From: Mike Rapoport <rppt@kernel.org> To: "Russell King (Oracle)" <linux@armlinux.org.uk> Cc: Matthew Wilcox <willy@infradead.org>, Andrew Morton <akpm@linux-foundation.org>, Arnd Bergmann <arnd@arndb.de>, linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 15/14] arm: Rename PMD_ORDER to PMD_BITS Date: Mon, 4 Jul 2022 09:26:22 +0300 [thread overview] Message-ID: <YsKIDqAjg383vGuk@kernel.org> (raw) In-Reply-To: <YsJtYYsB/SinnNzI@shell.armlinux.org.uk> On Mon, Jul 04, 2022 at 05:32:33AM +0100, Russell King (Oracle) wrote: > On Sun, Jul 03, 2022 at 10:54:49PM +0100, Matthew Wilcox wrote: > > On Sun, Jul 03, 2022 at 10:16:45PM +0100, Russell King (Oracle) wrote: > > > On Sun, Jul 03, 2022 at 10:14:41PM +0100, Matthew Wilcox (Oracle) wrote: > > > > This is the number of bits used by a PMD entry, not the order of a PMD. > > > > > > No, it's not the number of bits. A PMD entry doesn't fit in 2 or 3 bits. > > > This is even more confusing. > > > > Well, what is it then? The order of something is PAGE_SIZE << n, and > > that doesn't seem to be what this is. > > Where is it defined that "order" means "PAGE_SIZE << n" ? > > "order" here is "order of magnitude" and in this case, it is 2^n, just > like order of magnitude in base 10 is 10^n. So strictly, the usage > here is completely correct, but if you describe "order" as "PAGE_SIZE << > n" that is no longer an order of magnitude, because it doesn't increase > in an order of magnitude (iow, n = 2 isn't PAGE_SIZE * PAGE_SIZE). I'd go with PMD_ENTRY_ORDER as Russell suggested last year. From 6389dfb2e5ae5b040ca1c8f07a071d8da2873b13 Mon Sep 17 00:00:00 2001 From: Mike Rapoport <rppt@linux.ibm.com> Date: Mon, 4 Jul 2022 09:17:40 +0300 Subject: [PATCH] ARM: head.S: rename PMD_ORDER to PMD_ENTRY_ORDER PMD_ORDER denotes order of magnitude for a PMD entry, i.e PMD entry size is 2 ^ PMD_ORDER. Rename PMD_ORDER to PMD_ENTRY_ORDER to allow a generic definition of PMD_ORDER as order of a PMD allocation: (PMD_SHIFT - PAGE_SHIFT). Signed-off-by: Mike Rapoport <rppt@linux.ibm.com> --- arch/arm/kernel/head.S | 34 +++++++++++++++++----------------- 1 file changed, 17 insertions(+), 17 deletions(-) diff --git a/arch/arm/kernel/head.S b/arch/arm/kernel/head.S index 500612d3da2e..29e2900178a1 100644 --- a/arch/arm/kernel/head.S +++ b/arch/arm/kernel/head.S @@ -38,10 +38,10 @@ #ifdef CONFIG_ARM_LPAE /* LPAE requires an additional page for the PGD */ #define PG_DIR_SIZE 0x5000 -#define PMD_ORDER 3 +#define PMD_ENTRY_ORDER 3 /* PMD entry size is 2^PMD_ENTRY_ORDER */ #else #define PG_DIR_SIZE 0x4000 -#define PMD_ORDER 2 +#define PMD_ENTRY_ORDER 2 #endif .globl swapper_pg_dir @@ -240,7 +240,7 @@ __create_page_tables: mov r6, r6, lsr #SECTION_SHIFT 1: orr r3, r7, r5, lsl #SECTION_SHIFT @ flags + kernel base - str r3, [r4, r5, lsl #PMD_ORDER] @ identity mapping + str r3, [r4, r5, lsl #PMD_ENTRY_ORDER] @ identity mapping cmp r5, r6 addlo r5, r5, #1 @ next section blo 1b @@ -250,7 +250,7 @@ __create_page_tables: * set two variables to indicate the physical start and end of the * kernel. */ - add r0, r4, #KERNEL_OFFSET >> (SECTION_SHIFT - PMD_ORDER) + add r0, r4, #KERNEL_OFFSET >> (SECTION_SHIFT - PMD_ENTRY_ORDER) ldr r6, =(_end - 1) adr_l r5, kernel_sec_start @ _pa(kernel_sec_start) #if defined CONFIG_CPU_ENDIAN_BE8 || defined CONFIG_CPU_ENDIAN_BE32 @@ -259,8 +259,8 @@ __create_page_tables: str r8, [r5] @ Save physical start of kernel (LE) #endif orr r3, r8, r7 @ Add the MMU flags - add r6, r4, r6, lsr #(SECTION_SHIFT - PMD_ORDER) -1: str r3, [r0], #1 << PMD_ORDER + add r6, r4, r6, lsr #(SECTION_SHIFT - PMD_ENTRY_ORDER) +1: str r3, [r0], #1 << PMD_ENTRY_ORDER add r3, r3, #1 << SECTION_SHIFT cmp r0, r6 bls 1b @@ -280,14 +280,14 @@ __create_page_tables: mov r3, pc mov r3, r3, lsr #SECTION_SHIFT orr r3, r7, r3, lsl #SECTION_SHIFT - add r0, r4, #(XIP_START & 0xff000000) >> (SECTION_SHIFT - PMD_ORDER) - str r3, [r0, #((XIP_START & 0x00f00000) >> SECTION_SHIFT) << PMD_ORDER]! + add r0, r4, #(XIP_START & 0xff000000) >> (SECTION_SHIFT - PMD_ENTRY_ORDER) + str r3, [r0, #((XIP_START & 0x00f00000) >> SECTION_SHIFT) << PMD_ENTRY_ORDER]! ldr r6, =(_edata_loc - 1) - add r0, r0, #1 << PMD_ORDER - add r6, r4, r6, lsr #(SECTION_SHIFT - PMD_ORDER) + add r0, r0, #1 << PMD_ENTRY_ORDER + add r6, r4, r6, lsr #(SECTION_SHIFT - PMD_ENTRY_ORDER) 1: cmp r0, r6 add r3, r3, #1 << SECTION_SHIFT - strls r3, [r0], #1 << PMD_ORDER + strls r3, [r0], #1 << PMD_ENTRY_ORDER bls 1b #endif @@ -297,10 +297,10 @@ __create_page_tables: */ mov r0, r2, lsr #SECTION_SHIFT cmp r2, #0 - ldrne r3, =FDT_FIXED_BASE >> (SECTION_SHIFT - PMD_ORDER) + ldrne r3, =FDT_FIXED_BASE >> (SECTION_SHIFT - PMD_ENTRY_ORDER) addne r3, r3, r4 orrne r6, r7, r0, lsl #SECTION_SHIFT - strne r6, [r3], #1 << PMD_ORDER + strne r6, [r3], #1 << PMD_ENTRY_ORDER addne r6, r6, #1 << SECTION_SHIFT strne r6, [r3] @@ -319,7 +319,7 @@ __create_page_tables: addruart r7, r3, r0 mov r3, r3, lsr #SECTION_SHIFT - mov r3, r3, lsl #PMD_ORDER + mov r3, r3, lsl #PMD_ENTRY_ORDER add r0, r4, r3 mov r3, r7, lsr #SECTION_SHIFT @@ -349,7 +349,7 @@ __create_page_tables: * If we're using the NetWinder or CATS, we also need to map * in the 16550-type serial port for the debug messages */ - add r0, r4, #0xff000000 >> (SECTION_SHIFT - PMD_ORDER) + add r0, r4, #0xff000000 >> (SECTION_SHIFT - PMD_ENTRY_ORDER) orr r3, r7, #0x7c000000 str r3, [r0] #endif @@ -359,10 +359,10 @@ __create_page_tables: * Similar reasons here - for debug. This is * only for Acorn RiscPC architectures. */ - add r0, r4, #0x02000000 >> (SECTION_SHIFT - PMD_ORDER) + add r0, r4, #0x02000000 >> (SECTION_SHIFT - PMD_ENTRY_ORDER) orr r3, r7, #0x02000000 str r3, [r0] - add r0, r4, #0xd8000000 >> (SECTION_SHIFT - PMD_ORDER) + add r0, r4, #0xd8000000 >> (SECTION_SHIFT - PMD_ENTRY_ORDER) str r3, [r0] #endif #endif -- 2.34.1 -- Sincerely yours, Mike.
WARNING: multiple messages have this Message-ID (diff)
From: Mike Rapoport <rppt@kernel.org> To: "Russell King (Oracle)" <linux@armlinux.org.uk> Cc: Matthew Wilcox <willy@infradead.org>, Andrew Morton <akpm@linux-foundation.org>, Arnd Bergmann <arnd@arndb.de>, linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 15/14] arm: Rename PMD_ORDER to PMD_BITS Date: Mon, 4 Jul 2022 09:26:22 +0300 [thread overview] Message-ID: <YsKIDqAjg383vGuk@kernel.org> (raw) In-Reply-To: <YsJtYYsB/SinnNzI@shell.armlinux.org.uk> On Mon, Jul 04, 2022 at 05:32:33AM +0100, Russell King (Oracle) wrote: > On Sun, Jul 03, 2022 at 10:54:49PM +0100, Matthew Wilcox wrote: > > On Sun, Jul 03, 2022 at 10:16:45PM +0100, Russell King (Oracle) wrote: > > > On Sun, Jul 03, 2022 at 10:14:41PM +0100, Matthew Wilcox (Oracle) wrote: > > > > This is the number of bits used by a PMD entry, not the order of a PMD. > > > > > > No, it's not the number of bits. A PMD entry doesn't fit in 2 or 3 bits. > > > This is even more confusing. > > > > Well, what is it then? The order of something is PAGE_SIZE << n, and > > that doesn't seem to be what this is. > > Where is it defined that "order" means "PAGE_SIZE << n" ? > > "order" here is "order of magnitude" and in this case, it is 2^n, just > like order of magnitude in base 10 is 10^n. So strictly, the usage > here is completely correct, but if you describe "order" as "PAGE_SIZE << > n" that is no longer an order of magnitude, because it doesn't increase > in an order of magnitude (iow, n = 2 isn't PAGE_SIZE * PAGE_SIZE). I'd go with PMD_ENTRY_ORDER as Russell suggested last year. From 6389dfb2e5ae5b040ca1c8f07a071d8da2873b13 Mon Sep 17 00:00:00 2001 From: Mike Rapoport <rppt@linux.ibm.com> Date: Mon, 4 Jul 2022 09:17:40 +0300 Subject: [PATCH] ARM: head.S: rename PMD_ORDER to PMD_ENTRY_ORDER PMD_ORDER denotes order of magnitude for a PMD entry, i.e PMD entry size is 2 ^ PMD_ORDER. Rename PMD_ORDER to PMD_ENTRY_ORDER to allow a generic definition of PMD_ORDER as order of a PMD allocation: (PMD_SHIFT - PAGE_SHIFT). Signed-off-by: Mike Rapoport <rppt@linux.ibm.com> --- arch/arm/kernel/head.S | 34 +++++++++++++++++----------------- 1 file changed, 17 insertions(+), 17 deletions(-) diff --git a/arch/arm/kernel/head.S b/arch/arm/kernel/head.S index 500612d3da2e..29e2900178a1 100644 --- a/arch/arm/kernel/head.S +++ b/arch/arm/kernel/head.S @@ -38,10 +38,10 @@ #ifdef CONFIG_ARM_LPAE /* LPAE requires an additional page for the PGD */ #define PG_DIR_SIZE 0x5000 -#define PMD_ORDER 3 +#define PMD_ENTRY_ORDER 3 /* PMD entry size is 2^PMD_ENTRY_ORDER */ #else #define PG_DIR_SIZE 0x4000 -#define PMD_ORDER 2 +#define PMD_ENTRY_ORDER 2 #endif .globl swapper_pg_dir @@ -240,7 +240,7 @@ __create_page_tables: mov r6, r6, lsr #SECTION_SHIFT 1: orr r3, r7, r5, lsl #SECTION_SHIFT @ flags + kernel base - str r3, [r4, r5, lsl #PMD_ORDER] @ identity mapping + str r3, [r4, r5, lsl #PMD_ENTRY_ORDER] @ identity mapping cmp r5, r6 addlo r5, r5, #1 @ next section blo 1b @@ -250,7 +250,7 @@ __create_page_tables: * set two variables to indicate the physical start and end of the * kernel. */ - add r0, r4, #KERNEL_OFFSET >> (SECTION_SHIFT - PMD_ORDER) + add r0, r4, #KERNEL_OFFSET >> (SECTION_SHIFT - PMD_ENTRY_ORDER) ldr r6, =(_end - 1) adr_l r5, kernel_sec_start @ _pa(kernel_sec_start) #if defined CONFIG_CPU_ENDIAN_BE8 || defined CONFIG_CPU_ENDIAN_BE32 @@ -259,8 +259,8 @@ __create_page_tables: str r8, [r5] @ Save physical start of kernel (LE) #endif orr r3, r8, r7 @ Add the MMU flags - add r6, r4, r6, lsr #(SECTION_SHIFT - PMD_ORDER) -1: str r3, [r0], #1 << PMD_ORDER + add r6, r4, r6, lsr #(SECTION_SHIFT - PMD_ENTRY_ORDER) +1: str r3, [r0], #1 << PMD_ENTRY_ORDER add r3, r3, #1 << SECTION_SHIFT cmp r0, r6 bls 1b @@ -280,14 +280,14 @@ __create_page_tables: mov r3, pc mov r3, r3, lsr #SECTION_SHIFT orr r3, r7, r3, lsl #SECTION_SHIFT - add r0, r4, #(XIP_START & 0xff000000) >> (SECTION_SHIFT - PMD_ORDER) - str r3, [r0, #((XIP_START & 0x00f00000) >> SECTION_SHIFT) << PMD_ORDER]! + add r0, r4, #(XIP_START & 0xff000000) >> (SECTION_SHIFT - PMD_ENTRY_ORDER) + str r3, [r0, #((XIP_START & 0x00f00000) >> SECTION_SHIFT) << PMD_ENTRY_ORDER]! ldr r6, =(_edata_loc - 1) - add r0, r0, #1 << PMD_ORDER - add r6, r4, r6, lsr #(SECTION_SHIFT - PMD_ORDER) + add r0, r0, #1 << PMD_ENTRY_ORDER + add r6, r4, r6, lsr #(SECTION_SHIFT - PMD_ENTRY_ORDER) 1: cmp r0, r6 add r3, r3, #1 << SECTION_SHIFT - strls r3, [r0], #1 << PMD_ORDER + strls r3, [r0], #1 << PMD_ENTRY_ORDER bls 1b #endif @@ -297,10 +297,10 @@ __create_page_tables: */ mov r0, r2, lsr #SECTION_SHIFT cmp r2, #0 - ldrne r3, =FDT_FIXED_BASE >> (SECTION_SHIFT - PMD_ORDER) + ldrne r3, =FDT_FIXED_BASE >> (SECTION_SHIFT - PMD_ENTRY_ORDER) addne r3, r3, r4 orrne r6, r7, r0, lsl #SECTION_SHIFT - strne r6, [r3], #1 << PMD_ORDER + strne r6, [r3], #1 << PMD_ENTRY_ORDER addne r6, r6, #1 << SECTION_SHIFT strne r6, [r3] @@ -319,7 +319,7 @@ __create_page_tables: addruart r7, r3, r0 mov r3, r3, lsr #SECTION_SHIFT - mov r3, r3, lsl #PMD_ORDER + mov r3, r3, lsl #PMD_ENTRY_ORDER add r0, r4, r3 mov r3, r7, lsr #SECTION_SHIFT @@ -349,7 +349,7 @@ __create_page_tables: * If we're using the NetWinder or CATS, we also need to map * in the 16550-type serial port for the debug messages */ - add r0, r4, #0xff000000 >> (SECTION_SHIFT - PMD_ORDER) + add r0, r4, #0xff000000 >> (SECTION_SHIFT - PMD_ENTRY_ORDER) orr r3, r7, #0x7c000000 str r3, [r0] #endif @@ -359,10 +359,10 @@ __create_page_tables: * Similar reasons here - for debug. This is * only for Acorn RiscPC architectures. */ - add r0, r4, #0x02000000 >> (SECTION_SHIFT - PMD_ORDER) + add r0, r4, #0x02000000 >> (SECTION_SHIFT - PMD_ENTRY_ORDER) orr r3, r7, #0x02000000 str r3, [r0] - add r0, r4, #0xd8000000 >> (SECTION_SHIFT - PMD_ORDER) + add r0, r4, #0xd8000000 >> (SECTION_SHIFT - PMD_ENTRY_ORDER) str r3, [r0] #endif #endif -- 2.34.1 -- Sincerely yours, Mike. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2022-07-04 6:26 UTC|newest] Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top 2022-07-03 14:11 [PATCH 00/14] arch: make PxD_ORDER generically available Mike Rapoport 2022-07-03 14:11 ` [PATCH 01/14] csky: drop definition of PTE_ORDER Mike Rapoport 2022-07-03 14:11 ` [PATCH 02/14] csky: drop definition of PGD_ORDER Mike Rapoport 2022-07-03 14:11 ` [PATCH 03/14] mips: Rename PMD_ORDER to PMD_TABLE_ORDER Mike Rapoport 2022-07-03 14:11 ` [PATCH 04/14] mips: Rename PUD_ORDER to PUD_TABLE_ORDER Mike Rapoport 2022-07-03 14:11 ` [PATCH 05/14] mips: drop definitions of PTE_ORDER Mike Rapoport 2022-07-03 14:11 ` [PATCH 06/14] mips: Rename PGD_ORDER to PGD_TABLE_ORDER Mike Rapoport 2022-07-03 14:11 ` [PATCH 07/14] nios2: drop definition of PTE_ORDER Mike Rapoport 2022-07-03 14:11 ` [PATCH 08/14] nios2: drop definition of PGD_ORDER Mike Rapoport 2022-07-03 14:11 ` [PATCH 09/14] loongarch: drop definition of PTE_ORDER Mike Rapoport 2022-07-03 14:11 ` [PATCH 10/14] loongarch: drop definition of PMD_ORDER Mike Rapoport 2022-07-03 14:12 ` [PATCH 11/14] loongarch: drop definition of PUD_ORDER Mike Rapoport 2022-07-03 14:12 ` [PATCH 12/14] loongarch: drop definition of PGD_ORDER Mike Rapoport 2022-07-03 20:50 ` Matthew Wilcox 2022-07-04 3:57 ` WANG Xuerui 2022-07-04 6:37 ` Mike Rapoport 2022-07-03 14:12 ` [PATCH 13/14] parisc: Rename PGD_ORDER to PGD_TABLE_ORDER Mike Rapoport 2022-07-03 14:12 ` [PATCH 14/14] xtensa: drop definition of PGD_ORDER Mike Rapoport 2022-07-03 14:27 ` [PATCH 00/14] arch: make PxD_ORDER generically available Helge Deller 2022-07-04 0:40 ` Huacai Chen 2022-07-04 1:45 ` Guo Ren 2022-07-03 21:14 ` [PATCH 15/14] arm: Rename PMD_ORDER to PMD_BITS Matthew Wilcox (Oracle) 2022-07-03 21:14 ` Matthew Wilcox (Oracle) 2022-07-03 21:16 ` Russell King (Oracle) 2022-07-03 21:16 ` Russell King (Oracle) 2022-07-03 21:54 ` Matthew Wilcox 2022-07-03 21:54 ` Matthew Wilcox 2022-07-04 4:32 ` Russell King (Oracle) 2022-07-04 4:32 ` Russell King (Oracle) 2022-07-04 6:26 ` Mike Rapoport [this message] 2022-07-04 6:26 ` Mike Rapoport 2022-07-04 11:37 ` Russell King (Oracle) 2022-07-04 11:37 ` Russell King (Oracle) 2022-07-04 10:48 ` Matthew Wilcox 2022-07-04 10:48 ` Matthew Wilcox 2022-07-04 11:32 ` Russell King (Oracle) 2022-07-04 11:32 ` Russell King (Oracle) 2022-07-04 14:28 ` Matthew Wilcox 2022-07-04 14:28 ` Matthew Wilcox 2022-07-04 17:22 ` Russell King (Oracle) 2022-07-04 17:22 ` Russell King (Oracle)
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