This is a note to let you know that I've just added the patch titled
powerpc/prom: Fix "ibm,arch-vec-5-platform-support" scan
to the 5.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
powerpc-prom-fix-ibm-arch-vec-5-platform-support-scan.patch
and it can be found in the queue-5.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From ed5b00a05c2ae95b59adc3442f45944ec632e794 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?C=C3=A9dric=20Le=20Goater?= <clg@xxxxxxxx>
Date: Fri, 22 Jan 2021 08:50:29 +0100
Subject: powerpc/prom: Fix "ibm,arch-vec-5-platform-support" scan
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From: Cédric Le Goater <clg@xxxxxxxx>
commit ed5b00a05c2ae95b59adc3442f45944ec632e794 upstream.
The "ibm,arch-vec-5-platform-support" property is a list of pairs of
bytes representing the options and values supported by the platform
firmware. At boot time, Linux scans this list and activates the
available features it recognizes : Radix and XIVE.
A recent change modified the number of entries to loop on and 8 bytes,
4 pairs of { options, values } entries are always scanned. This is
fine on KVM but not on PowerVM which can advertises less. As a
consequence on this platform, Linux reads extra entries pointing to
random data, interprets these as available features and tries to
activate them, leading to a firmware crash in
ibm,client-architecture-support.
Fix that by using the property length of "ibm,arch-vec-5-platform-support".
Fixes: ab91239942a9 ("powerpc/prom: Remove VLA in prom_check_platform_support()")
Cc: stable@xxxxxxxxxxxxxxx # v4.20+
Signed-off-by: Cédric Le Goater <clg@xxxxxxxx>
Reviewed-by: Fabiano Rosas <farosas@xxxxxxxxxxxxx>
Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20210122075029.797013-1-clg@xxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/powerpc/kernel/prom_init.c | 12 ++++--------
1 file changed, 4 insertions(+), 8 deletions(-)
--- a/arch/powerpc/kernel/prom_init.c
+++ b/arch/powerpc/kernel/prom_init.c
@@ -1305,14 +1305,10 @@ static void __init prom_check_platform_s
if (prop_len > sizeof(vec))
prom_printf("WARNING: ibm,arch-vec-5-platform-support longer than expected (len: %d)\n",
prop_len);
- prom_getprop(prom.chosen, "ibm,arch-vec-5-platform-support",
- &vec, sizeof(vec));
- for (i = 0; i < sizeof(vec); i += 2) {
- prom_debug("%d: index = 0x%x val = 0x%x\n", i / 2
- , vec[i]
- , vec[i + 1]);
- prom_parse_platform_support(vec[i], vec[i + 1],
- &supported);
+ prom_getprop(prom.chosen, "ibm,arch-vec-5-platform-support", &vec, sizeof(vec));
+ for (i = 0; i < prop_len; i += 2) {
+ prom_debug("%d: index = 0x%x val = 0x%x\n", i / 2, vec[i], vec[i + 1]);
+ prom_parse_platform_support(vec[i], vec[i + 1], &supported);
}
}
Patches currently in stable-queue which might be from clg@xxxxxxxx are
queue-5.4/kvm-ppc-make-the-vmx-instruction-emulation-routines-.patch
queue-5.4/powerpc-prom-fix-ibm-arch-vec-5-platform-support-scan.patch
