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From: Eric Farman <farman@linux.ibm.com>
To: Thomas Huth <thuth@redhat.com>, Cornelia Huck <cohuck@redhat.com>
Cc: Jason Herne <jjherne@linux.ibm.com>,
	Eric Farman <farman@linux.ibm.com>,
	Janosch Frank <frankja@linux.ibm.com>,
	Matthew Rosato <mjrosato@linux.ibm.com>,
	qemu-devel@nongnu.org,
	Christian Borntraeger <borntraeger@de.ibm.com>,
	qemu-s390x@nongnu.org, Jared Rossi <jrossi@linux.ibm.com>
Subject: [PATCH 2/2] pc-bios: s390x: Give precedence to reset PSW
Date: Thu, 19 Nov 2020 17:57:29 +0100	[thread overview]
Message-ID: <20201119165729.63351-3-farman@linux.ibm.com> (raw)
In-Reply-To: <20201119165729.63351-1-farman@linux.ibm.com>

Let's look at the Reset PSW first instead of the contents of memory.
It might be leftover from an earlier system boot when processing
a chreipl.

Signed-off-by: Eric Farman <farman@linux.ibm.com>
---
 pc-bios/s390-ccw/jump2ipl.c | 20 ++++++++++----------
 1 file changed, 10 insertions(+), 10 deletions(-)

diff --git a/pc-bios/s390-ccw/jump2ipl.c b/pc-bios/s390-ccw/jump2ipl.c
index fbae45b03c..67b4afb6a0 100644
--- a/pc-bios/s390-ccw/jump2ipl.c
+++ b/pc-bios/s390-ccw/jump2ipl.c
@@ -72,16 +72,6 @@ void jump_to_IPL_code(uint64_t address)
 
 void jump_to_low_kernel(void)
 {
-    /*
-     * If it looks like a Linux binary, i.e. there is the "S390EP" magic from
-     * arch/s390/kernel/head.S here, then let's jump to the well-known Linux
-     * kernel start address (when jumping to the PSW-at-zero address instead,
-     * the kernel startup code fails when we booted from a network device).
-     */
-    if (!memcmp((char *)0x10008, "S390EP", 6)) {
-        jump_to_IPL_code(KERN_IMAGE_START);
-    }
-
     /* Trying to get PSW at zero address */
     if (*((uint64_t *)0) & RESET_PSW_MASK) {
         /*
@@ -92,6 +82,16 @@ void jump_to_low_kernel(void)
         jump_to_IPL_code(0);
     }
 
+    /*
+     * If it looks like a Linux binary, i.e. there is the "S390EP" magic from
+     * arch/s390/kernel/head.S here, then let's jump to the well-known Linux
+     * kernel start address (when jumping to the PSW-at-zero address instead,
+     * the kernel startup code fails when we booted from a network device).
+     */
+    if (!memcmp((char *)0x10008, "S390EP", 6)) {
+        jump_to_IPL_code(KERN_IMAGE_START);
+    }
+
     /* No other option left, so use the Linux kernel start address */
     jump_to_IPL_code(KERN_IMAGE_START);
 }
-- 
2.17.1



  parent reply	other threads:[~2020-11-19 17:00 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-19 16:57 [PATCH 0/2] pc-bios/s390 fixes for reboot-to-vfio-ccw Eric Farman
2020-11-19 16:57 ` [PATCH 1/2] pc-bios: s390x: Ensure Read IPL memory is clean Eric Farman
2020-11-19 20:06   ` Thomas Huth
2020-11-20  8:26   ` Janosch Frank
2020-11-20 14:39     ` Eric Farman
2020-11-20  9:26   ` Cornelia Huck
2020-11-19 16:57 ` Eric Farman [this message]
2020-11-19 20:20   ` [PATCH 2/2] pc-bios: s390x: Give precedence to reset PSW Thomas Huth
2020-11-19 21:11     ` Eric Farman
2020-11-20  6:02       ` Thomas Huth
2020-11-20 14:38         ` Eric Farman
2020-11-19 17:52 ` [PATCH 0/2] pc-bios/s390 fixes for reboot-to-vfio-ccw Cornelia Huck

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