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dkim=pass header.d=gmail.com header.s=20210112 header.b=Vj+sNBSd; spf=pass (imf02.hostedemail.com: domain of ubizjak@gmail.com designates 209.85.128.180 as permitted sender) smtp.mailfrom=ubizjak@gmail.com; dmarc=pass (policy=none) header.from=gmail.com X-Stat-Signature: styydz4c5ehfoic3djgr18hrir1pyhuz X-Rspam-User: X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: A82CF80006 X-HE-Tag: 1667503433-700469 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Thu, Nov 3, 2022 at 8:09 PM Nathan Chancellor wrote: > > Hi Peter, > > On Sat, Oct 22, 2022 at 01:14:14PM +0200, Peter Zijlstra wrote: > > The use of set_64bit() in X86_64 only code is pretty pointless, seeing > > how it's a direct assignment. Remove all this nonsense. > > > > Additionally, since x86_64 unconditionally has HAVE_CMPXCHG_DOUBLE, > > there is no point in even having that fallback. > > > > Signed-off-by: Peter Zijlstra (Intel) > > --- > > arch/um/include/asm/pgtable-3level.h | 8 -------- > > arch/x86/include/asm/cmpxchg_64.h | 5 ----- > > drivers/iommu/intel/irq_remapping.c | 10 ++-------- > > 3 files changed, 2 insertions(+), 21 deletions(-) > > > > --- a/arch/um/include/asm/pgtable-3level.h > > +++ b/arch/um/include/asm/pgtable-3level.h > > @@ -58,11 +58,7 @@ > > #define pud_populate(mm, pud, pmd) \ > > set_pud(pud, __pud(_PAGE_TABLE + __pa(pmd))) > > > > -#ifdef CONFIG_64BIT > > -#define set_pud(pudptr, pudval) set_64bit((u64 *) (pudptr), pud_val(pudval)) > > -#else > > #define set_pud(pudptr, pudval) (*(pudptr) = (pudval)) > > -#endif > > > > static inline int pgd_newpage(pgd_t pgd) > > { > > @@ -71,11 +67,7 @@ static inline int pgd_newpage(pgd_t pgd) > > > > static inline void pgd_mkuptodate(pgd_t pgd) { pgd_val(pgd) &= ~_PAGE_NEWPAGE; } > > > > -#ifdef CONFIG_64BIT > > -#define set_pmd(pmdptr, pmdval) set_64bit((u64 *) (pmdptr), pmd_val(pmdval)) > > -#else > > #define set_pmd(pmdptr, pmdval) (*(pmdptr) = (pmdval)) > > -#endif > > > > static inline void pud_clear (pud_t *pud) > > { > > --- a/arch/x86/include/asm/cmpxchg_64.h > > +++ b/arch/x86/include/asm/cmpxchg_64.h > > @@ -2,11 +2,6 @@ > > #ifndef _ASM_X86_CMPXCHG_64_H > > #define _ASM_X86_CMPXCHG_64_H > > > > -static inline void set_64bit(volatile u64 *ptr, u64 val) > > -{ > > - *ptr = val; > > -} > > - > > #define arch_cmpxchg64(ptr, o, n) \ > > ({ \ > > BUILD_BUG_ON(sizeof(*(ptr)) != 8); \ > > --- a/drivers/iommu/intel/irq_remapping.c > > +++ b/drivers/iommu/intel/irq_remapping.c > > @@ -173,7 +173,6 @@ static int modify_irte(struct irq_2_iomm > > index = irq_iommu->irte_index + irq_iommu->sub_handle; > > irte = &iommu->ir_table->base[index]; > > > > -#if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) > > if ((irte->pst == 1) || (irte_modified->pst == 1)) { > > bool ret; > > > > @@ -187,11 +186,6 @@ static int modify_irte(struct irq_2_iomm > > * same as the old value. > > */ > > WARN_ON(!ret); > > - } else > > -#endif > > - { > > - set_64bit(&irte->low, irte_modified->low); > > - set_64bit(&irte->high, irte_modified->high); > > } > > __iommu_flush_cache(iommu, irte, sizeof(*irte)); It looks to me that the above part should not be removed, but set_64bit should be substituted with WRITE_ONCE. Only #if/#endif lines should be removed. Uros. > > > > @@ -249,8 +243,8 @@ static int clear_entries(struct irq_2_io > > end = start + (1 << irq_iommu->irte_mask); > > > > for (entry = start; entry < end; entry++) { > > - set_64bit(&entry->low, 0); > > - set_64bit(&entry->high, 0); > > + WRITE_ONCE(entry->low, 0); > > + WRITE_ONCE(entry->high, 0); > > } > > bitmap_release_region(iommu->ir_table->bitmap, index, > > irq_iommu->irte_mask); > > > > > > This commit is now in -next as commit 0475a2d10fc7 ("x86_64: Remove > pointless set_64bit() usage") and I just bisect a boot failure on my > Intel test desktop to it. > > # bad: [81214a573d19ae2fa5b528286ba23cd1cb17feec] Add linux-next specific files for 20221103 > # good: [8e5423e991e8cd0988d0c4a3f4ac4ca1af7d148a] Merge tag 'parisc-for-6.1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux > git bisect start '81214a573d19ae2fa5b528286ba23cd1cb17feec' '8e5423e991e8cd0988d0c4a3f4ac4ca1af7d148a' > # good: [8c13089d26d070fef87a64b48191cb7ae6dfbdb2] Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/cryptodev-2.6.git > git bisect good 8c13089d26d070fef87a64b48191cb7ae6dfbdb2 > # bad: [1bba8e9d15551d2f1c304d8f9d5c647a5b54bfc0] Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git > git bisect bad 1bba8e9d15551d2f1c304d8f9d5c647a5b54bfc0 > # good: [748c419c7ade509684ce5bcf74f50e13e0447afd] Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound.git > git bisect good 748c419c7ade509684ce5bcf74f50e13e0447afd > # good: [0acc81a3bf9f875c5ef03037ff5431d37f536f05] Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux.git > git bisect good 0acc81a3bf9f875c5ef03037ff5431d37f536f05 > # bad: [c0fb84e0698d2ce57f9391c7f4112f6e17676f99] Merge branch into tip/master: 'x86/cleanups' > git bisect bad c0fb84e0698d2ce57f9391c7f4112f6e17676f99 > # good: [7212c34aac1ec6abadf8b439824c8307ef0dd338] Merge branch 'x86/core' into x86/paravirt, to resolve conflicts > git bisect good 7212c34aac1ec6abadf8b439824c8307ef0dd338 > # good: [e1f2ac1d285d963a783a027a1b109420b07f30c1] Merge branch into tip/master: 'x86/cpu' > git bisect good e1f2ac1d285d963a783a027a1b109420b07f30c1 > # good: [306b75edbf25b86fe8189a4f96c217e49483f8ae] Merge branch into tip/master: 'x86/cleanups' > git bisect good 306b75edbf25b86fe8189a4f96c217e49483f8ae > # good: [8f28b415703e1935457a4bf0be7f03dc5471d09f] mm: Rename GUP_GET_PTE_LOW_HIGH > git bisect good 8f28b415703e1935457a4bf0be7f03dc5471d09f > # bad: [0475a2d10fc7ced3268cd0f0551390b5858f90cd] x86_64: Remove pointless set_64bit() usage > git bisect bad 0475a2d10fc7ced3268cd0f0551390b5858f90cd > # good: [a677802d5b0258f93f54620e1cd181b56547c36c] x86/mm/pae: Don't (ab)use atomic64 > git bisect good a677802d5b0258f93f54620e1cd181b56547c36c > # good: [533627610ae7709572a4fac1393fb61153e2a5b3] x86/mm/pae: Be consistent with pXXp_get_and_clear() > git bisect good 533627610ae7709572a4fac1393fb61153e2a5b3 > # first bad commit: [0475a2d10fc7ced3268cd0f0551390b5858f90cd] x86_64: Remove pointless set_64bit() usage > # good: [533627610ae7709572a4fac1393fb61153e2a5b3] x86/mm/pae: Be consistent with pXXp_get_and_clear() > git bisect good 533627610ae7709572a4fac1393fb61153e2a5b3 > # first bad commit: [0475a2d10fc7ced3268cd0f0551390b5858f90cd] x86_64: Remove pointless set_64bit() usage > > Unfortunately, I see no output on the screen it is attached to so I > assume it is happening pretty early during the boot sequence, which will > probably make getting logs somewhat hard. I can provide information > about the system if that would help reveal anything. If there is > anything I can test, I am more than happy to do so. > > Cheers, > Nathan