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| author | Florian Fainelli <f.fainelli@gmail.com> | 2015-01-09 21:34:43 +0300 |
|---|---|---|
| committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2015-04-02 12:06:35 +0300 |
| commit | e1e2f6e4c5759aab3a8cfb1a0c19017ea770dfd2 (patch) | |
| tree | 1943f678a84fa3369f3bfd3c805560a94b329ef1 /arch/arm/mm | |
| parent | 49f28aa6b0d0735dbe5f04263c49a199ed0c5bb7 (diff) | |
| download | linux-e1e2f6e4c5759aab3a8cfb1a0c19017ea770dfd2.tar.xz | |
ARM: 8276/1: Make CPU_DCACHE_DISABLE depend on !SMP
Enabling CPU_DCACHE_DISABLE on a SMP capable system will prevent the
kernel from booting because of the following ldrex instruction in
arch_spin_lock:
(gdb) x/10i $pc
=> 0xc053cfa8 <_raw_spin_lock+4>: ldrex r3, [r0]
0xc053cfac <_raw_spin_lock+8>: add r2, r3, #65536 ; 0x10000
which is taken by the very first printk call:
at /home/fainelli/work/linux/arch/arm/include/asm/spinlock.h:65
fmt=0xc0637650 " 01 66Booting Linux on physical CPU 0x%xn", args=<incomplete type>)
at kernel/printk/printk.c:1525
fmt=0xc05370f4 <printk+52> " 24320215342 04340235344 20320215342 36377/341 17") at kernel/printk/printk.c:1688
ldrex requires exclusive monitor(s) (local or global) which are no longer
working when the Data cache is disabled in CP15 and will just hang the CPU
there.
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'arch/arm/mm')
| -rw-r--r-- | arch/arm/mm/Kconfig | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/arm/mm/Kconfig b/arch/arm/mm/Kconfig index 9b4f29e595a4..133ecff6664e 100644 --- a/arch/arm/mm/Kconfig +++ b/arch/arm/mm/Kconfig @@ -738,7 +738,7 @@ config CPU_ICACHE_DISABLE config CPU_DCACHE_DISABLE bool "Disable D-Cache (C-bit)" - depends on CPU_CP15 + depends on CPU_CP15 && !SMP help Say Y here to disable the processor data cache. Unless you have a reason not to or are unsure, say N. |