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ARM: proc-v7: avoid errata 430973 workaround for non-Cortex A8 CPUs 

Avoid the errata 430973 workaround for non-Cortex A8 CPUs.  Having this
workaround enabled introduces an additional branch target buffer flush
into the context switching path, something we wish to avoid.  To allow
this errata to be enabled in multiplatform kernels while reducing its
impact, rearrange the Cortex-A8 CPU support to avoid impacting on other
Version 7 CPUs.

Tested-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Russell King 2015-04-07 15:35:24 +01:00
parent e5a5de4447
commit a6d7467898
2 changed files with 36 additions and 4 deletions
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12
arch/arm/mm/proc-v7-2level.S
View File

@ -37,15 +37,18 @@
* It is assumed that:
* - we are not using split page tables
*/
ENTRY(cpu_v7_switch_mm)
ENTRY(cpu_ca8_switch_mm)
#ifdef CONFIG_MMU
mov r2, #0
mmid r1, r1 @ get mm->context.id
ALT_SMP(orr r0, r0, #TTB_FLAGS_SMP)
ALT_UP(orr r0, r0, #TTB_FLAGS_UP)
#ifdef CONFIG_ARM_ERRATA_430973
mcr p15, 0, r2, c7, c5, 6 @ flush BTAC/BTB
#endif
#endif
ENTRY(cpu_v7_switch_mm)
#ifdef CONFIG_MMU
mmid r1, r1 @ get mm->context.id
ALT_SMP(orr r0, r0, #TTB_FLAGS_SMP)
ALT_UP(orr r0, r0, #TTB_FLAGS_UP)
#ifdef CONFIG_PID_IN_CONTEXTIDR
mrc p15, 0, r2, c13, c0, 1 @ read current context ID
lsr r2, r2, #8 @ extract the PID
@ -61,6 +64,7 @@ ENTRY(cpu_v7_switch_mm)
#endif
bx lr
ENDPROC(cpu_v7_switch_mm)
ENDPROC(cpu_ca8_switch_mm)
/*
* cpu_v7_set_pte_ext(ptep, pte)

28
arch/arm/mm/proc-v7.S
View File

@ -152,6 +152,21 @@ ENTRY(cpu_v7_do_resume)
ENDPROC(cpu_v7_do_resume)
#endif
/*
* Cortex-A8
*/
globl_equ cpu_ca8_proc_init, cpu_v7_proc_init
globl_equ cpu_ca8_proc_fin, cpu_v7_proc_fin
globl_equ cpu_ca8_reset, cpu_v7_reset
globl_equ cpu_ca8_do_idle, cpu_v7_do_idle
globl_equ cpu_ca8_dcache_clean_area, cpu_v7_dcache_clean_area
globl_equ cpu_ca8_set_pte_ext, cpu_v7_set_pte_ext
globl_equ cpu_ca8_suspend_size, cpu_v7_suspend_size
#ifdef CONFIG_ARM_CPU_SUSPEND
globl_equ cpu_ca8_do_suspend, cpu_v7_do_suspend
globl_equ cpu_ca8_do_resume, cpu_v7_do_resume
#endif
/*
* Cortex-A9 processor functions
*/
@ -451,7 +466,10 @@ __v7_setup_stack:
@ define struct processor (see <asm/proc-fns.h> and proc-macros.S)
define_processor_functions v7, dabort=v7_early_abort, pabort=v7_pabort, suspend=1
#ifndef CONFIG_ARM_LPAE
define_processor_functions ca8, dabort=v7_early_abort, pabort=v7_pabort, suspend=1
define_processor_functions ca9mp, dabort=v7_early_abort, pabort=v7_pabort, suspend=1
#endif
#ifdef CONFIG_CPU_PJ4B
define_processor_functions pj4b, dabort=v7_early_abort, pabort=v7_pabort, suspend=1
#endif
@ -507,6 +525,16 @@ __v7_ca9mp_proc_info:
__v7_proc __v7_ca9mp_proc_info, __v7_ca9mp_setup, proc_fns = ca9mp_processor_functions
.size __v7_ca9mp_proc_info, . - __v7_ca9mp_proc_info
/*
* ARM Ltd. Cortex A8 processor.
*/
.type __v7_ca8_proc_info, #object
__v7_ca8_proc_info:
.long 0x410fc080
.long 0xff0ffff0
__v7_proc __v7_ca8_proc_info, __v7_setup, proc_fns = ca8_processor_functions
.size __v7_ca8_proc_info, . - __v7_ca8_proc_info
#endif /* CONFIG_ARM_LPAE */
/*