From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 62CA9455626; Sat, 12 Sep 2026 12:38:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789216733; cv=none; b=tKAQ38N9E7DmjIlBH3OGGiQqM/yU3QIw33H4UlxeSnYMU5SmmIvcSZ60VE5zTQF5MDtRXVh9OW0UbtHQLBEbMxS0oPd0S10MnMVhHg9D+53Afuty095f1TZrSzXKDW0GZdKur3gXUUwr+tBlKMGAN0IeTzabQkltNqx0/q9RRok= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789216733; c=relaxed/simple; bh=yeu/sMj75u7rHtX8kEFoHrSWoCEwXPjjboC6BjVVOsw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=J+SusmO39VT4DDNgWhPD77B/75h6iO2Sq7btf+ZB+iUXTajRDcgtwYlXxEbTkaOJOV66N5SSvb6fW9xVCR8Hrnas+6RgKusPsep7PDoDRHiH4P5WsNiXPYoShTQPXuC4YWkP4eKifURp81tcIbWNYQ7sH4R+hNxIeONMHiWj/JY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=hqoEurvM; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="hqoEurvM" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 15FCC1F000FF; Sat, 12 Sep 2026 12:38:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789216731; bh=MsgHKwb9P2TIvHqBzUR1+9Mw6i20YxqypfyDZi3vpj4=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=hqoEurvMg3z9utUaWHT5xSqkY5lQfuK2SquaS3Q/twvDPBLwCjVC+9URK9QQOk8mS oeI7gQPh8Vg8L0op2LOcSeTupb2oC+zYTB8wOGh0sCfoqsxfzX62831R1BbVj5n+st Lwfj82Vnnpxpy4TYz1X8Fvse4C3RfeZqvrt8Wxms= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Muhammad Usama Anjum , Sasha Levin Subject: [PATCH 6.12 0797/1376] misc: sgi-gru: remove interrupt-context page-table walks Date: Sat, 12 Sep 2026 08:53:43 +0200 Message-ID: <20260912065625.297854987@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260912065607.535295758@linuxfoundation.org> References: <20260912065607.535295758@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Muhammad Usama Anjum [ Upstream commit 928a8e9f523df845fc496bcb9811013b67aabec5 ] The GRU TLB miss handler walks a process's page tables without holding page-table locks or a reference to the mapped page. It also uses a kernel page-table accessor on user page tables and supports only PMD-level large mappings on x86-64. Remove the direct walker. Send interrupt faults directly to user polling mode so the existing call-OS fallback retries them in process context. Remove the mmap-lock failure statistic that can no longer be incremented. Fixes: 142586409c8b ("GRU Driver: page faults & exceptions") Signed-off-by: Muhammad Usama Anjum Link: https://patch.msgid.link/20260730111316.3672672-2-usama.anjum@arm.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin --- drivers/misc/sgi-gru/grufault.c | 101 ++++--------------------------- drivers/misc/sgi-gru/gruprocfs.c | 1 - drivers/misc/sgi-gru/grutables.h | 1 - 3 files changed, 12 insertions(+), 91 deletions(-) diff --git a/drivers/misc/sgi-gru/grufault.c b/drivers/misc/sgi-gru/grufault.c index 3557d78ee47a2..5a87c12f444a3 100644 --- a/drivers/misc/sgi-gru/grufault.c +++ b/drivers/misc/sgi-gru/grufault.c @@ -166,13 +166,8 @@ static void get_clear_fault_map(struct gru_state *gru, } /* - * Atomic (interrupt context) & non-atomic (user context) functions to - * convert a vaddr into a physical address. The size of the page - * is returned in pageshift. - * returns: - * 0 - successful - * < 0 - error code - * 1 - (atomic only) try again in non-atomic context + * Convert a user virtual address to a physical address in process context. + * The size of the page is returned in pageshift. */ static int non_atomic_pte_lookup(struct vm_area_struct *vma, unsigned long vaddr, int write, @@ -192,87 +187,25 @@ static int non_atomic_pte_lookup(struct vm_area_struct *vma, return 0; } -/* - * atomic_pte_lookup - * - * Convert a user virtual address to a physical address - * Only supports Intel large pages (2MB only) on x86_64. - * ZZZ - hugepage support is incomplete - * - * NOTE: mmap_lock is already held on entry to this function. This - * guarantees existence of the page tables. - */ -static int atomic_pte_lookup(struct vm_area_struct *vma, unsigned long vaddr, - int write, unsigned long *paddr, int *pageshift) -{ - pgd_t *pgdp; - p4d_t *p4dp; - pud_t *pudp; - pmd_t *pmdp; - pte_t pte; - - pgdp = pgd_offset(vma->vm_mm, vaddr); - if (unlikely(pgd_none(*pgdp))) - goto err; - - p4dp = p4d_offset(pgdp, vaddr); - if (unlikely(p4d_none(*p4dp))) - goto err; - - pudp = pud_offset(p4dp, vaddr); - if (unlikely(pud_none(*pudp))) - goto err; - - pmdp = pmd_offset(pudp, vaddr); - if (unlikely(pmd_none(*pmdp))) - goto err; -#ifdef CONFIG_X86_64 - if (unlikely(pmd_leaf(*pmdp))) - pte = ptep_get((pte_t *)pmdp); - else -#endif - pte = *pte_offset_kernel(pmdp, vaddr); - - if (unlikely(!pte_present(pte) || - (write && (!pte_write(pte) || !pte_dirty(pte))))) - return 1; - - *paddr = pte_pfn(pte) << PAGE_SHIFT; -#ifdef CONFIG_HUGETLB_PAGE - *pageshift = is_vm_hugetlb_page(vma) ? HPAGE_SHIFT : PAGE_SHIFT; -#else - *pageshift = PAGE_SHIFT; -#endif - return 0; - -err: - return 1; -} - static int gru_vtop(struct gru_thread_state *gts, unsigned long vaddr, int write, int atomic, unsigned long *gpa, int *pageshift) { struct mm_struct *mm = gts->ts_mm; struct vm_area_struct *vma; unsigned long paddr; - int ret, ps; + int ps; vma = find_vma(mm, vaddr); if (!vma) goto inval; - /* - * Atomic lookup is faster & usually works even if called in non-atomic - * context. - */ - rmb(); /* Must/check ms_range_active before loading PTEs */ - ret = atomic_pte_lookup(vma, vaddr, write, &paddr, &ps); - if (ret) { - if (atomic) - goto upm; - if (non_atomic_pte_lookup(vma, vaddr, write, &paddr, &ps)) - goto inval; - } + if (atomic) + goto upm; + + /* Order the caller's ms_range_active check before loading PTEs. */ + rmb(); + if (non_atomic_pte_lookup(vma, vaddr, write, &paddr, &ps)) + goto inval; if (is_gru_paddr(paddr)) goto inval; paddr = paddr & ~((1UL << ps) - 1); @@ -569,19 +502,9 @@ static irqreturn_t gru_intr(int chiplet, int blade) continue; } - /* - * This is running in interrupt context. Trylock the mmap_lock. - * If it fails, retry the fault in user context. - */ + /* Address translation may sleep, so retry the fault in user context. */ gts->ustats.fmm_tlbmiss++; - if (!gts->ts_force_cch_reload && - mmap_read_trylock(gts->ts_mm)) { - gru_try_dropin(gru, gts, tfh, NULL); - mmap_read_unlock(gts->ts_mm); - } else { - tfh_user_polling_mode(tfh); - STAT(intr_mm_lock_failed); - } + tfh_user_polling_mode(tfh); } return IRQ_HANDLED; } diff --git a/drivers/misc/sgi-gru/gruprocfs.c b/drivers/misc/sgi-gru/gruprocfs.c index 97b8b38ab47df..b8139c27bc7f8 100644 --- a/drivers/misc/sgi-gru/gruprocfs.c +++ b/drivers/misc/sgi-gru/gruprocfs.c @@ -54,7 +54,6 @@ static int statistics_show(struct seq_file *s, void *p) printstat(s, intr_cbr); printstat(s, intr_tfh); printstat(s, intr_spurious); - printstat(s, intr_mm_lock_failed); printstat(s, call_os); printstat(s, call_os_wait_queue); printstat(s, user_flush_tlb); diff --git a/drivers/misc/sgi-gru/grutables.h b/drivers/misc/sgi-gru/grutables.h index 640daf1994df7..3348552925c61 100644 --- a/drivers/misc/sgi-gru/grutables.h +++ b/drivers/misc/sgi-gru/grutables.h @@ -182,7 +182,6 @@ struct gru_stats_s { atomic_long_t intr_cbr; atomic_long_t intr_tfh; atomic_long_t intr_spurious; - atomic_long_t intr_mm_lock_failed; atomic_long_t call_os; atomic_long_t call_os_wait_queue; atomic_long_t user_flush_tlb; -- 2.53.0