| From 77a26516926577f1d2bae2ef92225ef9b62f80ed Mon Sep 17 00:00:00 2001 |
| From: Sasha Levin <sashal@kernel.org> |
| Date: Wed, 7 Apr 2021 14:30:48 -0700 |
| Subject: ACPI: CPPC: Replace cppc_attr with kobj_attribute |
| |
| From: Nathan Chancellor <nathan@kernel.org> |
| |
| [ Upstream commit 2bc6262c6117dd18106d5aa50d53e945b5d99c51 ] |
| |
| All of the CPPC sysfs show functions are called via indirect call in |
| kobj_attr_show(), where they should be of type |
| |
| ssize_t (*show)(struct kobject *kobj, struct kobj_attribute *attr, char *buf); |
| |
| because that is the type of the ->show() member in |
| 'struct kobj_attribute' but they are actually of type |
| |
| ssize_t (*show)(struct kobject *kobj, struct attribute *attr, char *buf); |
| |
| because of the ->show() member in 'struct cppc_attr', resulting in a |
| Control Flow Integrity violation [1]. |
| |
| $ cat /sys/devices/system/cpu/cpu0/acpi_cppc/highest_perf |
| 3400 |
| |
| $ dmesg | grep "CFI failure" |
| [ 175.970559] CFI failure (target: show_highest_perf+0x0/0x8): |
| |
| As far as I can tell, the only difference between 'struct cppc_attr' |
| and 'struct kobj_attribute' aside from the type of the attr parameter |
| is the type of the count parameter in the ->store() member (ssize_t vs. |
| size_t), which does not actually matter because all of these nodes are |
| read-only. |
| |
| Eliminate 'struct cppc_attr' in favor of 'struct kobj_attribute' to fix |
| the violation. |
| |
| [1]: https://lore.kernel.org/r/20210401233216.2540591-1-samitolvanen@google.com/ |
| |
| Fixes: 158c998ea44b ("ACPI / CPPC: add sysfs support to compute delivered performance") |
| Link: https://github.com/ClangBuiltLinux/linux/issues/1343 |
| Signed-off-by: Nathan Chancellor <nathan@kernel.org> |
| Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> |
| Signed-off-by: Sasha Levin <sashal@kernel.org> |
| --- |
| drivers/acpi/cppc_acpi.c | 14 +++----------- |
| 1 file changed, 3 insertions(+), 11 deletions(-) |
| |
| diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c |
| index 5c6ecbb66608..1b43f8ebfabe 100644 |
| --- a/drivers/acpi/cppc_acpi.c |
| +++ b/drivers/acpi/cppc_acpi.c |
| @@ -122,23 +122,15 @@ static DEFINE_PER_CPU(struct cpc_desc *, cpc_desc_ptr); |
| */ |
| #define NUM_RETRIES 500ULL |
| |
| -struct cppc_attr { |
| - struct attribute attr; |
| - ssize_t (*show)(struct kobject *kobj, |
| - struct attribute *attr, char *buf); |
| - ssize_t (*store)(struct kobject *kobj, |
| - struct attribute *attr, const char *c, ssize_t count); |
| -}; |
| - |
| #define define_one_cppc_ro(_name) \ |
| -static struct cppc_attr _name = \ |
| +static struct kobj_attribute _name = \ |
| __ATTR(_name, 0444, show_##_name, NULL) |
| |
| #define to_cpc_desc(a) container_of(a, struct cpc_desc, kobj) |
| |
| #define show_cppc_data(access_fn, struct_name, member_name) \ |
| static ssize_t show_##member_name(struct kobject *kobj, \ |
| - struct attribute *attr, char *buf) \ |
| + struct kobj_attribute *attr, char *buf) \ |
| { \ |
| struct cpc_desc *cpc_ptr = to_cpc_desc(kobj); \ |
| struct struct_name st_name = {0}; \ |
| @@ -164,7 +156,7 @@ show_cppc_data(cppc_get_perf_ctrs, cppc_perf_fb_ctrs, reference_perf); |
| show_cppc_data(cppc_get_perf_ctrs, cppc_perf_fb_ctrs, wraparound_time); |
| |
| static ssize_t show_feedback_ctrs(struct kobject *kobj, |
| - struct attribute *attr, char *buf) |
| + struct kobj_attribute *attr, char *buf) |
| { |
| struct cpc_desc *cpc_ptr = to_cpc_desc(kobj); |
| struct cppc_perf_fb_ctrs fb_ctrs = {0}; |
| -- |
| 2.30.2 |
| |