From mboxrd@z Thu Jan 1 00:00:00 1970 From: AKASHI Takahiro Date: Thu, 9 Aug 2018 17:30:49 +0900 Subject: [U-Boot] [RFC] efi_loader: workaround for EDK2's shell.efi In-Reply-To: References: <20180809061538.6624-1-takahiro.akashi@linaro.org> Message-ID: <20180809083048.GR11258@linaro.org> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de On Thu, Aug 09, 2018 at 07:55:06AM +0100, Alexander Graf wrote: > > > On 09.08.18 07:15, AKASHI Takahiro wrote: > > The commit 21b3edfc964 ("efi_loader: check parameters of CreateEvent") > > enforces a strict parameter check at CreateEvent(). Unfortunately, > > however, EDK2's Shell.efi calls this function with notify_tpl == 0. > > > > The patch above does right thing and we'd better fix the issue on EDK2 > > side, and yet we might want a workaround allowing for running un-modified > > version of EDK2 in short-term solution. > > ... of the EDK2 shell ... > > and it's not just about short term - we always want to be compatible :). Okay. > So what's the reason this does not trigger in edk2? Are they considering > TPL 0 a valid TPL always or did they just forget the check in create > event? If they always consider TPL 0 valid, we better change > is_valid_tpl to ensure compatibility with edk2's behavior. I'm not confident about what Shell's intent is. Created here is an event to be used to raise a signal for "notification of Ctrl-C keystrokes," and hence Shell expects such key data to always be sent to a task whatever its TPL is? > > The patch provides a minimum mitigation of parameter check. > > > > Signed-off-by: AKASHI Takahiro > > --- > > lib/efi_loader/efi_boottime.c | 3 ++- > > 1 file changed, 2 insertions(+), 1 deletion(-) > > > > diff --git a/lib/efi_loader/efi_boottime.c b/lib/efi_loader/efi_boottime.c > > index 2281703f261..e7a19c35415 100644 > > --- a/lib/efi_loader/efi_boottime.c > > +++ b/lib/efi_loader/efi_boottime.c > > @@ -627,7 +627,8 @@ efi_status_t efi_create_event(uint32_t type, efi_uintn_t notify_tpl, > > return EFI_INVALID_PARAMETER; > > } > > > > - if (is_valid_tpl(notify_tpl) != EFI_SUCCESS) > > + /* notify_tpl == 0: workaround for EDK2's Shell.efi */ > > That comment is too undescriptive. Better write something like "EDK2 > accepts TPL 0 in CreateEvent, so to ensure compatibility we should do > the same. EDK2 Shell.efi depends on this." Nice! Thanks, -Takahiro AKASHI > > Alex > > > + if (notify_tpl && (is_valid_tpl(notify_tpl) != EFI_SUCCESS)) > > return EFI_INVALID_PARAMETER; > > > > evt = calloc(1, sizeof(struct efi_event)); > >