[PATCH 12/36] m68k: add ColdFire paging exception handling code

gerg
2011-10-25T07:19:24Z

Add code to traps.c to handle MMU exceptions for the ColdFire.
Most of this code is from the 2.6.25 kernel BSP code released by
Freescale.

Signed-off-by: Greg Ungerer <gerg@uclinux.org>
---
arch/m68k/kernel/traps.c | 104 ++++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 104 insertions(+), 0 deletions(-)

diff --git a/arch/m68k/kernel/traps.c b/arch/m68k/kernel/traps.c
index 89362f2..2ced994 100644
--- a/arch/m68k/kernel/traps.c
+++ b/arch/m68k/kernel/traps.c
@@ -706,8 +706,94 @@ create_atc_entry:
#endif /* CPU_M68020_OR_M68030 */
#endif /* !CONFIG_SUN3 */

+#if defined(CONFIG_COLDFIRE) && defined(CONFIG_MMU)
+#include <asm/mcfmmu.h>
+
+/*
+ * The following table converts the FS encoding of a ColdFire
+ * exception stack frame into the error_code value needed by
+ * do_fault.
+*/
+static const unsigned char fs_err_code[] = {
+ 0, /* 0000 */
+ 0, /* 0001 */
+ 0, /* 0010 */
+ 0, /* 0011 */
+ 1, /* 0100 */
+ 0, /* 0101 */
+ 0, /* 0110 */
+ 0, /* 0111 */
+ 2, /* 1000 */
+ 3, /* 1001 */
+ 2, /* 1010 */
+ 0, /* 1011 */
+ 1, /* 1100 */
+ 1, /* 1101 */
+ 0, /* 1110 */
+ 0 /* 1111 */
+};
+
+static inline void access_errorcf(unsigned int fs, struct frame *fp)
+{
+ unsigned long int mmusr, complainingAddress;
+ unsigned int err_code;
+ int need_page_fault;
+
+ mmusr = mmu_read(MMUSR);
+ complainingAddress = mmu_read(MMUAR);
+
+ /*
+ * error_code:
+ * bit 0 == 0 means no page found, 1 means protection fault
+ * bit 1 == 0 means read, 1 means write
+ */
+ switch (fs) {
+ case 5: /* 0101 TLB opword X miss */
+ need_page_fault = cf_tlb_miss(&fp->ptregs, 0, 0, 0);
+ complainingAddress = fp->ptregs.pc;
+ break;
+ case 6: /* 0110 TLB extension word X miss */
+ need_page_fault = cf_tlb_miss(&fp->ptregs, 0, 0, 1);
+ complainingAddress = fp->ptregs.pc + sizeof(long);
+ break;
+ case 10: /* 1010 TLB W miss */
+ need_page_fault = cf_tlb_miss(&fp->ptregs, 1, 1, 0);
+ break;
+ case 14: /* 1110 TLB R miss */
+ need_page_fault = cf_tlb_miss(&fp->ptregs, 0, 1, 0);
+ break;
+ default:
+ /* 0000 Normal */
+ /* 0001 Reserved */
+ /* 0010 Interrupt during debug service routine */
+ /* 0011 Reserved */
+ /* 0100 X Protection */
+ /* 0111 IFP in emulator mode */
+ /* 1000 W Protection*/
+ /* 1001 Write error*/
+ /* 1011 Reserved*/
+ /* 1100 R Protection*/
+ /* 1101 R Protection*/
+ /* 1111 OEP in emulator mode*/
+ need_page_fault = 1;
+ break;
+ }
+
+ if (need_page_fault) {
+ err_code = fs_err_code[fs];
+ if ((fs == 13) && (mmusr & MMUSR_WF)) /* rd-mod-wr access */
+ err_code |= 2; /* bit1 - write, bit0 - protection */
+ do_page_fault(&fp->ptregs, complainingAddress, err_code);
+ }
+}
+#endif /* CONFIG_COLDFIRE CONFIG_MMU */
+
asmlinkage void buserr_c(struct frame *fp)
{
+#if defined(CONFIG_COLDFIRE) && defined(CONFIG_MMU)
+ unsigned int fs;
+#endif
+
/* Only set esp0 if coming from user mode */
if (user_mode(&fp->ptregs))
current->thread.esp0 = (unsigned long) fp;
@@ -716,6 +802,24 @@ asmlinkage void buserr_c(struct frame *fp)
printk ("*** Bus Error *** Format is %x\n", fp->ptregs.format);
#endif

+#if defined(CONFIG_COLDFIRE) && defined(CONFIG_MMU)
+ fs = (fp->ptregs.vector & 0x3) | ((fp->ptregs.vector & 0xc00) >> 8);
+ switch (fs) {
+ case 0x5:
+ case 0x6:
+ case 0x7:
+ case 0x9:
+ case 0xa:
+ case 0xd:
+ case 0xe:
+ case 0xf:
+ access_errorcf(fs, fp);
+ return;
+ default:
+ break;
+ }
+#endif /* CONFIG_COLDFIRE CONFIG_MMU */
+
switch (fp->ptregs.format) {
#if defined (CONFIG_M68060)
case 4: /* 68060 access error */
--
1.7.0.4