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

[Tom Rini <trini@konsulko.com>]

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.
>  	 */
>  	/DISCARD/ : { *(.rel._secure*) }
> +#endif
>  	. = 0x00000000;
>  
>  	. = ALIGN(4);

Please update the big comment that you're now #if'ing around to explain
why the statement isn't true in some cases and hence the test, thanks!

-- 
Tom
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