Re: [PATCH v6 5/7] cmd: rng: Use a statically allocated array for random bytes

On Mon, Jul 04, 2022 at 07:04:42PM +0530, Sughosh Ganu wrote:

Use a statically allocated buffer on stack instead of using malloc for reading the random bytes. Using a local array is faster than allocating heap memory on every initiation of the command.

Signed-off-by: Sughosh Ganu sughosh.ganu@linaro.org

Changes since V5: None

cmd/rng.c | 17 +++++++---------- 1 file changed, 7 insertions(+), 10 deletions(-)

diff --git a/cmd/rng.c b/cmd/rng.c index 2ddf27545f..81a23964b8 100644 --- a/cmd/rng.c +++ b/cmd/rng.c @@ -14,9 +14,9 @@ static int do_rng(struct cmd_tbl *cmdtp, int flag, int argc, char *const argv[]) { size_t n;

• struct udevice *dev;
• void *buf;

• u8 buf[64]; int devnum;

• struct udevice *dev; int ret = CMD_RET_SUCCESS;

  switch (argc) {

@@ -41,11 +41,10 @@ static int do_rng(struct cmd_tbl *cmdtp, int flag, int argc, char *const argv[]) return CMD_RET_FAILURE; }

• buf = malloc(n);
• if (!buf) {

• printf("Out of memory\n");
  

• return CMD_RET_FAILURE;
  

• }

• if (!n)

• return 0;
  

• n = min(n, sizeof(buf));

  if (dm_rng_read(dev, buf, n)) { printf("Reading RNG failed\n");

@@ -54,15 +53,13 @@ static int do_rng(struct cmd_tbl *cmdtp, int flag, int argc, char *const argv[]) print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, buf, n); }

• free(buf);
• return ret;

}

#ifdef CONFIG_SYS_LONGHELP static char rng_help_text[] = "[dev [n]]\n"

• " - print n random bytes read from dev\n";

• " - print n random bytes(max 64) read from dev\n";

#endif

U_BOOT_CMD(

2.25.1

Reviewed-by: Ilias Apalodimas ilias.apalodimas@linaro.org