[PATCH v8 0/8] tpm: rng: Move TPM RNG functionality to driver model
The TPM device provides the random number generator(RNG) functionality, whereby sending a command to the TPM device results in the TPM device responding with random bytes.
There was a discussion on the mailing list earlier[1], where it was explained that platforms with a TPM device can install the EFI_RNG_PROTOCOL for getting the random bytes instead of populating the dtb with the kaslr-seed property. That would make it possible to measure the dtb.
The TPM uclass driver adds the RNG child device as part of it's post_probe function.
Some additional changes have also been made to facilitate the use of the RNG devices, including extending the 'rng' command to take the RNG device as one of the command-line parameters.
This series depends on a patch[2] from Simon Glass for moving the TPM device version detection functions to the tpm_api.h header as static inline functions.
[1] - https://lore.kernel.org/u-boot/20220103120738.47835-1-ilias.apalodimas@linar... [2] - https://lore.kernel.org/u-boot/20220301001125.1554442-2-sjg@chromium.org/T/#...
Changes since V7: * Added a paragraph in the commit message highlighting the absence of the compatible string in the RNG driver, as suggested by Simon. * Rearranged the inclusion of headers as per the coding style guidelines, as suggested by Simon. * Use TPM_RNG_DRV_NAME for the RNG child name as suggested by Simon.
Ilias Apalodimas (1): efi_loader: initialize the RNG protocol after the TCC2
Simon Glass (1): tpm: Export the TPM-version functions
Sughosh Ganu (6): tpm: rng: Add driver model interface for TPM RNG device tpm: Add the RNG child device cmd: rng: Add support for selecting RNG device cmd: rng: Use a statically allocated array for random bytes doc: rng: Add documentation for the rng command test: rng: Add a UT testcase for the rng command
cmd/Kconfig | 1 + cmd/rng.c | 42 ++++++++++------ doc/usage/cmd/rng.rst | 26 ++++++++++ doc/usage/index.rst | 1 + drivers/rng/Kconfig | 9 ++++ drivers/rng/Makefile | 1 + drivers/rng/tpm_rng.c | 23 +++++++++ drivers/tpm/tpm-uclass.c | 40 +++++++++++++--- include/tpm_api.h | 10 ++++ lib/Kconfig | 1 + lib/efi_loader/efi_setup.c | 14 +++--- lib/tpm_api.c | 98 +++++++++++++++++--------------------- test/dm/rng.c | 29 +++++++++++ 13 files changed, 213 insertions(+), 82 deletions(-) create mode 100644 doc/usage/cmd/rng.rst create mode 100644 drivers/rng/tpm_rng.c
From: Simon Glass sjg@chromium.org
These functions should really be available outside the TPM code, so that other callers can find out which version the TPM is. Rename them to have a tpm_ prefix() and add them to the header file.
Signed-off-by: Simon Glass sjg@chromium.org Reviewed-by: Ilias Apalodimas ilias.apalodimas@linaro.org --- Changes since V7: None
include/tpm_api.h | 10 ++++++ lib/tpm_api.c | 92 +++++++++++++++++++++-------------------------- 2 files changed, 51 insertions(+), 51 deletions(-)
diff --git a/include/tpm_api.h b/include/tpm_api.h index ef45b43a8f..11aa14eb79 100644 --- a/include/tpm_api.h +++ b/include/tpm_api.h @@ -319,4 +319,14 @@ u32 tpm_write_lock(struct udevice *dev, u32 index); */ u32 tpm_resume(struct udevice *dev);
+static inline bool tpm_is_v1(struct udevice *dev) +{ + return IS_ENABLED(CONFIG_TPM_V1) && tpm_get_version(dev) == TPM_V1; +} + +static inline bool tpm_is_v2(struct udevice *dev) +{ + return IS_ENABLED(CONFIG_TPM_V2) && tpm_get_version(dev) == TPM_V2; +} + #endif /* __TPM_API_H */ diff --git a/lib/tpm_api.c b/lib/tpm_api.c index 4c662640a9..4ac4612c81 100644 --- a/lib/tpm_api.c +++ b/lib/tpm_api.c @@ -11,21 +11,11 @@ #include <tpm-v2.h> #include <tpm_api.h>
-static bool is_tpm1(struct udevice *dev) -{ - return IS_ENABLED(CONFIG_TPM_V1) && tpm_get_version(dev) == TPM_V1; -} - -static bool is_tpm2(struct udevice *dev) -{ - return IS_ENABLED(CONFIG_TPM_V2) && tpm_get_version(dev) == TPM_V2; -} - u32 tpm_startup(struct udevice *dev, enum tpm_startup_type mode) { - if (is_tpm1(dev)) { + if (tpm_is_v1(dev)) { return tpm1_startup(dev, mode); - } else if (is_tpm2(dev)) { + } else if (tpm_is_v2(dev)) { enum tpm2_startup_types type;
switch (mode) { @@ -47,9 +37,9 @@ u32 tpm_startup(struct udevice *dev, enum tpm_startup_type mode)
u32 tpm_resume(struct udevice *dev) { - if (is_tpm1(dev)) + if (tpm_is_v1(dev)) return tpm1_startup(dev, TPM_ST_STATE); - else if (is_tpm2(dev)) + else if (tpm_is_v2(dev)) return tpm2_startup(dev, TPM2_SU_STATE); else return -ENOSYS; @@ -57,9 +47,9 @@ u32 tpm_resume(struct udevice *dev)
u32 tpm_self_test_full(struct udevice *dev) { - if (is_tpm1(dev)) + if (tpm_is_v1(dev)) return tpm1_self_test_full(dev); - else if (is_tpm2(dev)) + else if (tpm_is_v2(dev)) return tpm2_self_test(dev, TPMI_YES); else return -ENOSYS; @@ -67,9 +57,9 @@ u32 tpm_self_test_full(struct udevice *dev)
u32 tpm_continue_self_test(struct udevice *dev) { - if (is_tpm1(dev)) + if (tpm_is_v1(dev)) return tpm1_continue_self_test(dev); - else if (is_tpm2(dev)) + else if (tpm_is_v2(dev)) return tpm2_self_test(dev, TPMI_NO); else return -ENOSYS; @@ -86,7 +76,7 @@ u32 tpm_clear_and_reenable(struct udevice *dev) return ret; }
- if (is_tpm1(dev)) { + if (tpm_is_v1(dev)) { ret = tpm1_physical_enable(dev); if (ret != TPM_SUCCESS) { log_err("TPM: Can't set enabled state\n"); @@ -105,9 +95,9 @@ u32 tpm_clear_and_reenable(struct udevice *dev)
u32 tpm_nv_enable_locking(struct udevice *dev) { - if (is_tpm1(dev)) + if (tpm_is_v1(dev)) return tpm1_nv_define_space(dev, TPM_NV_INDEX_LOCK, 0, 0); - else if (is_tpm2(dev)) + else if (tpm_is_v2(dev)) return -ENOSYS; else return -ENOSYS; @@ -115,9 +105,9 @@ u32 tpm_nv_enable_locking(struct udevice *dev)
u32 tpm_nv_read_value(struct udevice *dev, u32 index, void *data, u32 count) { - if (is_tpm1(dev)) + if (tpm_is_v1(dev)) return tpm1_nv_read_value(dev, index, data, count); - else if (is_tpm2(dev)) + else if (tpm_is_v2(dev)) return tpm2_nv_read_value(dev, index, data, count); else return -ENOSYS; @@ -126,9 +116,9 @@ u32 tpm_nv_read_value(struct udevice *dev, u32 index, void *data, u32 count) u32 tpm_nv_write_value(struct udevice *dev, u32 index, const void *data, u32 count) { - if (is_tpm1(dev)) + if (tpm_is_v1(dev)) return tpm1_nv_write_value(dev, index, data, count); - else if (is_tpm2(dev)) + else if (tpm_is_v2(dev)) return tpm2_nv_write_value(dev, index, data, count); else return -ENOSYS; @@ -141,9 +131,9 @@ u32 tpm_set_global_lock(struct udevice *dev)
u32 tpm_write_lock(struct udevice *dev, u32 index) { - if (is_tpm1(dev)) + if (tpm_is_v1(dev)) return -ENOSYS; - else if (is_tpm2(dev)) + else if (tpm_is_v2(dev)) return tpm2_write_lock(dev, index); else return -ENOSYS; @@ -152,9 +142,9 @@ u32 tpm_write_lock(struct udevice *dev, u32 index) u32 tpm_pcr_extend(struct udevice *dev, u32 index, const void *in_digest, void *out_digest) { - if (is_tpm1(dev)) + if (tpm_is_v1(dev)) return tpm1_extend(dev, index, in_digest, out_digest); - else if (is_tpm2(dev)) + else if (tpm_is_v2(dev)) return tpm2_pcr_extend(dev, index, TPM2_ALG_SHA256, in_digest, TPM2_DIGEST_LEN); else @@ -163,9 +153,9 @@ u32 tpm_pcr_extend(struct udevice *dev, u32 index, const void *in_digest,
u32 tpm_pcr_read(struct udevice *dev, u32 index, void *data, size_t count) { - if (is_tpm1(dev)) + if (tpm_is_v1(dev)) return tpm1_pcr_read(dev, index, data, count); - else if (is_tpm2(dev)) + else if (tpm_is_v2(dev)) return -ENOSYS; else return -ENOSYS; @@ -173,14 +163,14 @@ u32 tpm_pcr_read(struct udevice *dev, u32 index, void *data, size_t count)
u32 tpm_tsc_physical_presence(struct udevice *dev, u16 presence) { - if (is_tpm1(dev)) + if (tpm_is_v1(dev)) return tpm1_tsc_physical_presence(dev, presence);
/* * Nothing to do on TPM2 for this; use platform hierarchy availability * instead. */ - else if (is_tpm2(dev)) + else if (tpm_is_v2(dev)) return 0; else return -ENOSYS; @@ -188,11 +178,11 @@ u32 tpm_tsc_physical_presence(struct udevice *dev, u16 presence)
u32 tpm_finalise_physical_presence(struct udevice *dev) { - if (is_tpm1(dev)) + if (tpm_is_v1(dev)) return tpm1_finalise_physical_presence(dev);
/* Nothing needs to be done with tpm2 */ - else if (is_tpm2(dev)) + else if (tpm_is_v2(dev)) return 0; else return -ENOSYS; @@ -200,9 +190,9 @@ u32 tpm_finalise_physical_presence(struct udevice *dev)
u32 tpm_read_pubek(struct udevice *dev, void *data, size_t count) { - if (is_tpm1(dev)) + if (tpm_is_v1(dev)) return tpm1_read_pubek(dev, data, count); - else if (is_tpm2(dev)) + else if (tpm_is_v2(dev)) return -ENOSYS; /* not implemented yet */ else return -ENOSYS; @@ -210,9 +200,9 @@ u32 tpm_read_pubek(struct udevice *dev, void *data, size_t count)
u32 tpm_force_clear(struct udevice *dev) { - if (is_tpm1(dev)) + if (tpm_is_v1(dev)) return tpm1_force_clear(dev); - else if (is_tpm2(dev)) + else if (tpm_is_v2(dev)) return tpm2_clear(dev, TPM2_RH_PLATFORM, NULL, 0); else return -ENOSYS; @@ -220,11 +210,11 @@ u32 tpm_force_clear(struct udevice *dev)
u32 tpm_physical_enable(struct udevice *dev) { - if (is_tpm1(dev)) + if (tpm_is_v1(dev)) return tpm1_physical_enable(dev);
/* Nothing needs to be done with tpm2 */ - else if (is_tpm2(dev)) + else if (tpm_is_v2(dev)) return 0; else return -ENOSYS; @@ -232,11 +222,11 @@ u32 tpm_physical_enable(struct udevice *dev)
u32 tpm_physical_disable(struct udevice *dev) { - if (is_tpm1(dev)) + if (tpm_is_v1(dev)) return tpm1_physical_disable(dev);
/* Nothing needs to be done with tpm2 */ - else if (is_tpm2(dev)) + else if (tpm_is_v2(dev)) return 0; else return -ENOSYS; @@ -244,10 +234,10 @@ u32 tpm_physical_disable(struct udevice *dev)
u32 tpm_physical_set_deactivated(struct udevice *dev, u8 state) { - if (is_tpm1(dev)) + if (tpm_is_v1(dev)) return tpm1_physical_set_deactivated(dev, state); /* Nothing needs to be done with tpm2 */ - else if (is_tpm2(dev)) + else if (tpm_is_v2(dev)) return 0; else return -ENOSYS; @@ -256,9 +246,9 @@ u32 tpm_physical_set_deactivated(struct udevice *dev, u8 state) u32 tpm_get_capability(struct udevice *dev, u32 cap_area, u32 sub_cap, void *cap, size_t count) { - if (is_tpm1(dev)) + if (tpm_is_v1(dev)) return tpm1_get_capability(dev, cap_area, sub_cap, cap, count); - else if (is_tpm2(dev)) + else if (tpm_is_v2(dev)) return tpm2_get_capability(dev, cap_area, sub_cap, cap, count); else return -ENOSYS; @@ -266,9 +256,9 @@ u32 tpm_get_capability(struct udevice *dev, u32 cap_area, u32 sub_cap,
u32 tpm_get_permissions(struct udevice *dev, u32 index, u32 *perm) { - if (is_tpm1(dev)) + if (tpm_is_v1(dev)) return tpm1_get_permissions(dev, index, perm); - else if (is_tpm2(dev)) + else if (tpm_is_v2(dev)) return -ENOSYS; /* not implemented yet */ else return -ENOSYS; @@ -276,9 +266,9 @@ u32 tpm_get_permissions(struct udevice *dev, u32 index, u32 *perm)
u32 tpm_get_random(struct udevice *dev, void *data, u32 count) { - if (is_tpm1(dev)) + if (tpm_is_v1(dev)) return tpm1_get_random(dev, data, count); - else if (is_tpm2(dev)) + else if (tpm_is_v2(dev)) return -ENOSYS; /* not implemented yet */ else return -ENOSYS;
From: Ilias Apalodimas ilias.apalodimas@linaro.org
Due to U-Boot's lazy binding the RNG presented by the TCG is not available until the EFI_TCG2 protocol has been initialized. Since the TPM has a built-in RNG device we can use for the OS randomization, move the RNG protocol installation after the TCG.
Signed-off-by: Ilias Apalodimas ilias.apalodimas@linaro.org --- Changes since V7: New patch
lib/efi_loader/efi_setup.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-)
diff --git a/lib/efi_loader/efi_setup.c b/lib/efi_loader/efi_setup.c index 492ecf4cb1..751beda590 100644 --- a/lib/efi_loader/efi_setup.c +++ b/lib/efi_loader/efi_setup.c @@ -246,13 +246,6 @@ efi_status_t efi_init_obj_list(void) /* Set up console modes */ efi_setup_console_size();
- /* Install EFI_RNG_PROTOCOL */ - if (IS_ENABLED(CONFIG_EFI_RNG_PROTOCOL)) { - ret = efi_rng_register(); - if (ret != EFI_SUCCESS) - goto out; - } - /* Initialize variable services */ ret = efi_init_variables(); if (ret != EFI_SUCCESS) @@ -289,6 +282,13 @@ efi_status_t efi_init_obj_list(void) goto out; }
+ /* Install EFI_RNG_PROTOCOL */ + if (IS_ENABLED(CONFIG_EFI_RNG_PROTOCOL)) { + ret = efi_rng_register(); + if (ret != EFI_SUCCESS) + goto out; + } + if (IS_ENABLED(CONFIG_EFI_RISCV_BOOT_PROTOCOL)) { ret = efi_riscv_register(); if (ret != EFI_SUCCESS)
The TPM device has a builtin random number generator(RNG) functionality. Expose the RNG functions of the TPM device to the driver model so that they can be used by the EFI_RNG_PROTOCOL if the protocol is installed.
Also change the function arguments and return type of the random number functions to comply with the driver model api.
Signed-off-by: Sughosh Ganu sughosh.ganu@linaro.org Reviewed-by: Ilias Apalodimas ilias.apalodimas@linaro.org --- Changes since V7: None
drivers/rng/Kconfig | 9 +++++++++ drivers/rng/Makefile | 1 + drivers/rng/tpm_rng.c | 23 +++++++++++++++++++++++ lib/Kconfig | 1 + lib/tpm_api.c | 6 +++--- 5 files changed, 37 insertions(+), 3 deletions(-) create mode 100644 drivers/rng/tpm_rng.c
diff --git a/drivers/rng/Kconfig b/drivers/rng/Kconfig index 21a9ff0195..16143681da 100644 --- a/drivers/rng/Kconfig +++ b/drivers/rng/Kconfig @@ -74,4 +74,13 @@ config RNG_SMCCC_TRNG Enable random number generator for platforms that support Arm SMCCC TRNG interface.
+config TPM_RNG + bool "Enable random number generator on TPM device" + depends on TPM + default y + help + The TPM device has an inbuilt random number generator + functionality. Enable random number generator on TPM + devices. + endif diff --git a/drivers/rng/Makefile b/drivers/rng/Makefile index 2494717d7c..78f61051ac 100644 --- a/drivers/rng/Makefile +++ b/drivers/rng/Makefile @@ -13,3 +13,4 @@ obj-$(CONFIG_RNG_STM32MP1) += stm32mp1_rng.o obj-$(CONFIG_RNG_ROCKCHIP) += rockchip_rng.o obj-$(CONFIG_RNG_IPROC200) += iproc_rng200.o obj-$(CONFIG_RNG_SMCCC_TRNG) += smccc_trng.o +obj-$(CONFIG_TPM_RNG) += tpm_rng.o diff --git a/drivers/rng/tpm_rng.c b/drivers/rng/tpm_rng.c new file mode 100644 index 0000000000..1a5e9e2e4b --- /dev/null +++ b/drivers/rng/tpm_rng.c @@ -0,0 +1,23 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Copyright (c) 2022, Linaro Limited + */ + +#include <dm.h> +#include <rng.h> +#include <tpm_api.h> + +static int rng_tpm_random_read(struct udevice *dev, void *data, size_t count) +{ + return tpm_get_random(dev_get_parent(dev), data, count); +} + +static const struct dm_rng_ops tpm_rng_ops = { + .read = rng_tpm_random_read, +}; + +U_BOOT_DRIVER(tpm_rng) = { + .name = "tpm-rng", + .id = UCLASS_RNG, + .ops = &tpm_rng_ops, +}; diff --git a/lib/Kconfig b/lib/Kconfig index 7dd777b56a..e888c29245 100644 --- a/lib/Kconfig +++ b/lib/Kconfig @@ -360,6 +360,7 @@ source lib/crypt/Kconfig config TPM bool "Trusted Platform Module (TPM) Support" depends on DM + imply DM_RNG help This enables support for TPMs which can be used to provide security features for your board. The TPM can be connected via LPC or I2C diff --git a/lib/tpm_api.c b/lib/tpm_api.c index 4ac4612c81..032f383ca0 100644 --- a/lib/tpm_api.c +++ b/lib/tpm_api.c @@ -269,7 +269,7 @@ u32 tpm_get_random(struct udevice *dev, void *data, u32 count) if (tpm_is_v1(dev)) return tpm1_get_random(dev, data, count); else if (tpm_is_v2(dev)) - return -ENOSYS; /* not implemented yet */ - else - return -ENOSYS; + return tpm2_get_random(dev, data, count); + + return -ENOSYS; }
The TPM device comes with the random number generator(RNG) functionality which is built into the TPM device. Add logic to add the RNG child device in the TPM uclass post probe callback.
The RNG device can then be used to pass a set of random bytes to the linux kernel, need for address space randomisation through the EFI_RNG_PROTOCOL interface.
No compatible string is provided because this is not available in the binding defined by Linux. If multiple rand devices are in the system, then some method of selecting them (other than device tree) will need to be used, or a binding will need to be added.
Signed-off-by: Sughosh Ganu sughosh.ganu@linaro.org Reviewed-by: Ilias Apalodimas ilias.apalodimas@linaro.org --- Changes since V7: * Added a paragraph in the commit message highlighting the absence of the compatible string in the RNG driver, as suggested by Simon. * Rearranged the inclusion of headers as per the coding style guidelines, as suggested by Simon. * Use TPM_RNG_DRV_NAME for the RNG child name as suggested by Simon.
drivers/tpm/tpm-uclass.c | 40 ++++++++++++++++++++++++++++++++++------ 1 file changed, 34 insertions(+), 6 deletions(-)
diff --git a/drivers/tpm/tpm-uclass.c b/drivers/tpm/tpm-uclass.c index f67fe1019b..0eb35f50c4 100644 --- a/drivers/tpm/tpm-uclass.c +++ b/drivers/tpm/tpm-uclass.c @@ -9,12 +9,16 @@ #include <common.h> #include <dm.h> #include <log.h> -#include <linux/delay.h> -#include <linux/unaligned/be_byteshift.h> +#include <tpm_api.h> #include <tpm-v1.h> #include <tpm-v2.h> +#include <dm/lists.h> +#include <linux/delay.h> +#include <linux/unaligned/be_byteshift.h> #include "tpm_internal.h"
+#define TPM_RNG_DRV_NAME "tpm-rng" + int tpm_open(struct udevice *dev) { struct tpm_ops *ops = tpm_get_ops(dev); @@ -136,12 +140,36 @@ int tpm_xfer(struct udevice *dev, const uint8_t *sendbuf, size_t send_size, return 0; }
+static int tpm_uclass_post_probe(struct udevice *dev) +{ + int ret; + const char *drv = TPM_RNG_DRV_NAME; + struct udevice *child; + + if (CONFIG_IS_ENABLED(TPM_RNG)) { + ret = device_find_first_child_by_uclass(dev, UCLASS_RNG, + &child); + + if (ret != -ENODEV) { + log_debug("RNG child already added to the TPM device\n"); + return ret; + } + + ret = device_bind_driver(dev, drv, TPM_RNG_DRV_NAME, &child); + if (ret) + return log_msg_ret("bind", ret); + } + + return 0; +} + UCLASS_DRIVER(tpm) = { - .id = UCLASS_TPM, - .name = "tpm", - .flags = DM_UC_FLAG_SEQ_ALIAS, + .id = UCLASS_TPM, + .name = "tpm", + .flags = DM_UC_FLAG_SEQ_ALIAS, #if CONFIG_IS_ENABLED(OF_REAL) - .post_bind = dm_scan_fdt_dev, + .post_bind = dm_scan_fdt_dev, #endif + .post_probe = tpm_uclass_post_probe, .per_device_auto = sizeof(struct tpm_chip_priv), };
The 'rng' u-boot command is used for printing a select number of random bytes on the console. Currently, the RNG device from which the random bytes are read is fixed. However, a platform can have multiple RNG devices, one example being qemu, which has a virtio RNG device and the RNG pseudo device through the TPM chip.
Extend the 'rng' command so that the user can provide the RNG device number from which the random bytes are to be read. This will be the device index under the RNG uclass.
Signed-off-by: Sughosh Ganu sughosh.ganu@linaro.org Tested-by: Heinrich Schuchardt xypron.glpk@gmx.de Reviewed-by: Ilias Apalodimas ilias.apalodimas@linaro.org --- Changes since V7: None
cmd/rng.c | 31 +++++++++++++++++++++++-------- 1 file changed, 23 insertions(+), 8 deletions(-)
diff --git a/cmd/rng.c b/cmd/rng.c index 1ad5a096c0..2ddf27545f 100644 --- a/cmd/rng.c +++ b/cmd/rng.c @@ -13,19 +13,34 @@
static int do_rng(struct cmd_tbl *cmdtp, int flag, int argc, char *const argv[]) { - size_t n = 0x40; + size_t n; struct udevice *dev; void *buf; + int devnum; int ret = CMD_RET_SUCCESS;
- if (uclass_get_device(UCLASS_RNG, 0, &dev) || !dev) { + switch (argc) { + case 1: + devnum = 0; + n = 0x40; + break; + case 2: + devnum = hextoul(argv[1], NULL); + n = 0x40; + break; + case 3: + devnum = hextoul(argv[1], NULL); + n = hextoul(argv[2], NULL); + break; + default: + return CMD_RET_USAGE; + } + + if (uclass_get_device_by_seq(UCLASS_RNG, devnum, &dev) || !dev) { printf("No RNG device\n"); return CMD_RET_FAILURE; }
- if (argc >= 2) - n = hextoul(argv[1], NULL); - buf = malloc(n); if (!buf) { printf("Out of memory\n"); @@ -46,12 +61,12 @@ static int do_rng(struct cmd_tbl *cmdtp, int flag, int argc, char *const argv[])
#ifdef CONFIG_SYS_LONGHELP static char rng_help_text[] = - "[n]\n" - " - print n random bytes\n"; + "[dev [n]]\n" + " - print n random bytes read from dev\n"; #endif
U_BOOT_CMD( - rng, 2, 0, do_rng, + rng, 3, 0, do_rng, "print bytes from the hardware random number generator", rng_help_text );
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 Reviewed-by: Ilias Apalodimas ilias.apalodimas@linaro.org Reviewed-by: Simon Glass sjg@chromium.org --- Changes since V7: 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(
Add a usage document for the 'rng' u-boot command.
Signed-off-by: Sughosh Ganu sughosh.ganu@linaro.org Reviewed-by: Ilias Apalodimas ilias.apalodimas@linaro.org Reviewed-by: Simon Glass sjg@chromium.org --- Changes since V7: None
doc/usage/cmd/rng.rst | 26 ++++++++++++++++++++++++++ doc/usage/index.rst | 1 + 2 files changed, 27 insertions(+) create mode 100644 doc/usage/cmd/rng.rst
diff --git a/doc/usage/cmd/rng.rst b/doc/usage/cmd/rng.rst new file mode 100644 index 0000000000..1a352da41a --- /dev/null +++ b/doc/usage/cmd/rng.rst @@ -0,0 +1,26 @@ +.. SPDX-License-Identifier: GPL-2.0+ + +rng command +=========== + +Synopsis +-------- + +:: + + rng [devnum [n]] + +Description +----------- + +The *rng* command reads the random number generator(RNG) device and +prints the random bytes read on the console. A maximum of 64 bytes can +be read in one invocation of the command. + +devnum + The RNG device from which the random bytes are to be + read. Defaults to 0. + +n + Number of random bytes to be read and displayed on the + console. Default value is 0x40. Max value is 0x40. diff --git a/doc/usage/index.rst b/doc/usage/index.rst index 8b98629d6b..366c8bb4b0 100644 --- a/doc/usage/index.rst +++ b/doc/usage/index.rst @@ -55,6 +55,7 @@ Shell commands cmd/pstore cmd/qfw cmd/reset + cmd/rng cmd/sbi cmd/sf cmd/scp03
The 'rng' command dumps a number of random bytes on the console. Add a set of tests for the 'rng' command. The test function performs basic sanity testing of the command.
Since a unit test is being added for the command, enable it by default in the sandbox platforms.
Signed-off-by: Sughosh Ganu sughosh.ganu@linaro.org Reviewed-by: Simon Glass sjg@chromium.org Acked-by: Ilias Apalodimas ilias.apalodimas@linaro.org --- Changes since V7: None
cmd/Kconfig | 1 + test/dm/rng.c | 29 +++++++++++++++++++++++++++++ 2 files changed, 30 insertions(+)
diff --git a/cmd/Kconfig b/cmd/Kconfig index b3820f1e04..b4bf207a2d 100644 --- a/cmd/Kconfig +++ b/cmd/Kconfig @@ -1963,6 +1963,7 @@ config CMD_GETTIME config CMD_RNG bool "rng command" depends on DM_RNG + default y if SANDBOX select HEXDUMP help Print bytes from the hardware random number generator. diff --git a/test/dm/rng.c b/test/dm/rng.c index 5b34c93ed6..6d1f68848d 100644 --- a/test/dm/rng.c +++ b/test/dm/rng.c @@ -25,3 +25,32 @@ static int dm_test_rng_read(struct unit_test_state *uts) return 0; } DM_TEST(dm_test_rng_read, UT_TESTF_SCAN_PDATA | UT_TESTF_SCAN_FDT); + +/* Test the rng command */ +static int dm_test_rng_cmd(struct unit_test_state *uts) +{ + struct udevice *dev; + + ut_assertok(uclass_get_device(UCLASS_RNG, 0, &dev)); + ut_assertnonnull(dev); + + ut_assertok(console_record_reset_enable()); + + run_command("rng", 0); + ut_assert_nextlinen("00000000:"); + ut_assert_nextlinen("00000010:"); + ut_assert_nextlinen("00000020:"); + ut_assert_nextlinen("00000030:"); + ut_assert_console_end(); + + run_command("rng 0 10", 0); + ut_assert_nextlinen("00000000:"); + ut_assert_console_end(); + + run_command("rng 20", 0); + ut_assert_nextlinen("No RNG device"); + ut_assert_console_end(); + + return 0; +} +DM_TEST(dm_test_rng_cmd, UT_TESTF_SCAN_PDATA | UT_TESTF_SCAN_FDT | UT_TESTF_CONSOLE_REC);
participants (1)
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Sughosh Ganu