| Message ID | 20200717111349.417688532@infradead.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Fixup page directory freeing | expand |
On Fri, Jul 17, 2020 at 01:10:06PM +0200, Peter Zijlstra wrote: > The first MMU_GATHER_TABLE_FREE user showed a logic error in the > tlb_needs_table_invalidate() definition. Make sure any TABLE_FREE has > it defined. Could you elaborate on the logic error, please? It's difficult to see through all of the #ifdefs, but afaict we #error if tlb_needs_table_invalidate() is defined but not CONFIG_MMU_GATHER_RCU_TABLE_FREE with and without this patch. In other words, I'm failing to see what this patch changes! > Fixes: 0d6e24d430ef ("asm-generic/tlb: provide MMU_GATHER_TABLE_FREE") > Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> > --- > include/asm-generic/tlb.h | 35 +++++++++++++++++++---------------- > 1 file changed, 19 insertions(+), 16 deletions(-) > > --- a/include/asm-generic/tlb.h > +++ b/include/asm-generic/tlb.h > @@ -172,6 +172,18 @@ > * various ptep_get_and_clear() functions. > */ > > +#ifndef CONFIG_MMU_GATHER_RCU_TABLE_FREE > + > +/* > + * Only RCU table free can override this; otherwise the TLBI is needed to > + * provide existence guarantees for software walkers. > + */ > +#ifdef tlb_needs_table_invalidate > +#error tlb_needs_table_invalidate() requires MMU_GATHER_RCU_TABLE_FREE > +#endif > + > +#endif /* CONFIG_MMU_GATHER_RCU_TABLE_FREE */ > + > #ifdef CONFIG_MMU_GATHER_TABLE_FREE > > struct mmu_table_batch { > @@ -187,17 +199,6 @@ struct mmu_table_batch { > > extern void tlb_remove_table(struct mmu_gather *tlb, void *table); > > -#else /* !CONFIG_MMU_GATHER_HAVE_TABLE_FREE */ > - > -/* > - * Without MMU_GATHER_TABLE_FREE the architecture is assumed to have page based > - * page directories and we can use the normal page batching to free them. > - */ > -#define tlb_remove_table(tlb, page) tlb_remove_page((tlb), (page)) > - > -#endif /* CONFIG_MMU_GATHER_TABLE_FREE */ > - > -#ifdef CONFIG_MMU_GATHER_RCU_TABLE_FREE > /* > * This allows an architecture that does not use the linux page-tables for > * hardware to skip the TLBI when freeing page tables. > @@ -206,13 +207,15 @@ extern void tlb_remove_table(struct mmu_ > #define tlb_needs_table_invalidate() (true) > #endif > > -#else > +#else /* !CONFIG_MMU_GATHER_HAVE_TABLE_FREE */ While you're at it, this comment can be fixed to refer to CONFIG_MMU_GATHER_RCU_TABLE_FREE. Will
--- a/include/asm-generic/tlb.h +++ b/include/asm-generic/tlb.h @@ -172,6 +172,18 @@ * various ptep_get_and_clear() functions. */ +#ifndef CONFIG_MMU_GATHER_RCU_TABLE_FREE + +/* + * Only RCU table free can override this; otherwise the TLBI is needed to + * provide existence guarantees for software walkers. + */ +#ifdef tlb_needs_table_invalidate +#error tlb_needs_table_invalidate() requires MMU_GATHER_RCU_TABLE_FREE +#endif + +#endif /* CONFIG_MMU_GATHER_RCU_TABLE_FREE */ + #ifdef CONFIG_MMU_GATHER_TABLE_FREE struct mmu_table_batch { @@ -187,17 +199,6 @@ struct mmu_table_batch { extern void tlb_remove_table(struct mmu_gather *tlb, void *table); -#else /* !CONFIG_MMU_GATHER_HAVE_TABLE_FREE */ - -/* - * Without MMU_GATHER_TABLE_FREE the architecture is assumed to have page based - * page directories and we can use the normal page batching to free them. - */ -#define tlb_remove_table(tlb, page) tlb_remove_page((tlb), (page)) - -#endif /* CONFIG_MMU_GATHER_TABLE_FREE */ - -#ifdef CONFIG_MMU_GATHER_RCU_TABLE_FREE /* * This allows an architecture that does not use the linux page-tables for * hardware to skip the TLBI when freeing page tables. @@ -206,13 +207,15 @@ extern void tlb_remove_table(struct mmu_ #define tlb_needs_table_invalidate() (true) #endif -#else +#else /* !CONFIG_MMU_GATHER_HAVE_TABLE_FREE */ -#ifdef tlb_needs_table_invalidate -#error tlb_needs_table_invalidate() requires MMU_GATHER_RCU_TABLE_FREE -#endif +/* + * Without MMU_GATHER_TABLE_FREE the architecture is assumed to have page based + * page directories and we can use the normal page batching to free them. + */ +#define tlb_remove_table(tlb, page) tlb_remove_page((tlb), (page)) -#endif /* CONFIG_MMU_GATHER_RCU_TABLE_FREE */ +#endif /* CONFIG_MMU_GATHER_TABLE_FREE */ #ifndef CONFIG_MMU_GATHER_NO_GATHER
The first MMU_GATHER_TABLE_FREE user showed a logic error in the tlb_needs_table_invalidate() definition. Make sure any TABLE_FREE has it defined. Fixes: 0d6e24d430ef ("asm-generic/tlb: provide MMU_GATHER_TABLE_FREE") Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> --- include/asm-generic/tlb.h | 35 +++++++++++++++++++---------------- 1 file changed, 19 insertions(+), 16 deletions(-)