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[POWERPC] Add 1TB workaround for PA6T 

PA6T has a bug where the slbie instruction does not honor the large
segment bit.  As a result, we have to always use slbia when switching
context.

We don't have to worry about changing the slbie's during fault processing,
since they should never be replacing one VSID with another using the
same ESID.  I.e. there's no risk for inserting duplicate entries due to a
failed slbie of the old entry.  So as long as we clear it out on context
switch we should be fine.

Signed-off-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Paul Mackerras <paulus@samba.org>
hifive-unleashed-5.1
Olof Johansson 2007-10-16 00:58:59 +10:00 committed by Paul Mackerras
parent 8129535b6b
commit f66bce5e6a
4 changed files with 11 additions and 2 deletions
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6
arch/powerpc/kernel/entry_64.S
View File

@ -408,6 +408,12 @@ END_FTR_SECTION_IFSET(CPU_FTR_1T_SEGMENT)
std r7,SLBSHADOW_STACKVSID(r9) /* Save VSID */
std r0,SLBSHADOW_STACKESID(r9) /* Save ESID */
/* No need to check for CPU_FTR_NO_SLBIE_B here, since when
* we have 1TB segments, the only CPUs known to have the errata
* only support less than 1TB of system memory and we'll never
* actually hit this code path.
*/
slbie r6
slbie r6 /* Workaround POWER5 < DD2.1 issue */
slbmte r7,r0

1
arch/powerpc/mm/hash_utils_64.c
View File

@ -212,6 +212,7 @@ static int __init htab_dt_scan_seg_sizes(unsigned long node,
return 1;
}
}
cur_cpu_spec->cpu_features &= ~CPU_FTR_NO_SLBIE_B;
return 0;
}

3
arch/powerpc/mm/slb.c
View File

@ -157,7 +157,8 @@ void switch_slb(struct task_struct *tsk, struct mm_struct *mm)
unsigned long stack = KSTK_ESP(tsk);
unsigned long unmapped_base;
if (offset <= SLB_CACHE_ENTRIES) {
if (!cpu_has_feature(CPU_FTR_NO_SLBIE_B) &&
offset <= SLB_CACHE_ENTRIES) {
int i;
asm volatile("isync" : : : "memory");
for (i = 0; i < offset; i++) {

3
include/asm-powerpc/cputable.h
View File

@ -165,6 +165,7 @@ extern void do_feature_fixups(unsigned long value, void *fixup_start,
#define CPU_FTR_SPURR LONG_ASM_CONST(0x0001000000000000)
#define CPU_FTR_DSCR LONG_ASM_CONST(0x0002000000000000)
#define CPU_FTR_1T_SEGMENT LONG_ASM_CONST(0x0004000000000000)
#define CPU_FTR_NO_SLBIE_B LONG_ASM_CONST(0x0008000000000000)
#ifndef __ASSEMBLY__
@ -367,7 +368,7 @@ extern void do_feature_fixups(unsigned long value, void *fixup_start,
#define CPU_FTRS_PA6T (CPU_FTR_USE_TB | \
CPU_FTR_HPTE_TABLE | CPU_FTR_PPCAS_ARCH_V2 | \
CPU_FTR_ALTIVEC_COMP | CPU_FTR_CI_LARGE_PAGE | \
CPU_FTR_PURR | CPU_FTR_REAL_LE)
CPU_FTR_PURR | CPU_FTR_REAL_LE | CPU_FTR_NO_SLBIE_B)
#define CPU_FTRS_COMPATIBLE (CPU_FTR_USE_TB | \
CPU_FTR_HPTE_TABLE | CPU_FTR_PPCAS_ARCH_V2)