TBBR: Reduce size of hash buffers when possible
The TBBR implementation extracts hashes from certificates and stores
them in static buffers. TF-A supports 3 variants of SHA right now:
SHA-256, SHA-384 and SHA-512. When support for SHA-512 was added in
commit 9a3088a ("tbbr: Add build flag
HASH_ALG to let the user to select the SHA"), the hash buffers got
unconditionally increased from 51 to 83 bytes each. We can reduce that
space if we're using SHA-256 or SHA-384.

This saves some BSS space in both BL1 and BL2:
- BL1 with SHA-256: saving 168 bytes.
- BL1 with SHA-384: saving 80 bytes.
- BL2 with SHA-256: saving 384 bytes.
- BL2 with SHA-384: saving 192 bytes.

Change-Id: I0d02e5dc5f0162e82339c768609c9766cfe7e2bd
Signed-off-by: Sandrine Bailleux <sandrine.bailleux@arm.com>
1 parent 495599c commit 0b4e59211bf78db96b9f6a87869f623ea2810ebc
@Sandrine Bailleux Sandrine Bailleux authored on 17 Feb 2020
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