diff options
| author | Andrew Donnellan <ajd@linux.ibm.com> | 2023-02-10 19:03:47 +1100 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2023-02-12 22:12:37 +1100 |
| commit | 6d64c497a31bd888110785def44529ebb96bce49 (patch) | |
| tree | 2d1ff52bfcfa5a284095d63d4f52972259f20b24 /arch/powerpc/kernel/secvar-sysfs.c | |
| parent | 50a466bf3e6f6f177dc0aeefa46a2f8927075a1d (diff) | |
powerpc/secvar: Warn when PAGE_SIZE is smaller than max object size
Due to sysfs constraints, when writing to a variable, we can only handle
writes of up to PAGE_SIZE.
It's possible that the maximum object size is larger than PAGE_SIZE, in
which case, print a warning on boot so that the user is aware.
Signed-off-by: Andrew Donnellan <ajd@linux.ibm.com>
Signed-off-by: Russell Currey <ruscur@russell.cc>
Reviewed-by: Stefan Berger <stefanb@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20230210080401.345462-13-ajd@linux.ibm.com
Diffstat (limited to 'arch/powerpc/kernel/secvar-sysfs.c')
| -rw-r--r-- | arch/powerpc/kernel/secvar-sysfs.c | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/secvar-sysfs.c b/arch/powerpc/kernel/secvar-sysfs.c index bfb19f22c6ba..6ba23b2bb9da 100644 --- a/arch/powerpc/kernel/secvar-sysfs.c +++ b/arch/powerpc/kernel/secvar-sysfs.c @@ -225,6 +225,7 @@ static int secvar_sysfs_load_static(void) static int secvar_sysfs_init(void) { + u64 max_size; int rc; if (!secvar_ops) { @@ -274,6 +275,14 @@ static int secvar_sysfs_init(void) goto err; } + // Due to sysfs limitations, we will only ever get a write buffer of + // up to 1 page in size. Print a warning if this is potentially going + // to cause problems, so that the user is aware. + secvar_ops->max_size(&max_size); + if (max_size > PAGE_SIZE) + pr_warn_ratelimited("PAGE_SIZE (%lu) is smaller than maximum object size (%llu), writes are limited to PAGE_SIZE\n", + PAGE_SIZE, max_size); + return 0; err: kobject_put(secvar_kobj); |