The output buffer in test_ahash_speed will point to an address located
within the tcrypt module image.
This causes problems when trying to DMA map the buffer.
For e.g. on ARM-based LS1021A, a page fault occurs within the
DMA API when trying to access the struct page returned by
virt_to_page(output):

insmod tcrypt.ko mode=403

testing speed of async sha1 (sha1-caam)
test  0 (   16 byte blocks,   16 bytes per update,   1 updates):
Unable to handle kernel paging request at virtual address f07e9080
pgd = e58d0e00
[f07e9080] *pgd=80000080007003, *pmd=00000000
Internal error: Oops: 206 [#1] SMP THUMB2
Modules linked in: tcrypt(+)
CPU: 1 PID: 1119 Comm: insmod Not tainted 4.2.0-rc1-256134-gbf433416 #1
Hardware name: Freescale LS1021A
task: ea063900 ti: e5a34000 task.ti: e5a34000
PC is at dma_cache_maint_page+0x38/0xd0
LR is at __dma_page_cpu_to_dev+0x15/0x64
pc : [<800155a0>]    lr : [<8001564d>]    psr: 000f0033
sp : e5a35ca0  ip : 8063df00  fp : f07e9080
r10: 00000cd0  r9 : 8063df00  r8 : 805a2f04
r7 : 0017f804  r6 : 00000002  r5 : ee7f9000  r4 : 00000014
r3 : 80612d40  r2 : 01ff0080  r1 : 00000380  r0 : ee7f9000
Flags: nzcv  IRQs on  FIQs on  Mode SVC_32  ISA Thumb  Segment user
Control: 70c5387d  Table: e58d0e00  DAC: 9b7ede70
Process insmod (pid: 1119, stack limit = 0xe5a34210)
Stack: (0xe5a35ca0 to 0xe5a36000)
[...]
[<800155a0>] (dma_cache_maint_page) from [<8001564d>] (__dma_page_cpu_to_dev+0x15/0x64)
[<8001564d>] (__dma_page_cpu_to_dev) from [<800156eb>] (arm_dma_map_page+0x1f/0x44)
[<800156eb>] (arm_dma_map_page) from [<802935e3>] (ahash_digest+0x35f/0x510)
[<802935e3>] (ahash_digest) from [<7f800d03>] (test_ahash_speed.constprop.6+0x24a/0x4e4 [tcrypt])
[<7f800d03>] (test_ahash_speed.constprop.6 [tcrypt]) from [<7f802fd5>] (do_test+0x1898/0x2058 [tcrypt])
[<7f802fd5>] (do_test [tcrypt]) from [<7f80802f>] (tcrypt_mod_init+0x2e/0x63 [tcrypt])
[<7f80802f>] (tcrypt_mod_init [tcrypt]) from [<80009517>] (do_one_initcall+0xb3/0x134)
[<80009517>] (do_one_initcall) from [<80351ec7>] (do_init_module+0x3b/0x13c)
[<80351ec7>] (do_init_module) from [<8005cc3f>] (load_module+0x97b/0x9dc)
[<8005cc3f>] (load_module) from [<8005cd8d>] (SyS_finit_module+0x35/0x3e)
[<8005cd8d>] (SyS_finit_module) from [<8000d101>] (ret_fast_syscall+0x1/0x4c)
Code: 1aba 0152 eb00 0b02 (5882) 0f92

addr2line -f -i -e vmlinux 800155a0
page_zonenum
include/linux/mm.h:728
page_zone
include/linux/mm.h:881
dma_cache_maint_page
arch/arm/mm/dma-mapping.c:822
Signed-off-by: Horia Geant? <horia.geanta@freescale.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>