On Wed, Apr 03, 2024 at 04:59:57PM -0500, Glenn Washburn wrote:
> On Fri, 15 Mar 2024 22:45:53 +0300
> "Vladimir 'phcoder' Serbinenko" <phco...@gmail.com> wrote:
>
> > With some coreboot configs setting a byte to a magic value
> > changes behaviour on next boot. Setting bit-by-bit is
> > possible but not convenient. Add cmosread and cmoswrite for
> > convenience.
> >
> > Signed-off-by: Vladimir Serbinenko <phco...@gmail.com>
> >
>
> Small nit, I think its customary to use '-s' in commands for setting
> variables. '-v' would intuitively be for verbosity. Also, it would be
I agree with Glenn.
> nice if you permanently configure your system to send patches as inline
> and not as attachments. Are you not using git-send?
I concur...
> From a29cfa77e292fdd0792eeb0bc2a0287524c1de1f Mon Sep 17 00:00:00 2001
> From: Vladimir Serbinenko <phco...@gmail.com>
> Date: Mon, 18 Sep 2023 02:20:13 +0200
> Subject: [PATCH] Add commands for reading and writing raw bytes to CMOS
>
> With some coreboot configs setting a byte to a magic value
> changes behaviour on next boot. Setting bit-by-bit is
> possible but not convenient. Add cmosread and cmoswrite for
> convenience.
>
> Signed-off-by: Vladimir Serbinenko <phco...@gmail.com>
> ---
> grub-core/commands/i386/cmostest.c | 77 +++++++++++++++++++++++++++++-
> 1 file changed, 76 insertions(+), 1 deletion(-)
>
> diff --git a/grub-core/commands/i386/cmostest.c
> b/grub-core/commands/i386/cmostest.c
> index 1f0c5341d..920cd81eb 100644
> --- a/grub-core/commands/i386/cmostest.c
> +++ b/grub-core/commands/i386/cmostest.c
> @@ -18,9 +18,12 @@
>
> #include <grub/dl.h>
> #include <grub/command.h>
> +#include <grub/extcmd.h>
> #include <grub/misc.h>
> #include <grub/cmos.h>
> #include <grub/i18n.h>
> +#include <grub/mm.h>
> +#include <grub/env.h>
>
> GRUB_MOD_LICENSE ("GPLv3+");
>
> @@ -99,7 +102,71 @@ grub_cmd_cmosset (struct grub_command *cmd __attribute__
> ((unused)),
> return grub_cmos_write (byte, value | (1 << bit));
> }
>
> -static grub_command_t cmd, cmd_clean, cmd_set;
> +static grub_err_t
> +grub_cmd_cmoswrite (struct grub_command *cmd __attribute__ ((unused)),
> + int argc, char *argv[])
> +{
> + int byte = -1, value = -1;
The byte and value should be defined as an unsigned long.
> +
> + if (argc != 2)
> + return grub_error (GRUB_ERR_BAD_ARGUMENT, N_("two arguments expected"));
> +
> + byte = grub_strtoul (argv[0], NULL, 0);
> + if (grub_errno)
In general I think we should not use shortened checks for enums and NULL.
Even if they work...
> + return grub_errno;
AFAICT the grub_errno is not reliable here. The good example how the
grub_strtoul() result should be checked is in the commit ac8a37dda
(net/http: Allow use of non-standard TCP/IP ports).
> + if (byte < 0 || byte >= 0x100)
> + return grub_error (GRUB_ERR_BAD_ARGUMENT, N_("invalid address"));
> +
> + value = grub_strtoul (argv[1], NULL, 0);
Ditto and below please...
> + if (grub_errno)
> + return grub_errno;
> +
> + if (value < 0 || value >= 0x100)
> + return grub_error (GRUB_ERR_BAD_ARGUMENT, N_("invalid value"));
> +
> + return grub_cmos_write (byte, value);
> +}
> +
> +static grub_err_t
> +grub_cmd_cmosread (grub_extcmd_context_t ctxt, int argc, char **argv)
Could you put this function before grub_cmd_cmoswrite()?
> +{
> + int byte = -1;
The byte should be defined as an unsigned long.
> + grub_uint8_t value = 0;
> + grub_err_t err;
> +
> + if (argc != 1)
> + return grub_error (GRUB_ERR_BAD_ARGUMENT, N_("one argument expected"));
> +
> + byte = grub_strtoul (argv[0], NULL, 0);
> + if (grub_errno)
> + return grub_errno;
> +
> + if (byte < 0 || byte >= 0x100)
> + return grub_error (GRUB_ERR_BAD_ARGUMENT, N_("invalid address"));
> +
> + err = grub_cmos_read (byte, &value);
> + if (err)
> + return err;
> +
> + if (ctxt->state[2].set) {
> + char buf[sizeof ("XX")];
I would prefer if this is defined at the top of the function.
> + grub_snprintf (buf, sizeof (buf), "%x", value);
> + grub_env_set(ctxt->state[2].arg, buf);
> + } else
> + grub_printf_("CMOS value at 0x%x is 0x%x\n", byte, value);
> + return GRUB_ERR_NONE;
> +}
> +
> +static const struct grub_arg_option read_options[] =
> + {
> + {0, 'v', 0, N_("Save read value into variable VARNAME."),
> + N_("VARNAME"), ARG_TYPE_STRING},
> + {0, 0, 0, 0, 0, 0}
> + };
> +
> +static grub_command_t cmd, cmd_clean, cmd_set, cmd_write;
> +static grub_extcmd_t cmd_read;
>
>
> GRUB_MOD_INIT(cmostest)
> @@ -114,6 +181,12 @@ GRUB_MOD_INIT(cmostest)
> N_("BYTE:BIT"),
> /* TRANSLATORS: A bit may be either set (1)
> or clear (0). */
> N_("Set bit at BYTE:BIT in CMOS."));
> + cmd_read = grub_register_extcmd_lockdown ("cmosread", grub_cmd_cmosread, 0,
> + N_("[-v VAR] ADDR"),
> + N_("Read CMOS byte at ADDR."),
> read_options);
> + cmd_write = grub_register_command_lockdown ("cmoswrite",
> grub_cmd_cmoswrite,
> + N_("ADDR VALUE"),
> + N_("Set CMOS byte at ADDR to
> VALUE."));
Please add commands descriptions to the GRUB documentation.
Daniel
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