@@ -146,22 +146,31 @@ In either case, the following conditions must be met:
corrupted by bogus network packets or disk data. This will save
you many hours of debug.
-- CPU register settings
+- Put the CPU(s) into the appropriate state.
+ On SMP systems, these requirements normally apply to all secondary
+ CPUs as well as the boot CPU. However, the exact requirements for
+ secondary CPUs may be platform-specific.
+
+ - CPU mode
+ All forms of interrupts must be disabled (IRQs and FIQs)
+ The CPU must be in SVC mode. (A special exception exists for Angel)
+
+ - Caches, MMUs
+ The MMU must be off.
+ Instruction cache may be on or off.
+ Data cache must be off.
+
+ - For SMP platforms, put the secondary CPUs in the appropriate state
+ (such as entering a wait loop). The exact requirements depend on
+ the platform code.
+
+- Boot CPU register settings
r0 = 0,
r1 = machine type number discovered in (3) above.
r2 = physical address of tagged list in system RAM, or
physical address of device tree block (dtb) in system RAM
-- CPU mode
- All forms of interrupts must be disabled (IRQs and FIQs)
- The CPU must be in SVC mode. (A special exception exists for Angel)
-
-- Caches, MMUs
- The MMU must be off.
- Instruction cache may be on or off.
- Data cache must be off.
-
-- The boot loader is expected to call the kernel image by jumping
+- Finally, the boot loader is expected to call the kernel image by jumping
directly to the first instruction of the kernel image.
On CPUs supporting the ARM instruction set, the entry must be
Currently, Booting doesn't say anything about booting on an SMP system. Although SMP boot varies somewhat from platform to platform, there are some general requirements which will usually apply. This patch documents those likely requirements, which should help to encourage some consistency between implementations. There's also some minor rearrangement of the text to restore a logical reading order after the other changes. Signed-off-by: Dave Martin <dave.martin@linaro.org> --- Documentation/arm/Booting | 31 ++++++++++++++++++++----------- 1 files changed, 20 insertions(+), 11 deletions(-)