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Message-ID: <CAMj1kXG_rRLU2Hp_GaZyayxx6J+HaWyPHPmE-hEZawuxzZ4JXw@mail.gmail.com>
Date: Wed, 31 Mar 2021 18:10:08 +0200
From: Ard Biesheuvel <ardb@...nel.org>
To: Daniel Walker <danielwa@...co.com>,
Arvind Sankar <nivedita@...m.mit.edu>
Cc: Will Deacon <will@...nel.org>,
Christophe Leroy <christophe.leroy@...roup.eu>,
ob Herring <robh@...nel.org>,
Daniel Gimpelevich <daniel@...pelevich.san-francisco.ca.us>,
Andrew Morton <akpm@...ux-foundation.org>,
X86 ML <x86@...nel.org>,
"open list:MIPS" <linux-mips@...r.kernel.org>,
"open list:LINUX FOR POWERPC (32-BIT AND 64-BIT)"
<linuxppc-dev@...ts.ozlabs.org>, xe-linux-external@...co.com,
linux-efi <linux-efi@...r.kernel.org>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 6/8] drivers: firmware: efi: libstub: enable generic commandline
(+ Arvind)
On Tue, 30 Mar 2021 at 19:57, Daniel Walker <danielwa@...co.com> wrote:
>
> This adds code to handle the generic command line changes.
> The efi code appears that it doesn't benefit as much from this design
> as it could.
>
> For example, if you had a prepend command line with "nokaslr" then
> you might be helpful to re-enable it in the boot loader or dts,
> but there appears to be no way to re-enable kaslr or some of the
> other options.
>
> Cc: xe-linux-external@...co.com
> Signed-off-by: Daniel Walker <danielwa@...co.com>
> ---
> .../firmware/efi/libstub/efi-stub-helper.c | 35 +++++++++++++++++++
> drivers/firmware/efi/libstub/efi-stub.c | 7 ++++
> drivers/firmware/efi/libstub/efistub.h | 1 +
> drivers/firmware/efi/libstub/x86-stub.c | 13 +++++--
> 4 files changed, 54 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/firmware/efi/libstub/efi-stub-helper.c b/drivers/firmware/efi/libstub/efi-stub-helper.c
> index aa8da0a49829..c155837cedc9 100644
> --- a/drivers/firmware/efi/libstub/efi-stub-helper.c
> +++ b/drivers/firmware/efi/libstub/efi-stub-helper.c
> @@ -13,6 +13,7 @@
> #include <linux/efi.h>
> #include <linux/kernel.h>
> #include <linux/printk.h> /* For CONSOLE_LOGLEVEL_* */
> +#include <linux/cmdline.h>
> #include <asm/efi.h>
> #include <asm/setup.h>
>
> @@ -172,6 +173,40 @@ int efi_printk(const char *fmt, ...)
> return printed;
> }
>
> +/**
> + * efi_handle_cmdline() - handle adding in building parts of the command line
> + * @cmdline: kernel command line
> + *
> + * Add in the generic parts of the commandline and start the parsing of the
> + * command line.
> + *
> + * Return: status code
> + */
> +efi_status_t efi_handle_cmdline(char const *cmdline)
> +{
> + efi_status_t status;
> +
> + status = efi_parse_options(CMDLINE_PREPEND);
> + if (status != EFI_SUCCESS) {
> + efi_err("Failed to parse options\n");
> + return status;
> + }
Even though I am not a fan of the 'success handling' pattern,
duplicating the exact same error handling three times is not great
either. Could we reuse more of the code here?
> +
> + status = efi_parse_options(IS_ENABLED(CONFIG_CMDLINE_OVERRIDE) ? "" : cmdline);
What is the point of calling efi_parse_options() with an empty string?
> + if (status != EFI_SUCCESS) {
> + efi_err("Failed to parse options\n");
> + return status;
> + }
> +
> + status = efi_parse_options(CMDLINE_APPEND);
> + if (status != EFI_SUCCESS) {
> + efi_err("Failed to parse options\n");
> + return status;
> + }
> +
> + return EFI_SUCCESS;
> +}
> +
> /**
> * efi_parse_options() - Parse EFI command line options
> * @cmdline: kernel command line
> diff --git a/drivers/firmware/efi/libstub/efi-stub.c b/drivers/firmware/efi/libstub/efi-stub.c
> index 26e69788f27a..760480248adf 100644
> --- a/drivers/firmware/efi/libstub/efi-stub.c
> +++ b/drivers/firmware/efi/libstub/efi-stub.c
> @@ -172,6 +172,12 @@ efi_status_t __efiapi efi_pe_entry(efi_handle_t handle,
> goto fail;
> }
>
> +#ifdef CONFIG_GENERIC_CMDLINE
> + status = efi_handle_cmdline(cmdline_ptr);
> + if (status != EFI_SUCCESS) {
> + goto fail_free_cmdline;
> + }
> +#else
> if (IS_ENABLED(CONFIG_CMDLINE_EXTEND) ||
> IS_ENABLED(CONFIG_CMDLINE_FORCE) ||
Does this mean CONFIG_GENERIC_CMDLINE does not replace CMDLINE_EXTEND
/ CMDLINE_FORCE etc, but introduces yet another variant on top of
those?
That does not seem like an improvement to me. I think it is great that
you are cleaning this up, but only if it means we can get rid of the
old implementation.
> cmdline_size == 0) {
> @@ -189,6 +195,7 @@ efi_status_t __efiapi efi_pe_entry(efi_handle_t handle,
> goto fail_free_cmdline;
> }
> }
> +#endif
>
> efi_info("Booting Linux Kernel...\n");
>
> diff --git a/drivers/firmware/efi/libstub/efistub.h b/drivers/firmware/efi/libstub/efistub.h
> index cde0a2ef507d..07c7f9fdfffc 100644
> --- a/drivers/firmware/efi/libstub/efistub.h
> +++ b/drivers/firmware/efi/libstub/efistub.h
> @@ -800,6 +800,7 @@ efi_status_t efi_relocate_kernel(unsigned long *image_addr,
> unsigned long alignment,
> unsigned long min_addr);
>
> +efi_status_t efi_handle_cmdline(char const *cmdline);
> efi_status_t efi_parse_options(char const *cmdline);
>
> void efi_parse_option_graphics(char *option);
> diff --git a/drivers/firmware/efi/libstub/x86-stub.c b/drivers/firmware/efi/libstub/x86-stub.c
> index f14c4ff5839f..30ad8fb7122d 100644
> --- a/drivers/firmware/efi/libstub/x86-stub.c
> +++ b/drivers/firmware/efi/libstub/x86-stub.c
> @@ -673,6 +673,8 @@ unsigned long efi_main(efi_handle_t handle,
> unsigned long bzimage_addr = (unsigned long)startup_32;
> unsigned long buffer_start, buffer_end;
> struct setup_header *hdr = &boot_params->hdr;
> + unsigned long cmdline_paddr = ((u64)hdr->cmd_line_ptr |
> + ((u64)boot_params->ext_cmd_line_ptr << 32));
> efi_status_t status;
>
> efi_system_table = sys_table_arg;
> @@ -735,6 +737,14 @@ unsigned long efi_main(efi_handle_t handle,
> image_offset = 0;
> }
>
> +#ifdef CONFIG_GENERIC_CMDLINE
> + status = efi_handle_cmdline((char *)cmdline_paddr);
> + if (status != EFI_SUCCESS) {
> + efi_err("Failed to parse options\n");
> + goto fail;
> + }
> +#else /* CONFIG_GENERIC_CMDLINE */
> +
> #ifdef CONFIG_CMDLINE_BOOL
> status = efi_parse_options(CONFIG_CMDLINE);
> if (status != EFI_SUCCESS) {
> @@ -743,8 +753,6 @@ unsigned long efi_main(efi_handle_t handle,
> }
> #endif
> if (!IS_ENABLED(CONFIG_CMDLINE_OVERRIDE)) {
> - unsigned long cmdline_paddr = ((u64)hdr->cmd_line_ptr |
> - ((u64)boot_params->ext_cmd_line_ptr << 32));
> status = efi_parse_options((char *)cmdline_paddr);
> if (status != EFI_SUCCESS) {
> efi_err("Failed to parse options\n");
> @@ -752,6 +760,7 @@ unsigned long efi_main(efi_handle_t handle,
> }
> }
>
> +#endif
> /*
> * At this point, an initrd may already have been loaded by the
> * bootloader and passed via bootparams. We permit an initrd loaded
> --
> 2.25.1
>
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