Attachment 188440 Details for Bug 224008 – Save and Restore U-Boot registers.

[patch] Save and Restore U-Boot registers.

arm_ubldr.patch (text/plain), 1.48 KB, created by Duane on 2017-11-30 23:03:46 UTC

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Creator: Duane

Created: 2017-11-30 23:03:46 UTC

Size: 1.48 KB

patch

obsolete

>--- sys/boot/arm/uboot/start.S.orig	2017-11-30 17:56:42.838794000 +1100
>+++ sys/boot/arm/uboot/start.S	2017-12-01 09:42:37.028786000 +1100
>@@ -45,6 +45,10 @@
> 	orr	ip, ip, #(CPU_CONTROL_AFLT_ENABLE)
> 	mcr     p15, 0, ip, c1, c0, 0
> #endif
>+
>+	/* Save the arguments and return register before calling self_reloc */
>+	push	{r0, r1, r9, lr}
>+
> 	/* 
> 	 * Do self-relocation when the weak external symbol _DYNAMIC is non-NULL.
> 	 * When linked as a dynamic relocatable file, the linker automatically
>@@ -61,20 +65,31 @@
> 	addne	r1, r1, r0		/* r1 = dynamic section physaddr. */
> 	blne	_C_LABEL(self_reloc)	/* Do reloc if _DYNAMIC is non-NULL. */
> 
>+	/* Restore saved arguments */
>+	pop	{r0, r1, r9, lr}
>+
> 	/* Hint where to look for the API signature */
> 	ldr	ip, =uboot_address
> 	str	sp, [ip]
> 
>-	/* Save U-Boot's r8 and r9 */
>+	/* Save U-Boot's r8 and r9 for syscall trampoline */
> 	ldr	ip, =saved_regs
>-	str	r8, [ip, #0]
>-	str	r9, [ip, #4]
>+	str	r8, [ip, #0]		/* old gd pointer (use to hold lr) */
>+	str	r9, [ip, #4]		/* new gd pointer */
> 
> 	/* 
>-	 * Start loader.  This is basically a tail-recursion call; if main()
>-	 * returns, it returns to u-boot (which reports the value returned r0).
>+	 * Start loader.  Save return address first (r8 is available from
>+	 * trampoline save).
> 	 */
>-	b	main
>+	mov	r8, lr
>+	bl	main
>+	mov	lr, r8
>+
>+	/* Restore U-Boot environment */
>+	ldr	ip, =saved_regs
>+	ldr	r8, [ip, #0]
>+	ldr	r9, [ip, #4]
>+	mov	pc, lr
> 
> 	/* 
> 	 * Data for self-relocation, in the text segment for pc-rel access.

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Attachments on bug 224008: 188440