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From: Vineet Gupta <vgupta@kernel.org>
To: linux-snps-arc@lists.infradead.org
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	Anshuman Khandual <anshuman.khandual@arm.com>,
	Mike Rapoport <rppt@kernel.org>, Vineet Gupta <vgupta@kernel.org>
Subject: [PATCH 06/18] ARC: mm: Enable STRICT_MM_TYPECHECKS
Date: Tue, 10 Aug 2021 17:42:46 -0700	[thread overview]
Message-ID: <20210811004258.138075-7-vgupta@kernel.org> (raw)
In-Reply-To: <20210811004258.138075-1-vgupta@kernel.org>

In the past I've refrained from doing this (atleast 2 times) due to the
slight code bloat due to ABI implications of pte_t etc becoming sttuct

Per ARC ABI, functions return struct via memory and not through register
r0, even if the struct would fits in register(s)

 - caller allocates space on stack and passes the address as first arg
   (r0), shifting rest of args by one

 - callee creates return struct in memory (referenced via r0)

This time around the code actually shrunk slightly (due to subtle
inlining heuristic effects), but still slightly inefficient due to
return values passed through memory. That however seems like a small
cost compared to maintenance burden given the impending new mmu support
for page walk etc

Signed-off-by: Vineet Gupta <vgupta@kernel.org>
---
 arch/arc/include/asm/page.h | 26 --------------------------
 arch/arc/mm/ioremap.c       |  2 +-
 2 files changed, 1 insertion(+), 27 deletions(-)

diff --git a/arch/arc/include/asm/page.h b/arch/arc/include/asm/page.h
index 4a9d33372fe2..c4ac827379cd 100644
--- a/arch/arc/include/asm/page.h
+++ b/arch/arc/include/asm/page.h
@@ -34,12 +34,6 @@ void copy_user_highpage(struct page *to, struct page *from,
 			unsigned long u_vaddr, struct vm_area_struct *vma);
 void clear_user_page(void *to, unsigned long u_vaddr, struct page *page);
 
-#undef STRICT_MM_TYPECHECKS
-
-#ifdef STRICT_MM_TYPECHECKS
-/*
- * These are used to make use of C type-checking..
- */
 typedef struct {
 #ifdef CONFIG_ARC_HAS_PAE40
 	unsigned long long pte;
@@ -64,26 +58,6 @@ typedef struct {
 
 #define pte_pgprot(x) __pgprot(pte_val(x))
 
-#else /* !STRICT_MM_TYPECHECKS */
-
-#ifdef CONFIG_ARC_HAS_PAE40
-typedef unsigned long long pte_t;
-#else
-typedef unsigned long pte_t;
-#endif
-typedef unsigned long pgd_t;
-typedef unsigned long pgprot_t;
-
-#define pte_val(x)	(x)
-#define pgd_val(x)	(x)
-#define pgprot_val(x)	(x)
-#define __pte(x)	(x)
-#define __pgd(x)	(x)
-#define __pgprot(x)	(x)
-#define pte_pgprot(x)	(x)
-
-#endif
-
 typedef pte_t * pgtable_t;
 
 /*
diff --git a/arch/arc/mm/ioremap.c b/arch/arc/mm/ioremap.c
index 95c649fbc95a..052bbd8b1e5f 100644
--- a/arch/arc/mm/ioremap.c
+++ b/arch/arc/mm/ioremap.c
@@ -39,7 +39,7 @@ void __iomem *ioremap(phys_addr_t paddr, unsigned long size)
 	if (arc_uncached_addr_space(paddr))
 		return (void __iomem *)(u32)paddr;
 
-	return ioremap_prot(paddr, size, PAGE_KERNEL_NO_CACHE);
+	return ioremap_prot(paddr, size, pgprot_val(PAGE_KERNEL_NO_CACHE));
 }
 EXPORT_SYMBOL(ioremap);
 
-- 
2.25.1


  parent reply	other threads:[~2021-08-11  0:43 UTC|newest]

Thread overview: 37+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-11  0:42 [PATCH 00/18] ARC mm updates to support 3 or 4 levels of paging Vineet Gupta
2021-08-11  0:42 ` [PATCH 01/18] ARC: mm: simplify mmu scratch register assingment to mmu needs Vineet Gupta
2021-08-11  0:42 ` [PATCH 02/18] ARC: mm: remove tlb paranoid code Vineet Gupta
2021-08-11  0:42 ` [PATCH 03/18] ARC: mm: move mmu/cache externs out to setup.h Vineet Gupta
2021-08-11  5:10   ` Mike Rapoport
2021-08-11 18:46     ` Vineet Gupta
2021-08-11  0:42 ` [PATCH 04/18] ARC: mm: remove pgd_offset_fast Vineet Gupta
2021-08-11  5:12   ` Mike Rapoport
2021-08-11 18:54     ` Vineet Gupta
2021-08-11  0:42 ` [PATCH 05/18] ARC: mm: Fixes to allow STRICT_MM_TYPECHECKS Vineet Gupta
2021-08-11  0:42 ` Vineet Gupta [this message]
2021-08-11 12:04   ` [PATCH 06/18] ARC: mm: Enable STRICT_MM_TYPECHECKS Mike Rapoport
2021-08-11 19:01     ` Vineet Gupta
2021-08-11  0:42 ` [PATCH 07/18] ARC: ioremap: use more commonly used PAGE_KERNEL based uncached flag Vineet Gupta
2021-08-11  5:18   ` Mike Rapoport
2021-08-11 18:58     ` Vineet Gupta
2021-08-11  0:42 ` [PATCH 08/18] ARC: mm: pmd_populate* to use the canonical set_pmd (and drop pmd_set) Vineet Gupta
2021-08-11  0:42 ` [PATCH 09/18] ARC: mm: non-functional code cleanup ahead of 3 levels Vineet Gupta
2021-08-11 12:31   ` Mike Rapoport
2021-08-12  1:37     ` Vineet Gupta
2021-08-12  6:18       ` Mike Rapoport
2021-08-12 18:58         ` Vineet Gupta
2021-08-11  0:42 ` [PATCH 10/18] ARC: mm: move MMU specific bits out of ASID allocator Vineet Gupta
2021-08-11  0:42 ` [PATCH 11/18] ARC: mm: move MMU specific bits out of entry code Vineet Gupta
2021-08-11 12:15   ` Mike Rapoport
2021-08-11 19:30     ` Vineet Gupta
2021-08-11  0:42 ` [PATCH 12/18] ARC: mm: disintegrate mmu.h (arcv2 bits out) Vineet Gupta
2021-08-11  0:42 ` [PATCH 13/18] ARC: mm: disintegrate pgtable.h into levels and flags Vineet Gupta
2021-08-11  0:42 ` [PATCH 14/18] ARC: mm: hack to allow 2 level build with 4 level code Vineet Gupta
2021-08-11  0:42 ` [PATCH 15/18] ARC: mm: support 3 levels of page tables Vineet Gupta
2021-08-11 12:24   ` Mike Rapoport
2021-08-11 22:15     ` Vineet Gupta
2021-08-11  0:42 ` [PATCH 16/18] ARC: mm: support 4 " Vineet Gupta
2021-08-11 12:28   ` Mike Rapoport
2021-08-11 22:17     ` Vineet Gupta
2021-08-11  0:42 ` [PATCH 17/18] ARC: mm: vmalloc sync from kernel to user table to update PMD Vineet Gupta
2021-08-11  0:42 ` [PATCH 18/18] ARC: mm: introduce _PAGE_TABLE to explicitly link pgd,pud,pmd entries Vineet Gupta

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