[PATCH AUTOSEL 6.4 09/10] powerpc/powermac: Use early_* IO variants in via_calibrate_decr()

From: Sasha Levin
Date: Tue Aug 22 2023 - 07:32:05 EST


From: Benjamin Gray <bgray@xxxxxxxxxxxxx>

[ Upstream commit 86582e6189dd8f9f52c25d46c70fe5d111da6345 ]

On a powermac platform, via the call path:

start_kernel()
time_init()
ppc_md.calibrate_decr() (pmac_calibrate_decr)
via_calibrate_decr()

ioremap() and iounmap() are called. The unmap can enable interrupts
unexpectedly (cond_resched() in vunmap_pmd_range()), which causes a
warning 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").

Signed-off-by: Benjamin Gray <bgray@xxxxxxxxxxxxx>
Reviewed-by: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Link: https://msgid.link/20230706010816.72682-1-bgray@xxxxxxxxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
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 4c5790aff1b54..8633891b7aa58 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;
}
--
2.40.1