[U-Boot] [PATCH] ARM: Disable "DISCARD" for secure section if CONFIG_ARMV7_SECURE_BASE isn't defined

[Tom Rini <trini@konsulko.com>]

On Fri, Dec 11, 2015 at 10:15:03AM +0000, Dongsheng Wang wrote:
> Hi Tom,
> 
> Thanks for your review.
> 
> > On Thu, Dec 10, 2015 at 10:49:01AM +0800, Dongsheng Wang wrote:
> > 
> > > From: Wang Dongsheng <dongsheng.wang@nxp.com>
> > >
> > > Fix PSCI hang up without CONFIG_ARMV7_SECURE_BASE define.
> > > "DISCARD" will remove ._secure.text relocate, but PSCI framework has
> > > already used some absolute address those need to relocate.
> > >
> > > Use readelf -t -r u-boot show us:
> > > .__secure_start		addr: 601408e4
> > > .__secure_end		addr: 60141460
> > >
> > > 60141140  00000017 R_ARM_RELATIVE
> > > 46	_secure_monitor:
> > > 47	#ifdef CONFIG_ARMV7_PSCI
> > > 48      ldr     r5, =_psci_vectors
> > >
> > > 60141194  00000017 R_ARM_RELATIVE
> > > 6014119c  00000017 R_ARM_RELATIVE
> > > 601411a4  00000017 R_ARM_RELATIVE
> > > 601411ac  00000017 R_ARM_RELATIVE
> > > 64	_psci_table:
> > > 66	.word	psci_cpu_suspend
> > > ...
> > > 72	.word	psci_migrate
> > >
> > > 60141344  00000017 R_ARM_RELATIVE
> > > 6014145c  00000017 R_ARM_RELATIVE
> > > 202	ldr     r5, =psci_text_end
> > >
> > > Solutions:
> > > 1. Change absolute address to RelAdr.
> > >    Based on LDR (immediate, ARM), we only have 4K offset to jump.
> > > Now PSCI code size is close to 4K size that is LDR limit jump size, so
> > > even if the LDR is based on the current instruction address, there is
> > > also have a risk for RelAdr. If we use two jump steps I think we can
> > > fix this issue, but looks too hack, so give up this way.
> > >
> > > 2. Enable "DISCARD" only for CONFIG_ARMV7_SECURE_BASE has defined.
> > >    If CONFIG_ARMV7_SECURE_BASE is defined in platform, all of secure
> > > will in the BASE address that is absolute. psci_update_dt will
> > > relocate the PSCI code into link stage
> > > address(CONFIG_ARMV7_SECURE_BASE address), so using this method.
> > >
> > > Signed-off-by: Wang Dongsheng <dongsheng.wang@nxp.com>
> > > Reviewed-by: Peng Fan <Peng.Fan@nxp.com>
> > > Cc: Albert Aribaud <albert.u.boot@aribaud.net>
> > > Cc: Tom Warren <twarren@nvidia.com>
> > > Cc: York Sun <yorksun@freescale.com>
> > > Cc: Hans De Goede <hdegoede@redhat.com>
> > > Cc: Ian Campbell <ijc@hellion.org.uk>
> > > Cc: Tom Rini <trini@konsulko.com>
> > > Cc: Jan Kiszka <jan.kiszka@siemens.com>
> > > Cc: Stefano Babic <sbabic@denx.de>
> > >
> > > diff --git a/arch/arm/cpu/u-boot.lds b/arch/arm/cpu/u-boot.lds index
> > > d48a905..413d459 100644
> > > --- a/arch/arm/cpu/u-boot.lds
> > > +++ b/arch/arm/cpu/u-boot.lds
> > > @@ -14,6 +14,7 @@ OUTPUT_ARCH(arm)
> > >  ENTRY(_start)
> > >  SECTIONS
> > >  {
> > > +#if defined(CONFIG_ARMV7_SECURE_BASE) &&
> > defined(CONFIG_ARMV7_NONSEC)
> > >  	/*
> > >  	 * Discard the relocation entries for secure text.
> > >  	 * The secure code is bundled with u-boot image, so there will @@
> > > -31,6 +32,7 @@ SECTIONS
> > >  	 * avoid hole in the final image.
> > >  	 */
> 
> Update this comment, not my patch's comment, right?

Correct.

-- 
Tom
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