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| author | Vikram Kanigiri <vikram.kanigiri@arm.com> | 2016-01-20 15:57:35 +0000 |
|---|---|---|
| committer | Soby Mathew <soby.mathew@arm.com> | 2016-02-22 11:01:10 +0000 |
| commit | c64a04486ff469a826c01aa563a8988006a712ec (patch) | |
| tree | fe7c16aa2cc70180c2a0fd5e156fbded0c42fdae /docs | |
| parent | 85df7e44ce3974e2c78d99e6ea31f047de6de445 (diff) | |
Rationalise MMU and Page table related constants on ARM platforms
`board_arm_def.h` contains multiple definitions of
`PLAT_ARM_MMAP_ENTRIES` and `MAX_XLAT_TABLES` that are optimised for
memory usage depending upon the chosen build configuration. To ease
maintenance of these constants, this patch replaces their multiple
definitions with a single set of definitions that will work on all ARM
platforms.
Platforms can override the defaults with optimal values by enabling the
`ARM_BOARD_OPTIMISE_MMAP` build option. An example has been provided in
the Juno ADP port.
Additionally, `PLAT_ARM_MMAP_ENTRIES` is increased by one to accomodate
future ARM platforms.
Change-Id: I5ba6490fdd1e118cc9cc2d988ad7e9c38492b6f0
Diffstat (limited to 'docs')
| -rw-r--r-- | docs/user-guide.md | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/docs/user-guide.md b/docs/user-guide.md index 767fc42a..f01b8ff3 100644 --- a/docs/user-guide.md +++ b/docs/user-guide.md @@ -481,6 +481,13 @@ map is explained in the [Firmware Design]. match the frame used by the Non-Secure image (normally the Linux kernel). Default is true (access to the frame is allowed). +* `ARM_BOARD_OPTIMISE_MMAP`: Boolean option to enable or disable optimisation + of page table and MMU related macros `PLAT_ARM_MMAP_ENTRIES` and + `MAX_XLAT_TABLES`. By default this flag is 0, which means it uses the + default unoptimised values for these macros. ARM development platforms + that wish to optimise memory usage for page tables need to set this flag to 1 + and must override the related macros. + #### ARM CSS platform specific build options * `CSS_DETECT_PRE_1_7_0_SCP`: Boolean flag to detect SCP version |