From: Benjamin Gray <bgray@linux.ibm.com>
To: linuxppc-dev@lists.ozlabs.org
Cc: Benjamin Gray <bgray@linux.ibm.com>
Subject: [PATCH] powerpc/powermac: Use early_* IO variants in via_calibrate_decr
Date: Thu, 6 Jul 2023 11:08:16 +1000 [thread overview]
Message-ID: <20230706010816.72682-1-bgray@linux.ibm.com> (raw)
On a powermac platform, under the call path
start_kernel
time_init
ppc_md.calibrate_decr (pmac_calibrate_decr)
via_calibrate_decr
we run ioremap and iounmap. The unmap can enable interrupts
unexpectedly (cond_resched in vunmap_pmd_range), which is warned about
later in the boot sequence in start_kernel.
Use the early_* variants of these IO functions to prevent this.
The issue is pre-existing, but is surfaced by commit 721255b9826b
("genirq: Use a maple tree for interrupt descriptor management").
It's not clear to me why this causes it to surface.
Signed-off-by: Benjamin Gray <bgray@linux.ibm.com>
---
arch/powerpc/platforms/powermac/time.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/arch/powerpc/platforms/powermac/time.c b/arch/powerpc/platforms/powermac/time.c
index 4c5790aff1b5..8633891b7aa5 100644
--- a/arch/powerpc/platforms/powermac/time.c
+++ b/arch/powerpc/platforms/powermac/time.c
@@ -26,8 +26,8 @@
#include <linux/rtc.h>
#include <linux/of_address.h>
+#include <asm/early_ioremap.h>
#include <asm/sections.h>
-#include <asm/io.h>
#include <asm/machdep.h>
#include <asm/time.h>
#include <asm/nvram.h>
@@ -182,7 +182,7 @@ static int __init via_calibrate_decr(void)
return 0;
}
of_node_put(vias);
- via = ioremap(rsrc.start, resource_size(&rsrc));
+ via = early_ioremap(rsrc.start, resource_size(&rsrc));
if (via == NULL) {
printk(KERN_ERR "Failed to map VIA for timer calibration !\n");
return 0;
@@ -207,7 +207,7 @@ static int __init via_calibrate_decr(void)
ppc_tb_freq = (dstart - dend) * 100 / 6;
- iounmap(via);
+ early_iounmap((void *)via, resource_size(&rsrc));
return 1;
}
--
2.41.0
next reply other threads:[~2023-07-06 1:09 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-07-06 1:08 Benjamin Gray [this message]
2023-07-06 4:37 ` [PATCH] powerpc/powermac: Use early_* IO variants in via_calibrate_decr Christophe Leroy
2023-07-07 2:32 ` Benjamin Gray
2023-08-02 13:10 ` Michael Ellerman
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