]> git.baikalelectronics.ru Git - kernel.git/commit
crypto: ccp - Reduce maximum stack usage
authorArnd Bergmann <arnd@arndb.de>
Fri, 12 Jul 2019 08:59:24 +0000 (10:59 +0200)
committerHerbert Xu <herbert@gondor.apana.org.au>
Sat, 27 Jul 2019 11:08:31 +0000 (21:08 +1000)
commit89a1eeead1d1a29dd5691c1dc97cfe63fca4279b
tree15f94dbcdd961ed6ebd83dbec7d0a6ce99efb906
parentdae2db8d59b7b68344826ab256b5edeca1a66189
crypto: ccp - Reduce maximum stack usage

Each of the operations in ccp_run_cmd() needs several hundred
bytes of kernel stack. Depending on the inlining, these may
need separate stack slots that add up to more than the warning
limit, as shown in this clang based build:

drivers/crypto/ccp/ccp-ops.c:871:12: error: stack frame size of 1164 bytes in function 'ccp_run_aes_cmd' [-Werror,-Wframe-larger-than=]
static int ccp_run_aes_cmd(struct ccp_cmd_queue *cmd_q, struct ccp_cmd *cmd)

The problem may also happen when there is no warning, e.g. in the
ccp_run_cmd()->ccp_run_aes_cmd()->ccp_run_aes_gcm_cmd() call chain with
over 2000 bytes.

Mark each individual function as 'noinline_for_stack' to prevent
this from happening, and move the calls to the two special cases for aes
into the top-level function. This will keep the actual combined stack
usage to the mimimum: 828 bytes for ccp_run_aes_gcm_cmd() and
at most 524 bytes for each of the other cases.

Fixes: 14ae24991cb5 ("crypto: ccp - CCP device driver and interface support")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
drivers/crypto/ccp/ccp-ops.c