On 27. 01. 25, 17:05, Uros Bizjak wrote:
This patch declares percpu variables in __seg_gs/__seg_fs named AS
and keeps them named AS qualified until they are dereferenced with
percpu accessor. This approach enables various compiler check
for cross-namespace variable assignments.
Signed-off-by: Uros Bizjak <[email protected]>
Acked-by: Nadav Amit <[email protected]>
Cc: Dennis Zhou <[email protected]>
Cc: Tejun Heo <[email protected]>
Cc: Christoph Lameter <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: "H. Peter Anvin" <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Brian Gerst <[email protected]>
Cc: Peter Zijlstra <[email protected]>
---
arch/x86/include/asm/percpu.h | 15 ++++++++++++---
1 file changed, 12 insertions(+), 3 deletions(-)
diff --git a/arch/x86/include/asm/percpu.h b/arch/x86/include/asm/percpu.h
index 27f668660abe..474d648bca9a 100644
--- a/arch/x86/include/asm/percpu.h
+++ b/arch/x86/include/asm/percpu.h
@@ -95,9 +95,18 @@
#endif /* CONFIG_SMP */
-#define __my_cpu_type(var) typeof(var) __percpu_seg_override
-#define __my_cpu_ptr(ptr) (__my_cpu_type(*(ptr))*)(__force uintptr_t)(ptr)
-#define __my_cpu_var(var) (*__my_cpu_ptr(&(var)))
+#if defined(CONFIG_USE_X86_SEG_SUPPORT) && defined(USE_TYPEOF_UNQUAL)
+# define __my_cpu_type(var) typeof(var)
+# define __my_cpu_ptr(ptr) (ptr)
+# define __my_cpu_var(var) (var)
+
+# define __percpu_qual __percpu_seg_override
+#else
+# define __my_cpu_type(var) typeof(var) __percpu_seg_override
+# define __my_cpu_ptr(ptr) (__my_cpu_type(*(ptr))*)(__force uintptr_t)(ptr)
+# define __my_cpu_var(var) (*__my_cpu_ptr(&(var)))
+#endif
+
Another issue with this is this causes all modules in 6.15 are 2-4 times
(compressed size) bigger:
$ ll /usr/lib/modules/*-[0-9]-default/kernel/drivers/atm/atmtcp.ko.zst
> -rw-r--r--. 1 root root 10325 May 13 11:49
/usr/lib/modules/6.14.6-2-default/kernel/drivers/atm/atmtcp.ko.zst
> -rw-r--r--. 1 root root 39677 Jun 2 09:13
/usr/lib/modules/6.15.0-1-default/kernel/drivers/atm/atmtcp.ko.zst
It's due to larger .BTF section:
.BTF PROGBITS 0000000000000000 [-00003080-]
[- 00000000000011a8-] {+00003100+}
{+ 0000000000012cf8+} 0000000000000000 0 0 1
There are a lot of new BTF types defined in each module like:
+attribute_group STRUCT
+backing_dev_info STRUCT
+bdi_writeback STRUCT
+bin_attribute STRUCT
+bio_end_io_t TYPEDEF
+bio_list STRUCT
+bio_set STRUCT
+bio STRUCT
+bio_vec STRUCT
Reverting this gives me back to normal sizes.
Any ideas?
FTR downstream report:
https://bugzilla.suse.com/show_bug.cgi?id=1244135
thanks,
--
js
suse labs
