This patch uses the reworked exception handling support to handle
runtime service requests through SMCs following the SMC calling
convention. This is a giant commit since all the changes are
inter-related. It does the following:
1. Replace the old exception handling mechanism with the new one
2. Enforce that SP_EL0 is used C runtime stacks.
3. Ensures that the cold and warm boot paths use the 'cpu_context'
structure to program an ERET into the next lower EL.
4. Ensures that SP_EL3 always points to the next 'cpu_context'
structure prior to an ERET into the next lower EL
5. Introduces a PSCI SMC handler which completes the use of PSCI as a
runtime service
Change-Id: I661797f834c0803d2c674d20f504df1b04c2b852
Co-authored-by: Achin Gupta <achin.gupta@arm.com>
This patch introduces the reworked exception handling logic which lays
the foundation for accessing runtime services in later patches. The
type of an exception has a greater say in the way it is
handled. SP_EL3 is used as the stack pointer for:
1. Determining the type of exception and handling the unexpected ones
on the exception stack
2. Saving and restoring the essential general purpose and system
register state after exception entry and prior to exception exit.
SP_EL0 is used as the stack pointer for handling runtime service
requests e.g. SMCs. A new structure for preserving general purpose
register state has been added to the 'cpu_context' structure. All
assembler ensures that it does not use callee saved registers
(x19-x29). The C runtime preserves them across functions calls. Hence
EL3 code does not have to save and restore them explicitly.
Since the exception handling framework has undergone substantial change,
the changes have been kept in separate files to aid readability. These
files will replace the existing ones in subsequent patches.
Change-Id: Ice418686592990ff7a4260771e8d6676e6c8c5ef
This patch introduces the framework to enable registration and
initialisation of runtime services. PSCI is registered and initialised
as a runtime service. Handling of runtime service requests will be
implemented in subsequent patches.
Change-Id: Id21e7ddc5a33d42b7d6e455b41155fc5441a9547
SPSR is a 32-bit register and so its size should be reflected in
the gp_regs structure. This patch fixes the type of gp_regs.spsr
to use a 32-bit variable. It also makes the size of the other
register fields more explicit.
Change-Id: I27e0367df1a91cc501d5217c1b3856d4097c60ba
This patch:
1. removes a duplicate assertion to check that the only error
condition that can be returned while turning a cpu off is
PSCI_E_DENIED. Having this assertion after calling
psci_afflvl_off() is sufficient.
2. corrects some incorrect usage of 'its' vs 'it is'
3. removes some unwanted white spaces
Change-Id: Icf014e269b54f5be5ce0b9fbe6b41258e4ebf403
The runtime exception handling assembler code used magic numbers for
saving and restoring the general purpose register context on stack
memory. The memory is interpreted as a 'gp_regs' structure and the
magic numbers are offsets to members of this structure. This patch
replaces the magic number offsets with constants. It also adds compile
time assertions to prevent an incorrect assembler view of this
structure.
Change-Id: Ibf125bfdd62ba3a33e58c5f1d71f8c229720781c
- Add instructions for contributing to ARM Trusted Firmware.
- Update copyright text in all files to acknowledge contributors.
Change-Id: I9311aac81b00c6c167d2f8c889aea403b84450e5
Jeenu Viswambharan
Achin Gupta
Dan Handley
Sandrine Bailleux