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Reset segment registers 1-7 upon entry to kernel (via trap or interrupts)

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so that the bat spill code won't run into spurious valid user pages and
treat them as kernel pages.  Restore segment registers 1-7 upon return to
user mode from either a trap or interrupt.   XXX  eventually do all 16 SRs
This commit is contained in:
matt 2001-06-30 01:24:13 +00:00
parent 7c5977ea4f
commit 39fa08a172
1 changed files with 51 additions and 2 deletions
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53
sys/arch/powerpc/powerpc/trap_subr.S
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@ -1,4 +1,4 @@
/* $NetBSD: trap_subr.S,v 1.9 2001/06/23 02:36:14 matt Exp $ */
/* $NetBSD: trap_subr.S,v 1.10 2001/06/30 01:24:13 matt Exp $ */
/*
* Copyright (C) 1995, 1996 Wolfgang Solfrank.
@ -542,6 +542,20 @@ _C_LABEL(ipkdbsize) = .-_C_LABEL(ipkdblow)
/* Restore user & kernel access SR: */ \
lis 2,_C_LABEL(curpm)@ha; /* get real address of pmap */ \
lwz 2,_C_LABEL(curpm)@l(2); \
lwz 3,PM_SR+4(2); \
mtsr 1,3; /* restore SR1 */ \
lwz 3,PM_SR+8(2); \
mtsr 2,3; /* restore SR2 */ \
lwz 3,PM_SR+12(2); \
mtsr 3,3; /* restore SR3 */ \
lwz 3,PM_SR+16(2); \
mtsr 4,3; /* restore SR4 */ \
lwz 3,PM_SR+20(2); \
mtsr 5,3; /* restore SR5 */ \
lwz 3,PM_SR+24(2); \
mtsr 6,3; /* restore SR6 */ \
lwz 3,PM_SR+28(2); \
mtsr 7,3; /* restore SR7 */ \
lwz 3,PM_USRSR(2); \
mtsr USER_SR,3; \
lwz 3,PM_KERNELSR(2); \
@ -585,6 +599,16 @@ s_trap:
lis 31,KERNEL_SEGMENT@h
ori 31,31,KERNEL_SEGMENT@l
mtsr KERNEL_SR,31
/* Obliterate SRs so BAT spills work correctly */
lis 31,EMPTY_SEGMENT@h
ori 31,31,EMPTY_SEGMENT@l
mtsr 1,31
mtsr 2,31
mtsr 3,31
mtsr 4,31
mtsr 5,31
mtsr 6,31
mtsr 7,31
FRAME_SETUP(tempsave)
/* Now we can recover interrupts again: */
mfmsr 7
@ -729,11 +753,22 @@ s_isitrap:
stw 5,20(1); \
stw 4,12(1); \
stw 3,8(1); \
mtcr 3; \
bc 4,17,99f; /* branch if PSL_PR is false */ \
lis 3,EMPTY_SEGMENT@h; \
ori 3,3,EMPTY_SEGMENT@l; \
mtsr 1,3; /* reset SRs so BAT spills work */ \
mtsr 2,3; \
mtsr 3,3; \
mtsr 4,3; \
mtsr 5,3; \
mtsr 6,3; \
mtsr 7,3; \
/* interrupts are recoverable here, and enable translation */ \
lis 3,(KERNEL_SEGMENT|SR_SUKEY|SR_PRKEY)@h; \
ori 3,3,(KERNEL_SEGMENT|SR_SUKEY|SR_PRKEY)@l; \
mtsr KERNEL_SR,3; \
mfmsr 5; \
99: mfmsr 5; \
ori 5,5,(PSL_IR|PSL_DR|PSL_RI); \
mtmsr 5; \
isync
@ -770,6 +805,20 @@ intr_exit:
bc 4,17,1f /* branch if PSL_PR is false */
lis 3,_C_LABEL(curpm)@ha /* get current pmap real address */
lwz 3,_C_LABEL(curpm)@l(3)
lwz 4,PM_SR+4(3)
mtsr 1,4 /* Restore SR1 */
lwz 4,PM_SR+8(3)
mtsr 2,4 /* Restore SR2 */
lwz 4,PM_SR+12(3)
mtsr 3,4 /* Restore SR3 */
lwz 4,PM_SR+16(3)
mtsr 4,4 /* Restore SR4 */
lwz 4,PM_SR+20(3)
mtsr 5,4 /* Restore SR5 */
lwz 4,PM_SR+24(3)
mtsr 6,4 /* Restore SR6 */
lwz 4,PM_SR+28(3)
mtsr 7,4 /* Restore SR7 */
lwz 3,PM_KERNELSR(3)
mtsr KERNEL_SR,3 /* Restore kernel SR */
lis 3,_C_LABEL(astpending)@ha /* Test AST pending */