE_xSRR(CSRR0,CSRR1);
+       RESTORE_xSRR(DSRR0,DSRR1);
+       RESTORE_MMU_REGS;
        RET_FROM_EXC_LEVEL(SPRN_MCSRR0, SPRN_MCSRR1, RFMCI)
 #endif /* CONFIG_BOOKE */
 
index f2cf60d38f78953a2273785c4d19fc61f279fa2a..56d8e5d90c5be0b0518dcefaf2262a8ae97bd5da 100644 (file)
@@ -93,6 +93,12 @@ _ENTRY(crit_r10)
        .space  4
 _ENTRY(crit_r11)
        .space  4
+_ENTRY(crit_srr0)
+       .space  4
+_ENTRY(crit_srr1)
+       .space  4
+_ENTRY(saved_ksp_limit)
+       .space  4
 
 /*
  * Exception vector entry code. This code runs with address translation
index b0874d228eaf99edf15c6349d48bb66c55bfb854..f277fade19328e015149e950978f035eea1fac72 100644 (file)
@@ -72,7 +72,7 @@
 #define DEBUG_STACK_BASE       dbgirq_ctx
 #define DEBUG_SPRG             SPRN_SPRG6W
 
-#define EXC_LVL_FRAME_OVERHEAD (THREAD_SIZE - INT_FRAME_SIZE)
+#define EXC_LVL_FRAME_OVERHEAD (THREAD_SIZE - INT_FRAME_SIZE - EXC_LVL_SIZE)
 
 #ifdef CONFIG_SMP
 #define BOOKE_LOAD_EXC_LEVEL_STACK(level)              \
@@ -376,4 +376,25 @@ label:
        addi    r3,r1,STACK_FRAME_OVERHEAD;                                   \
        EXC_XFER_EE_LITE(0x800, kernel_fp_unavailable_exception)
 
+#ifndef __ASSEMBLY__
+struct exception_regs {
+       unsigned long mas0;
+       unsigned long mas1;
+       unsigned long mas2;
+       unsigned long mas3;
+       unsigned long mas6;
+       unsigned long mas7;
+       unsigned long srr0;
+       unsigned long srr1;
+       unsigned long csrr0;
+       unsigned long csrr1;
+       unsigned long dsrr0;
+       unsigned long dsrr1;
+       unsigned long saved_ksp_limit;
+};
+
+/* ensure this structure is always sized to a multiple of the stack alignment */
+#define STACK_EXC_LVL_FRAME_SIZE       _ALIGN_UP(sizeof (struct exception_regs), 16)
+
+#endif /* __ASSEMBLY__ */
 #endif /* __HEAD_BOOKE_H__ */