From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mark Rutland Subject: Re: [PATCH] arm64/efi: efistub: jump to 'stext' directly, not through the header Date: Tue, 15 Jul 2014 12:31:38 +0100 Message-ID: <20140715113138.GZ26465@leverpostej> References: <1405415402-3427-1-git-send-email-ard.biesheuvel@linaro.org> <20140715095704.GV26465@leverpostej> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-efi-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Ard Biesheuvel Cc: "matt.fleming-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org" , "linux-efi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org" , "leif.lindholm-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org" , "msalter-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org" , "roy.franz-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org" , Catalin Marinas List-Id: linux-efi@vger.kernel.org > >> diff --git a/arch/arm64/kernel/efi-entry.S b/arch/arm64/kernel/efi-entry.S > >> index 619b1dd7bcde..6ef541731d9e 100644 > >> --- a/arch/arm64/kernel/efi-entry.S > >> +++ b/arch/arm64/kernel/efi-entry.S > >> @@ -61,7 +61,7 @@ ENTRY(efi_stub_entry) > >> */ > >> mov x20, x0 // DTB address > >> ldr x0, [sp, #16] // relocated _text address > >> - mov x21, x0 > >> + add x21, x0, #:lo12:stext_offset > > > > I think we can drop the :lo12: here, which will allow us to have a > > warning if stext_offset is unexpectedly large (I believe this will > > currently silently mask bits were that to happen?). > > > > There is no alternative lo12 relocation that errors out when the value > does not fit, so it would have to use a literal instead. Ah, that's a shame. What happens when the value doesn't fit if the linker / assembler don't error out? That sounds like a toolchain bug if they're silently doing the wrong thing. Cheers, Mark.