| Message ID | 20180605113715.1133726-1-arnd@arndb.de |
|---|---|
| State | Accepted |
| Commit | 046c0dbec0238c25b7526c26c9a9687664229ce2 |
| Headers | show |
| Series | x86: mark native_set_p4d() as __always_inline | expand |
On Tue, Jun 05, 2018 at 11:35:15AM +0000, Arnd Bergmann wrote: > When CONFIG_OPTIMIZE_INLINING is enabled, the function native_set_p4d() > may not be fully inlined into the caller, resulting in a false-positive > warning about an access to the __pgtable_l5_enabled variable from a > non-__init function, despite the original caller being an __init function: > > WARNING: vmlinux.o(.text.unlikely+0x1429): Section mismatch in reference from the function native_set_p4d() to the variable .init.data:__pgtable_l5_enabled > WARNING: vmlinux.o(.text.unlikely+0x1429): Section mismatch in reference from the function native_p4d_clear() to the variable .init.data:__pgtable_l5_enabled > The function native_set_p4d() references > the variable __initdata __pgtable_l5_enabled. > This is often because native_set_p4d lacks a __initdata > annotation or the annotation of __pgtable_l5_enabled is wrong. > > Marking the native_set_p4d function and its caller native_p4d_clear() > avoids this problem. > > I did not bisect the original cause, but I assume this is related to > the recent rework that turned pgtable_l5_enabled() into an inline > function, which in turn caused the compiler to make different inlining > decisions. > > Fixes: ad3fe525b950 ("x86/mm: Unify pgtable_l5_enabled usage in early boot code") > Signed-off-by: Arnd Bergmann <arnd@arndb.de> Thanks for fixing this. Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Do you have a clue which native_set_p4d() call causes the issue? -- Kirill A. Shutemov
diff --git a/arch/x86/include/asm/pgtable_64.h b/arch/x86/include/asm/pgtable_64.h index 3c5385f9a88f..0fdcd21dadbd 100644 --- a/arch/x86/include/asm/pgtable_64.h +++ b/arch/x86/include/asm/pgtable_64.h @@ -216,7 +216,7 @@ static inline pgd_t pti_set_user_pgd(pgd_t *pgdp, pgd_t pgd) } #endif -static inline void native_set_p4d(p4d_t *p4dp, p4d_t p4d) +static __always_inline void native_set_p4d(p4d_t *p4dp, p4d_t p4d) { pgd_t pgd; @@ -230,7 +230,7 @@ static inline void native_set_p4d(p4d_t *p4dp, p4d_t p4d) *p4dp = native_make_p4d(native_pgd_val(pgd)); } -static inline void native_p4d_clear(p4d_t *p4d) +static __always_inline void native_p4d_clear(p4d_t *p4d) { native_set_p4d(p4d, native_make_p4d(0)); }
When CONFIG_OPTIMIZE_INLINING is enabled, the function native_set_p4d() may not be fully inlined into the caller, resulting in a false-positive warning about an access to the __pgtable_l5_enabled variable from a non-__init function, despite the original caller being an __init function: WARNING: vmlinux.o(.text.unlikely+0x1429): Section mismatch in reference from the function native_set_p4d() to the variable .init.data:__pgtable_l5_enabled WARNING: vmlinux.o(.text.unlikely+0x1429): Section mismatch in reference from the function native_p4d_clear() to the variable .init.data:__pgtable_l5_enabled The function native_set_p4d() references the variable __initdata __pgtable_l5_enabled. This is often because native_set_p4d lacks a __initdata annotation or the annotation of __pgtable_l5_enabled is wrong. Marking the native_set_p4d function and its caller native_p4d_clear() avoids this problem. I did not bisect the original cause, but I assume this is related to the recent rework that turned pgtable_l5_enabled() into an inline function, which in turn caused the compiler to make different inlining decisions. Fixes: ad3fe525b950 ("x86/mm: Unify pgtable_l5_enabled usage in early boot code") Signed-off-by: Arnd Bergmann <arnd@arndb.de> --- arch/x86/include/asm/pgtable_64.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) -- 2.9.0