diff options
| author | Volodymyr Babchuk <vlad.babchuk@gmail.com> | 2018-09-03 20:18:49 +0300 |
|---|---|---|
| committer | Jérôme Forissier <jerome.forissier@linaro.org> | 2018-09-07 14:16:43 +0200 |
| commit | eecd6bd232cf55fe8c093d3336b696118a871fd1 (patch) | |
| tree | 716239089c016bd7793bb3ab01133819d1a682e1 | |
| parent | 81801f833a1f3af4cf098de75211eea5df924c51 (diff) | |
entry_std: use READ_ONCE in strategic places
Code that deals with command buffers follows rule
"read once, validate, use". Problem is that compiler
does not know about this rule, so it can optimize out
temporary variables and read data twice from the shared
buffer.
READ_ONCE() will ensure that compiler will not try to
optimize such reads.
Signed-off-by: Volodymyr Babchuk <vlad.babchuk@gmail.com>
Reviewed-by: Jens Wiklander <jens.wiklander@linaro.org>
| -rw-r--r-- | core/arch/arm/tee/entry_std.c | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/core/arch/arm/tee/entry_std.c b/core/arch/arm/tee/entry_std.c index 177d73c6..e91374e2 100644 --- a/core/arch/arm/tee/entry_std.c +++ b/core/arch/arm/tee/entry_std.c @@ -8,6 +8,7 @@ #include <bench.h> #include <compiler.h> #include <initcall.h> +#include <io.h> #include <kernel/linker.h> #include <kernel/msg_param.h> #include <kernel/panic.h> @@ -122,7 +123,7 @@ static TEE_Result copy_in_params(const struct optee_msg_param *params, for (n = 0; n < num_params; n++) { uint32_t attr; - saved_attr[n] = params[n].attr; + saved_attr[n] = READ_ONCE(params[n].attr); if (saved_attr[n] & OPTEE_MSG_ATTR_META) return TEE_ERROR_BAD_PARAMETERS; @@ -464,7 +465,7 @@ static struct mobj *map_cmd_buffer(paddr_t parg, uint32_t *num_params) return NULL; } - *num_params = arg->num_params; + *num_params = READ_ONCE(arg->num_params); args_size = OPTEE_MSG_GET_ARG_SIZE(*num_params); if (args_size > SMALL_PAGE_SIZE) { EMSG("Command buffer spans across page boundary"); @@ -484,7 +485,7 @@ static struct mobj *get_cmd_buffer(paddr_t parg, uint32_t *num_params) if (!arg) return NULL; - *num_params = arg->num_params; + *num_params = READ_ONCE(arg->num_params); args_size = OPTEE_MSG_GET_ARG_SIZE(*num_params); return mobj_shm_alloc(parg, args_size); |