tree b93517c75a7521ee8149ac0b8c88b7eacb6786ca
parent a0d9a973a442c0dcad789d5e91ca3284d981923a
author Jayanth Dodderi Chidanand <jayanthdodderi.chidanand@arm.com> 1715104257 +0100
committer Jayanth Dodderi Chidanand <jayanthdodderi.chidanand@arm.com> 1724254527 +0100

refactor(cm): remove el1 context when SPMD_SPM_AT_SEL2=1

* Currently, EL1 context is included in cpu_context_t by default
  for all the build configurations.
  As part of the cpu context structure, we hold a copy of EL1, EL2
  system registers, per world per PE. This context structure is
  enormous and will continue to grow bigger with the addition of
  new features incorporating  new registers.

* Ideally, EL3 should save and restore the system registers at its next
  lower exception level, which is EL2 in majority of the configurations.

* This patch aims at optimising the memory allocation in cases, when
  the members from the context structure are unused. So el1 system
  register context must be omitted when lower EL is always x-EL2.

* "CTX_INCLUDE_EL2_REGS" is the internal build flag which gets set,
  when SPD=spmd and SPMD_SPM_AT_SEL2=1 or ENABLE_RME=1.
  It indicates, the system registers at EL2 are context switched for
  the respective build configuration. Here, there is no need  to save
  and restore EL1 system registers, while x-EL2 is enabled.

Henceforth, this patch addresses this issue, by taking out the EL1
context at all possible places, while EL2 (CTX_INCLUDE_EL2_REGS) is
enabled, there by saving memory.

Change-Id: Ifddc497d3c810e22a15b1c227a731bcc133c2f4a
Signed-off-by: Jayanth Dodderi Chidanand <jayanthdodderi.chidanand@arm.com>