On 21 March 2017 at 11:58, Mark Rutland <mark.rutland@xxxxxxx> wrote: > On Mon, Mar 20, 2017 at 08:57:05PM +0000, Ard Biesheuvel wrote: >> The EFI stub currently prints a number of diagnostic messages that do >> not carry a lot of information. Since these prints are not controlled >> by 'loglevel' or other command line parameters, and since they appear on >> the EFI framebuffer as well (if enabled), it would be nice if we could >> turn them off. >> >> So let's only print them if 'efi=debug' is passed on the command line, >> or when CONFIG_DEBUG_EFI is set in the kernel build configuration. >> >> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx> >> --- >> drivers/firmware/efi/libstub/arm32-stub.c | 2 ++ >> drivers/firmware/efi/libstub/efi-stub-helper.c | 23 ++++++++++++++--------- >> drivers/firmware/efi/libstub/efistub.h | 9 +++++++++ >> drivers/firmware/efi/libstub/secureboot.c | 2 ++ >> include/linux/efi.h | 3 --- >> 5 files changed, 27 insertions(+), 12 deletions(-) > >> diff --git a/drivers/firmware/efi/libstub/efistub.h b/drivers/firmware/efi/libstub/efistub.h >> index 71c4d0e3c4ed..5ed16e6e166f 100644 >> --- a/drivers/firmware/efi/libstub/efistub.h >> +++ b/drivers/firmware/efi/libstub/efistub.h >> @@ -24,6 +24,15 @@ >> #define EFI_ALLOC_ALIGN EFI_PAGE_SIZE >> #endif >> >> +extern int __pure debug_enabled(void); >> + >> +#define pr_efi(sys_table, msg) do { \ >> + if (debug_enabled()) efi_printk(sys_table, "EFI stub: "msg); \ >> +} while (0) > > I was going to say that it's somewhat unfortunate to lose some of these > messages by default, but I guess this only adds one additional > round-trip when debugging a remote issue, and gives us the freedom to > add more comprehensive debug messages in future. > > Is the idea is to make the EFI stub completely silent in the successful > case, or is the aim just to minimise the number of messages? > > If it's only the latter, we could log a message regarding the existence > of efi=debug in the default case, which might help with bug reports. > > No strong feelings from me. > I guess we could simply look for 'quiet' instead, and invert the logic so we keep the current situation, but still allow for a pretty boot splash uncorrupted by meaningless printk's if we want to (and distros already use 'quiet' for exactly that purpose) -- To unsubscribe from this list: send the line "unsubscribe linux-efi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html