From: Ben Gras <ben@minix3.org>
Date: Mon, 24 Jun 2013 12:35:25 +0000 (+0200)
Subject: kernel: maintain stack alignment
X-Git-Tag: v3.3.0~902
X-Git-Url: http://zhaoyanbai.com/repos/Bv9ARM.ch02.html?a=commitdiff_plain;h=bb268230c4cbf2408e9f0f2d228e7e034c5d376b;p=minix.git

kernel: maintain stack alignment

	. 'fixes' 64-bit varargs (i.e. printf("%llu", ..)) argument
	  retrieval bug
---

diff --git a/kernel/arch/earm/mpx.S b/kernel/arch/earm/mpx.S
index 77b7d9d07..c86578e2c 100644
--- a/kernel/arch/earm/mpx.S
+++ b/kernel/arch/earm/mpx.S
@@ -130,6 +130,7 @@ irq_entry_from_user:
 	ldr	fp, [sp]
 
 	push	{fp}    /* save caller proc ptr */
+	sub	sp, sp, #4	/* maintain stack alignment */
 
 	/* stop user process cycles */
 	mov	r0, fp  /* first param: caller proc ptr */
@@ -139,6 +140,7 @@ irq_entry_from_user:
 	/* call handler */
 	bl	_C_LABEL(omap3_irq_handle)	/* omap3_irq_handle(void) */
 
+	add	sp, sp, #4
 	pop	{fp}    /* caller proc ptr */
 
 	/* data synchronization barrier */