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arm64: Get rid of struct cpu_table

PATCH New Marc Zyngier 5 participants 7 messages Mar 13, 2015 – Mar 17, 2015 arm64

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Marc Zyngier

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#0 lore raw

PATCH 1/1 arm64: Get rid of struct cpu_table

struct cpu_table is an artifact left from the (very) early days of the arm64 port, and its only real use is to allow the most beautiful "AArch64 Processor" string to be displayed at boot time.

Really? Yes, really.

Let's get rid of it. In order to avoid another BogoMips-gate, the aforementioned string is preserved.

Acked-by Catalin Marinas <[email protected]>
Signed-off-by Marc Zyngier <[email protected]>
---
 arch/arm64/include/asm/cputable.h | 30 -------------------
 arch/arm64/kernel/Makefile        |  2 +-
 arch/arm64/kernel/asm-offsets.c   |  4 ---
 arch/arm64/kernel/cputable.c      | 33 ---------------------
 arch/arm64/kernel/head.S          | 61 ++++-----------------------------------
 arch/arm64/kernel/setup.c         | 16 ++--------
 6 files changed, 9 insertions(+), 137 deletions(-)
 delete mode 100644 arch/arm64/include/asm/cputable.h
 delete mode 100644 arch/arm64/kernel/cputable.c
arch/arm64/include/asm/cputable.h deleted +0 -30
deleted file mode 100644
index e3bd983..0000000
@@ -1,30 +0,0 @@
-/*
- * arch/arm64/include/asm/cputable.h
- *
- * Copyright (C) 2012 ARM Ltd.
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see <http://www.gnu.org/licenses/>.
- */
-#ifndef __ASM_CPUTABLE_H
-#define __ASM_CPUTABLE_H
-
-struct cpu_info {
-	unsigned int	cpu_id_val;
-	unsigned int	cpu_id_mask;
-	const char	*cpu_name;
-	unsigned long	(*cpu_setup)(void);
-};
-
-extern struct cpu_info *lookup_processor_type(unsigned int);
-
-#endif
arch/arm64/kernel/Makefile +1 -1
index 5ee07ee..d5e7074 100644
@@ -12,7 +12,7 @@ CFLAGS_REMOVE_insn.o = -pg
 CFLAGS_REMOVE_return_address.o = -pg
 
 # Object file lists.
-arm64-obj-y		:= cputable.o debug-monitors.o entry.o irq.o fpsimd.o	\
+arm64-obj-y		:= debug-monitors.o entry.o irq.o fpsimd.o		\
 			   entry-fpsimd.o process.o ptrace.o setup.o signal.o	\
 			   sys.o stacktrace.o time.o traps.o io.o vdso.o	\
 			   hyp-stub.o psci.o psci-call.o cpu_ops.o insn.o	\
arch/arm64/kernel/asm-offsets.c +0 -4
index f7fa65d..14dd3d1 100644
@@ -24,7 +24,6 @@
 #include <linux/kvm_host.h>
 #include <asm/thread_info.h>
 #include <asm/memory.h>
-#include <asm/cputable.h>
 #include <asm/smp_plat.h>
 #include <asm/suspend.h>
 #include <asm/vdso_datapage.h>

@@ -71,9 +70,6 @@ int main(void)
   BLANK();
   DEFINE(PAGE_SZ,	       	PAGE_SIZE);
   BLANK();
-  DEFINE(CPU_INFO_SZ,		sizeof(struct cpu_info));
-  DEFINE(CPU_INFO_SETUP,	offsetof(struct cpu_info, cpu_setup));
-  BLANK();
   DEFINE(DMA_BIDIRECTIONAL,	DMA_BIDIRECTIONAL);
   DEFINE(DMA_TO_DEVICE,		DMA_TO_DEVICE);
   DEFINE(DMA_FROM_DEVICE,	DMA_FROM_DEVICE);
arch/arm64/kernel/cputable.c deleted +0 -33
deleted file mode 100644
index fd3993c..0000000
@@ -1,33 +0,0 @@
-/*
- * arch/arm64/kernel/cputable.c
- *
- * Copyright (C) 2012 ARM Ltd.
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see <http://www.gnu.org/licenses/>.
- */
-
-#include <linux/init.h>
-
-#include <asm/cputable.h>
-
-extern unsigned long __cpu_setup(void);
-
-struct cpu_info cpu_table[] = {
-	{
-		.cpu_id_val	= 0x000f0000,
-		.cpu_id_mask	= 0x000f0000,
-		.cpu_name	= "AArch64 Processor",
-		.cpu_setup	= __cpu_setup,
-	},
-	{ /* Empty */ },
-};
arch/arm64/kernel/head.S +6 -55

88 lines not on this page · raw message

arch/arm64/kernel/setup.c +2 -14
index e8420f6..a19eae2 100644
@@ -50,7 +50,6 @@
 #include <asm/cpu.h>
 #include <asm/cputype.h>
 #include <asm/elf.h>
-#include <asm/cputable.h>
 #include <asm/cpufeature.h>
 #include <asm/cpu_ops.h>
 #include <asm/sections.h>

@@ -83,7 +82,6 @@ unsigned int compat_elf_hwcap2 __read_mostly;
 
 DECLARE_BITMAP(cpu_hwcaps, ARM64_NCAPS);
 
-static const char *cpu_name;
 phys_addr_t __fdt_pointer __initdata;
 
 /*

@@ -209,22 +207,12 @@ static void __init smp_build_mpidr_hash(void)
 
 static void __init setup_processor(void)
 {
-	struct cpu_info *cpu_info;
 	u64 features, block;
 	u32 cwg;
 	int cls;
 
-	cpu_info = lookup_processor_type(read_cpuid_id());
-	if (!cpu_info) {
-		printk("CPU configuration botched (ID %08x), unable to continue.\n",
-		       read_cpuid_id());
-		while (1);
-	}
-
-	cpu_name = cpu_info->cpu_name;
-
-	printk("CPU: %s [%08x] revision %d\n",
-	       cpu_name, read_cpuid_id(), read_cpuid_id() & 15);
+	printk("CPU: AArch64 Processor [%08x] revision %d\n",
+	       read_cpuid_id(), read_cpuid_id() & 15);
 
 	sprintf(init_utsname()->machine, ELF_PLATFORM);
 	elf_hwcap = 0;
Signature · 1 line
2.1.4
#1 lore raw

PATCH 1/1 arm64: Get rid of struct cpu_table

Quoted 4 lines · On Friday 13 March 2015 12:02:13 Marc Zyngier wrote:

struct cpu_table is an artifact left from the (very) early days of the arm64 port, and its only real use is to allow the most beautiful "AArch64 Processor" string to be displayed at boot time.

Quoted 8 lines

Really? Yes, really.

Let's get rid of it. In order to avoid another BogoMips-gate, the aforementioned string is preserved.

Acked-by Catalin Marinas <[email protected]>
Signed-off-by Marc Zyngier <[email protected]>

Nice catch!

Arnd

#2 lore raw

PATCH 1/1 arm64: Get rid of struct cpu_table

In reply to Marc Zyngier
Quoted 4 lines · Marc Zyngier

struct cpu_table is an artifact left from the (very) early days of the arm64 port, and its only real use is to allow the most beautiful "AArch64 Processor" string to be displayed at boot time.

Heh, I looked at that code and assumed it was there for a reason. Apparently not :-)

Acked-by Ard Biesheuvel <[email protected]>

Some comments below.

Quoted 158 lines

Really? Yes, really.

Let's get rid of it. In order to avoid another BogoMips-gate, the aforementioned string is preserved.

Acked-by Catalin Marinas <[email protected]>
Signed-off-by Marc Zyngier <[email protected]>
---
 arch/arm64/include/asm/cputable.h | 30 -------------------
 arch/arm64/kernel/Makefile        |  2 +-
 arch/arm64/kernel/asm-offsets.c   |  4 ---
 arch/arm64/kernel/cputable.c      | 33 ---------------------
 arch/arm64/kernel/head.S          | 61 ++++-----------------------------------
 arch/arm64/kernel/setup.c         | 16 ++--------
 6 files changed, 9 insertions(+), 137 deletions(-)
 delete mode 100644 arch/arm64/include/asm/cputable.h
 delete mode 100644 arch/arm64/kernel/cputable.c
arch/arm64/include/asm/cputable.h deleted +0 -30
deleted file mode 100644
index e3bd983..0000000
@@ -1,30 +0,0 @@
-/*
- * arch/arm64/include/asm/cputable.h
- *
- * Copyright (C) 2012 ARM Ltd.
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see <http://www.gnu.org/licenses/>.
- */
-#ifndef __ASM_CPUTABLE_H
-#define __ASM_CPUTABLE_H
-
-struct cpu_info {
-       unsigned int    cpu_id_val;
-       unsigned int    cpu_id_mask;
-       const char      *cpu_name;
-       unsigned long   (*cpu_setup)(void);
-};
-
-extern struct cpu_info *lookup_processor_type(unsigned int);
-
-#endif
arch/arm64/kernel/Makefile +1 -1
index 5ee07ee..d5e7074 100644
@@ -12,7 +12,7 @@ CFLAGS_REMOVE_insn.o = -pg
 CFLAGS_REMOVE_return_address.o = -pg
 
 # Object file lists.
-arm64-obj-y            := cputable.o debug-monitors.o entry.o irq.o fpsimd.o   \
+arm64-obj-y            := debug-monitors.o entry.o irq.o fpsimd.o              \
                           entry-fpsimd.o process.o ptrace.o setup.o signal.o   \
                           sys.o stacktrace.o time.o traps.o io.o vdso.o        \
                           hyp-stub.o psci.o psci-call.o cpu_ops.o insn.o       \
arch/arm64/kernel/asm-offsets.c +0 -4
index f7fa65d..14dd3d1 100644
@@ -24,7 +24,6 @@
 #include <linux/kvm_host.h>
 #include <asm/thread_info.h>
 #include <asm/memory.h>
-#include <asm/cputable.h>
 #include <asm/smp_plat.h>
 #include <asm/suspend.h>
 #include <asm/vdso_datapage.h>

@@ -71,9 +70,6 @@ int main(void)
   BLANK();
   DEFINE(PAGE_SZ,              PAGE_SIZE);
   BLANK();
-  DEFINE(CPU_INFO_SZ,          sizeof(struct cpu_info));
-  DEFINE(CPU_INFO_SETUP,       offsetof(struct cpu_info, cpu_setup));
-  BLANK();
   DEFINE(DMA_BIDIRECTIONAL,    DMA_BIDIRECTIONAL);
   DEFINE(DMA_TO_DEVICE,                DMA_TO_DEVICE);
   DEFINE(DMA_FROM_DEVICE,      DMA_FROM_DEVICE);
arch/arm64/kernel/cputable.c deleted +0 -33
deleted file mode 100644
index fd3993c..0000000
@@ -1,33 +0,0 @@
-/*
- * arch/arm64/kernel/cputable.c
- *
- * Copyright (C) 2012 ARM Ltd.
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see <http://www.gnu.org/licenses/>.
- */
-
-#include <linux/init.h>
-
-#include <asm/cputable.h>
-
-extern unsigned long __cpu_setup(void);
-
-struct cpu_info cpu_table[] = {
-       {
-               .cpu_id_val     = 0x000f0000,
-               .cpu_id_mask    = 0x000f0000,
-               .cpu_name       = "AArch64 Processor",
-               .cpu_setup      = __cpu_setup,
-       },
-       { /* Empty */ },
-};
arch/arm64/kernel/head.S +2 -12
index 8ce88e0..3ef9cbc 100644
@@ -245,22 +245,12 @@ ENTRY(stext)
        bl      __calc_phys_offset              // x24=PHYS_OFFSET, x28=PHYS_OFFSET-PAGE_OFFSET
        bl      set_cpu_boot_mode_flag
        mrs     x22, midr_el1                   // x22=cpuid
-       mov     x0, x22
-       bl      lookup_processor_type
-       mov     x23, x0                         // x23=current cpu_table
-       /*
-        * __error_p may end up out of range for cbz if text areas are
-        * aligned up to section sizes.
-        */
-       cbnz    x23, 1f                         // invalid processor (x23=0)?
-       b       __error_p
-1:
+
        bl      __vet_fdt
        bl      __create_page_tables            // x25=TTBR0, x26=TTBR1
        /*
         * The following calls CPU specific code in a position independent
-        * manner. See arch/arm64/mm/proc.S for details. x23 = base of
-        * cpu_info structure selected by lookup_processor_type above.
+        * manner. See arch/arm64/mm/proc.S for details.
         * On return, the CPU will be ready for the MMU to be turned on and
         * the TCR will have been set.
         */

arch/arm64/kernel/head.S ENTRY(stext) · line 263

Quoted 8 lines
arch/arm64/kernel/head.S +2 -2
@@ -268,8 +258,8 @@ ENTRY(stext)
                                                // MMU has been enabled
        adrp    lr, __enable_mmu                // return (PIC) address
        add     lr, lr, #:lo12:__enable_mmu
-       ldr     x12, [x23, #CPU_INFO_SETUP]
-       add     x12, x12, x28                   // __virt_to_phys
+       adrp    x12, __cpu_setup
+       add     x12, x12, #:lo12:__cpu_setup
        br      x12                             // initialise processor

b __cpu_setup ?

Quoted 8 lines
arch/arm64/kernel/head.S +0 -2
 ENDPROC(stext)
 

@@ -634,14 +624,10 @@ ENTRY(secondary_startup)
         * Common entry point for secondary CPUs.
         */
        mrs     x22, midr_el1                   // x22=cpuid
-       mov     x0, x22
-       bl      lookup_processor_type

arch/arm64/kernel/head.S ENTRY(secondary_startup) · line 632

Quoted 10 lines
arch/arm64/kernel/head.S +2 -4
-       mov     x23, x0                         // x23=current cpu_table
-       cbz     x23, __error_p                  // invalid processor (x23=0)?
 
        pgtbl   x25, x26, x28                   // x25=TTBR0, x26=TTBR1
-       ldr     x12, [x23, #CPU_INFO_SETUP]
-       add     x12, x12, x28                   // __virt_to_phys
+       adrp    x12, __cpu_setup
+       add     x12, x12, #:lo12:__cpu_setup
        blr     x12                             // initialise processor

bl __cpu_setup ?

Quoted 93 lines
arch/arm64/kernel/head.S +0 -35
        ldr     x21, =secondary_data

@@ -721,38 +707,3 @@ __error:
 1:     nop
        b       1b
 ENDPROC(__error)
-
-/*
- * This function gets the processor ID in w0 and searches the cpu_table[] for
- * a match. It returns a pointer to the struct cpu_info it found. The
- * cpu_table[] must end with an empty (all zeros) structure.
- *
- * This routine can be called via C code and it needs to work with the MMU
- * both disabled and enabled (the offset is calculated automatically).
- */
-ENTRY(lookup_processor_type)
-       adr     x1, __lookup_processor_type_data
-       ldp     x2, x3, [x1]
-       sub     x1, x1, x2                      // get offset between VA and PA
-       add     x3, x3, x1                      // convert VA to PA
-1:
-       ldp     w5, w6, [x3]                    // load cpu_id_val and cpu_id_mask
-       cbz     w5, 2f                          // end of list?
-       and     w6, w6, w0
-       cmp     w5, w6
-       b.eq    3f
-       add     x3, x3, #CPU_INFO_SZ
-       b       1b
-2:
-       mov     x3, #0                          // unknown processor
-3:
-       mov     x0, x3
-       ret
-ENDPROC(lookup_processor_type)
-
-       .align  3
-       .type   __lookup_processor_type_data, %object
-__lookup_processor_type_data:
-       .quad   .
-       .quad   cpu_table
-       .size   __lookup_processor_type_data, . - __lookup_processor_type_data
arch/arm64/kernel/setup.c +2 -15
index e8420f6..a19eae2 100644
@@ -50,7 +50,6 @@
 #include <asm/cpu.h>
 #include <asm/cputype.h>
 #include <asm/elf.h>
-#include <asm/cputable.h>
 #include <asm/cpufeature.h>
 #include <asm/cpu_ops.h>
 #include <asm/sections.h>

@@ -83,7 +82,6 @@ unsigned int compat_elf_hwcap2 __read_mostly;
 
 DECLARE_BITMAP(cpu_hwcaps, ARM64_NCAPS);
 
-static const char *cpu_name;
 phys_addr_t __fdt_pointer __initdata;
 
 /*

@@ -209,22 +207,12 @@ static void __init smp_build_mpidr_hash(void)
 
 static void __init setup_processor(void)
 {
-       struct cpu_info *cpu_info;
        u64 features, block;
        u32 cwg;
        int cls;
 
-       cpu_info = lookup_processor_type(read_cpuid_id());
-       if (!cpu_info) {
-               printk("CPU configuration botched (ID %08x), unable to continue.\n",
-                      read_cpuid_id());
-               while (1);
-       }
-
-       cpu_name = cpu_info->cpu_name;
-
-       printk("CPU: %s [%08x] revision %d\n",
-              cpu_name, read_cpuid_id(), read_cpuid_id() & 15);
+       printk("CPU: AArch64 Processor [%08x] revision %d\n",
+              read_cpuid_id(), read_cpuid_id() & 15);
 
        sprintf(init_utsname()->machine, ELF_PLATFORM);
        elf_hwcap = 0;
--

2.1.4

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author
#3 lore raw

PATCH 1/1 arm64: Get rid of struct cpu_table

Hey Ard,

Quoted 8 lines · Ard Biesheuvel
Quoted 4 lines · Marc Zyngier

struct cpu_table is an artifact left from the (very) early days of the arm64 port, and its only real use is to allow the most beautiful "AArch64 Processor" string to be displayed at boot time.

Heh, I looked at that code and assumed it was there for a reason. Apparently not :-)

So did I, until I actually realised what it did... ;-)

Quoted 1 line
Acked-by Ard Biesheuvel <[email protected]>

Thanks.

Quoted 162 lines

Some comments below.

Quoted 160 lines

Really? Yes, really.

Let's get rid of it. In order to avoid another BogoMips-gate, the aforementioned string is preserved.

Acked-by Catalin Marinas <[email protected]>
Signed-off-by Marc Zyngier <[email protected]>
---
 arch/arm64/include/asm/cputable.h | 30 -------------------
 arch/arm64/kernel/Makefile        |  2 +-
 arch/arm64/kernel/asm-offsets.c   |  4 ---
 arch/arm64/kernel/cputable.c      | 33 ---------------------
 arch/arm64/kernel/head.S          | 61 ++++-----------------------------------
 arch/arm64/kernel/setup.c         | 16 ++--------
 6 files changed, 9 insertions(+), 137 deletions(-)
 delete mode 100644 arch/arm64/include/asm/cputable.h
 delete mode 100644 arch/arm64/kernel/cputable.c
arch/arm64/include/asm/cputable.h deleted +0 -30
deleted file mode 100644
index e3bd983..0000000
@@ -1,30 +0,0 @@
-/*
- * arch/arm64/include/asm/cputable.h
- *
- * Copyright (C) 2012 ARM Ltd.
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see <http://www.gnu.org/licenses/>.
- */
-#ifndef __ASM_CPUTABLE_H
-#define __ASM_CPUTABLE_H
-
-struct cpu_info {
-       unsigned int    cpu_id_val;
-       unsigned int    cpu_id_mask;
-       const char      *cpu_name;
-       unsigned long   (*cpu_setup)(void);
-};
-
-extern struct cpu_info *lookup_processor_type(unsigned int);
-
-#endif
arch/arm64/kernel/Makefile +1 -1
index 5ee07ee..d5e7074 100644
@@ -12,7 +12,7 @@ CFLAGS_REMOVE_insn.o = -pg
 CFLAGS_REMOVE_return_address.o = -pg
 
 # Object file lists.
-arm64-obj-y            := cputable.o debug-monitors.o entry.o irq.o fpsimd.o   \
+arm64-obj-y            := debug-monitors.o entry.o irq.o fpsimd.o              \
                           entry-fpsimd.o process.o ptrace.o setup.o signal.o   \
                           sys.o stacktrace.o time.o traps.o io.o vdso.o        \
                           hyp-stub.o psci.o psci-call.o cpu_ops.o insn.o       \
arch/arm64/kernel/asm-offsets.c +0 -4
index f7fa65d..14dd3d1 100644
@@ -24,7 +24,6 @@
 #include <linux/kvm_host.h>
 #include <asm/thread_info.h>
 #include <asm/memory.h>
-#include <asm/cputable.h>
 #include <asm/smp_plat.h>
 #include <asm/suspend.h>
 #include <asm/vdso_datapage.h>

@@ -71,9 +70,6 @@ int main(void)
   BLANK();
   DEFINE(PAGE_SZ,              PAGE_SIZE);
   BLANK();
-  DEFINE(CPU_INFO_SZ,          sizeof(struct cpu_info));
-  DEFINE(CPU_INFO_SETUP,       offsetof(struct cpu_info, cpu_setup));
-  BLANK();
   DEFINE(DMA_BIDIRECTIONAL,    DMA_BIDIRECTIONAL);
   DEFINE(DMA_TO_DEVICE,                DMA_TO_DEVICE);
   DEFINE(DMA_FROM_DEVICE,      DMA_FROM_DEVICE);
arch/arm64/kernel/cputable.c deleted +0 -33
deleted file mode 100644
index fd3993c..0000000
@@ -1,33 +0,0 @@
-/*
- * arch/arm64/kernel/cputable.c
- *
- * Copyright (C) 2012 ARM Ltd.
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see <http://www.gnu.org/licenses/>.
- */
-
-#include <linux/init.h>
-
-#include <asm/cputable.h>
-
-extern unsigned long __cpu_setup(void);
-
-struct cpu_info cpu_table[] = {
-       {
-               .cpu_id_val     = 0x000f0000,
-               .cpu_id_mask    = 0x000f0000,
-               .cpu_name       = "AArch64 Processor",
-               .cpu_setup      = __cpu_setup,
-       },
-       { /* Empty */ },
-};
arch/arm64/kernel/head.S +2 -12
index 8ce88e0..3ef9cbc 100644
@@ -245,22 +245,12 @@ ENTRY(stext)
        bl      __calc_phys_offset              // x24=PHYS_OFFSET, x28=PHYS_OFFSET-PAGE_OFFSET
        bl      set_cpu_boot_mode_flag
        mrs     x22, midr_el1                   // x22=cpuid
-       mov     x0, x22
-       bl      lookup_processor_type
-       mov     x23, x0                         // x23=current cpu_table
-       /*
-        * __error_p may end up out of range for cbz if text areas are
-        * aligned up to section sizes.
-        */
-       cbnz    x23, 1f                         // invalid processor (x23=0)?
-       b       __error_p
-1:
+
        bl      __vet_fdt
        bl      __create_page_tables            // x25=TTBR0, x26=TTBR1
        /*
         * The following calls CPU specific code in a position independent
-        * manner. See arch/arm64/mm/proc.S for details. x23 = base of
-        * cpu_info structure selected by lookup_processor_type above.
+        * manner. See arch/arm64/mm/proc.S for details.
         * On return, the CPU will be ready for the MMU to be turned on and
         * the TCR will have been set.
         */

@@ -268,8 +258,8 @@ ENTRY(stext)
                                                // MMU has been enabled
        adrp    lr, __enable_mmu                // return (PIC) address
Quoted 8 lines

arch/arm64/kernel/head.S ENTRY(stext) · line 263

Quoted 6 lines
arch/arm64/kernel/head.S +2 -2
        add     lr, lr, #:lo12:__enable_mmu
-       ldr     x12, [x23, #CPU_INFO_SETUP]
-       add     x12, x12, x28                   // __virt_to_phys
+       adrp    x12, __cpu_setup
+       add     x12, x12, #:lo12:__cpu_setup
        br      x12                             // initialise processor

b __cpu_setup ?

Yeah, it is unlikely that the kernel will soon grow to be bigger than 128MB...

Quoted 11 lines
Quoted 11 lines
arch/arm64/kernel/head.S +0 -4
 ENDPROC(stext)
 

@@ -634,14 +624,10 @@ ENTRY(secondary_startup)
         * Common entry point for secondary CPUs.
         */
        mrs     x22, midr_el1                   // x22=cpuid
-       mov     x0, x22
-       bl      lookup_processor_type
-       mov     x23, x0                         // x23=current cpu_table
-       cbz     x23, __error_p                  // invalid processor (x23=0)?
Quoted 9 lines

arch/arm64/kernel/head.S ENTRY(secondary_startup) · line 632

Quoted 7 lines
arch/arm64/kernel/head.S +2 -2
        pgtbl   x25, x26, x28                   // x25=TTBR0, x26=TTBR1
-       ldr     x12, [x23, #CPU_INFO_SETUP]
-       add     x12, x12, x28                   // __virt_to_phys
+       adrp    x12, __cpu_setup
+       add     x12, x12, #:lo12:__cpu_setup
        blr     x12                             // initialise processor

bl __cpu_setup ?

Yup, same. I'll fix that.

Thanks,

	M.
Signature · 1 line
Jazz is not dead. It just smells funny...
#4 lore raw

PATCH 1/1 arm64: Get rid of struct cpu_table

Quoted 157 lines · Marc Zyngier

Hey Ard,

Quoted 8 lines · Ard Biesheuvel
Quoted 4 lines · Marc Zyngier

struct cpu_table is an artifact left from the (very) early days of the arm64 port, and its only real use is to allow the most beautiful "AArch64 Processor" string to be displayed at boot time.

Heh, I looked at that code and assumed it was there for a reason. Apparently not :-)

So did I, until I actually realised what it did... ;-)

Quoted 1 line
Acked-by Ard Biesheuvel <[email protected]>

Thanks.

Quoted 139 lines

Some comments below.

Quoted 137 lines

Really? Yes, really.

Let's get rid of it. In order to avoid another BogoMips-gate, the aforementioned string is preserved.

Acked-by Catalin Marinas <[email protected]>
Signed-off-by Marc Zyngier <[email protected]>
---
 arch/arm64/include/asm/cputable.h | 30 -------------------
 arch/arm64/kernel/Makefile        |  2 +-
 arch/arm64/kernel/asm-offsets.c   |  4 ---
 arch/arm64/kernel/cputable.c      | 33 ---------------------
 arch/arm64/kernel/head.S          | 61 ++++-----------------------------------
 arch/arm64/kernel/setup.c         | 16 ++--------
 6 files changed, 9 insertions(+), 137 deletions(-)
 delete mode 100644 arch/arm64/include/asm/cputable.h
 delete mode 100644 arch/arm64/kernel/cputable.c
arch/arm64/include/asm/cputable.h deleted +0 -30
deleted file mode 100644
index e3bd983..0000000
@@ -1,30 +0,0 @@
-/*
- * arch/arm64/include/asm/cputable.h
- *
- * Copyright (C) 2012 ARM Ltd.
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see <http://www.gnu.org/licenses/>.
- */
-#ifndef __ASM_CPUTABLE_H
-#define __ASM_CPUTABLE_H
-
-struct cpu_info {
-       unsigned int    cpu_id_val;
-       unsigned int    cpu_id_mask;
-       const char      *cpu_name;
-       unsigned long   (*cpu_setup)(void);
-};
-
-extern struct cpu_info *lookup_processor_type(unsigned int);
-
-#endif
arch/arm64/kernel/Makefile +1 -1
index 5ee07ee..d5e7074 100644
@@ -12,7 +12,7 @@ CFLAGS_REMOVE_insn.o = -pg
 CFLAGS_REMOVE_return_address.o = -pg
 
 # Object file lists.
-arm64-obj-y            := cputable.o debug-monitors.o entry.o irq.o fpsimd.o   \
+arm64-obj-y            := debug-monitors.o entry.o irq.o fpsimd.o              \
                           entry-fpsimd.o process.o ptrace.o setup.o signal.o   \
                           sys.o stacktrace.o time.o traps.o io.o vdso.o        \
                           hyp-stub.o psci.o psci-call.o cpu_ops.o insn.o       \
arch/arm64/kernel/asm-offsets.c +0 -4
index f7fa65d..14dd3d1 100644
@@ -24,7 +24,6 @@
 #include <linux/kvm_host.h>
 #include <asm/thread_info.h>
 #include <asm/memory.h>
-#include <asm/cputable.h>
 #include <asm/smp_plat.h>
 #include <asm/suspend.h>
 #include <asm/vdso_datapage.h>

@@ -71,9 +70,6 @@ int main(void)
   BLANK();
   DEFINE(PAGE_SZ,              PAGE_SIZE);
   BLANK();
-  DEFINE(CPU_INFO_SZ,          sizeof(struct cpu_info));
-  DEFINE(CPU_INFO_SETUP,       offsetof(struct cpu_info, cpu_setup));
-  BLANK();
   DEFINE(DMA_BIDIRECTIONAL,    DMA_BIDIRECTIONAL);
   DEFINE(DMA_TO_DEVICE,                DMA_TO_DEVICE);
   DEFINE(DMA_FROM_DEVICE,      DMA_FROM_DEVICE);
arch/arm64/kernel/cputable.c deleted +0 -33
deleted file mode 100644
index fd3993c..0000000
@@ -1,33 +0,0 @@
-/*
- * arch/arm64/kernel/cputable.c
- *
- * Copyright (C) 2012 ARM Ltd.
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see <http://www.gnu.org/licenses/>.
- */
-
-#include <linux/init.h>
-
-#include <asm/cputable.h>
-
-extern unsigned long __cpu_setup(void);
-
-struct cpu_info cpu_table[] = {
-       {
-               .cpu_id_val     = 0x000f0000,
-               .cpu_id_mask    = 0x000f0000,
-               .cpu_name       = "AArch64 Processor",
-               .cpu_setup      = __cpu_setup,
-       },
-       { /* Empty */ },
-};
arch/arm64/kernel/head.S +0 -1
index 8ce88e0..3ef9cbc 100644
@@ -245,22 +245,12 @@ ENTRY(stext)
        bl      __calc_phys_offset              // x24=PHYS_OFFSET, x28=PHYS_OFFSET-PAGE_OFFSET
        bl      set_cpu_boot_mode_flag
        mrs     x22, midr_el1                   // x22=cpuid
-       mov     x0, x22
Quoted 8 lines
Quoted 8 lines

arch/arm64/kernel/head.S ENTRY(stext) · line 256

Quoted 8 lines
arch/arm64/kernel/head.S +0 -8
-       bl      lookup_processor_type
-       mov     x23, x0                         // x23=current cpu_table
-       /*
-        * __error_p may end up out of range for cbz if text areas are
-        * aligned up to section sizes.
-        */
-       cbnz    x23, 1f                         // invalid processor (x23=0)?
-       b       __error_p

As I mentioned oob, __error_p etc can be removed in its entirety as well.

Quoted 55 lines
Quoted 15 lines
Quoted 15 lines
arch/arm64/kernel/head.S +2 -3
-1:
+
        bl      __vet_fdt
        bl      __create_page_tables            // x25=TTBR0, x26=TTBR1
        /*
         * The following calls CPU specific code in a position independent
-        * manner. See arch/arm64/mm/proc.S for details. x23 = base of
-        * cpu_info structure selected by lookup_processor_type above.
+        * manner. See arch/arm64/mm/proc.S for details.
         * On return, the CPU will be ready for the MMU to be turned on and
         * the TCR will have been set.
         */

@@ -268,8 +258,8 @@ ENTRY(stext)
                                                // MMU has been enabled
        adrp    lr, __enable_mmu                // return (PIC) address
Quoted 8 lines

arch/arm64/kernel/head.S ENTRY(stext) · line 263

Quoted 6 lines
arch/arm64/kernel/head.S +2 -2
        add     lr, lr, #:lo12:__enable_mmu
-       ldr     x12, [x23, #CPU_INFO_SETUP]
-       add     x12, x12, x28                   // __virt_to_phys
+       adrp    x12, __cpu_setup
+       add     x12, x12, #:lo12:__cpu_setup
        br      x12                             // initialise processor

b __cpu_setup ?

Yeah, it is unlikely that the kernel will soon grow to be bigger than 128MB...

Quoted 11 lines
Quoted 11 lines
arch/arm64/kernel/head.S +0 -4
 ENDPROC(stext)
 

@@ -634,14 +624,10 @@ ENTRY(secondary_startup)
         * Common entry point for secondary CPUs.
         */
        mrs     x22, midr_el1                   // x22=cpuid
-       mov     x0, x22
-       bl      lookup_processor_type
-       mov     x23, x0                         // x23=current cpu_table
-       cbz     x23, __error_p                  // invalid processor (x23=0)?
Quoted 9 lines

arch/arm64/kernel/head.S ENTRY(secondary_startup) · line 632

Quoted 7 lines
arch/arm64/kernel/head.S +2 -2
        pgtbl   x25, x26, x28                   // x25=TTBR0, x26=TTBR1
-       ldr     x12, [x23, #CPU_INFO_SETUP]
-       add     x12, x12, x28                   // __virt_to_phys
+       adrp    x12, __cpu_setup
+       add     x12, x12, #:lo12:__cpu_setup
        blr     x12                             // initialise processor

bl __cpu_setup ?

Yup, same. I'll fix that.

Thanks,

        M.

--
Jazz is not dead. It just smells funny...

maintainer
#5 lore raw

PATCH 1/1 arm64: Get rid of struct cpu_table

In reply to Ard Biesheuvel
Quoted 7 lines · Ard Biesheuvel
Quoted 3 lines · Marc Zyngier

struct cpu_table is an artifact left from the (very) early days of the arm64 port, and its only real use is to allow the most beautiful "AArch64 Processor" string to be displayed at boot time.

Heh, I looked at that code and assumed it was there for a reason. Apparently not :-)

There's a very good reason _not_ to be there: it encourages people to add implementation specific tweaks to the early kernel boot code. These must be done in firmware or boot-loader.

Signature · 1 line
Catalin
reviewer
#6 lore raw

PATCH 1/1 arm64: Get rid of struct cpu_table

In reply to Marc Zyngier
Quoted 8 lines · Marc Zyngier

struct cpu_table is an artifact left from the (very) early days of the arm64 port, and its only real use is to allow the most beautiful "AArch64 Processor" string to be displayed at boot time.

Really? Yes, really.

Let's get rid of it. In order to avoid another BogoMips-gate, the aforementioned string is preserved.

Nice!

Quoted 2 lines
Acked-by Catalin Marinas <[email protected]>
Signed-off-by Marc Zyngier <[email protected]>
Acked-by Mark Rutland <[email protected]>
Quoted 271 lines
---
 arch/arm64/include/asm/cputable.h | 30 -------------------
 arch/arm64/kernel/Makefile        |  2 +-
 arch/arm64/kernel/asm-offsets.c   |  4 ---
 arch/arm64/kernel/cputable.c      | 33 ---------------------
 arch/arm64/kernel/head.S          | 61 ++++-----------------------------------
 arch/arm64/kernel/setup.c         | 16 ++--------
 6 files changed, 9 insertions(+), 137 deletions(-)
 delete mode 100644 arch/arm64/include/asm/cputable.h
 delete mode 100644 arch/arm64/kernel/cputable.c
arch/arm64/include/asm/cputable.h deleted +0 -30
deleted file mode 100644
index e3bd983..0000000
@@ -1,30 +0,0 @@
-/*
- * arch/arm64/include/asm/cputable.h
- *
- * Copyright (C) 2012 ARM Ltd.
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see <http://www.gnu.org/licenses/>.
- */
-#ifndef __ASM_CPUTABLE_H
-#define __ASM_CPUTABLE_H
-
-struct cpu_info {
-	unsigned int	cpu_id_val;
-	unsigned int	cpu_id_mask;
-	const char	*cpu_name;
-	unsigned long	(*cpu_setup)(void);
-};
-
-extern struct cpu_info *lookup_processor_type(unsigned int);
-
-#endif
arch/arm64/kernel/Makefile +1 -1
index 5ee07ee..d5e7074 100644
@@ -12,7 +12,7 @@ CFLAGS_REMOVE_insn.o = -pg
 CFLAGS_REMOVE_return_address.o = -pg
 
 # Object file lists.
-arm64-obj-y		:= cputable.o debug-monitors.o entry.o irq.o fpsimd.o	\
+arm64-obj-y		:= debug-monitors.o entry.o irq.o fpsimd.o		\
 			   entry-fpsimd.o process.o ptrace.o setup.o signal.o	\
 			   sys.o stacktrace.o time.o traps.o io.o vdso.o	\
 			   hyp-stub.o psci.o psci-call.o cpu_ops.o insn.o	\
arch/arm64/kernel/asm-offsets.c +0 -4
index f7fa65d..14dd3d1 100644
@@ -24,7 +24,6 @@
 #include <linux/kvm_host.h>
 #include <asm/thread_info.h>
 #include <asm/memory.h>
-#include <asm/cputable.h>
 #include <asm/smp_plat.h>
 #include <asm/suspend.h>
 #include <asm/vdso_datapage.h>

@@ -71,9 +70,6 @@ int main(void)
   BLANK();
   DEFINE(PAGE_SZ,	       	PAGE_SIZE);
   BLANK();
-  DEFINE(CPU_INFO_SZ,		sizeof(struct cpu_info));
-  DEFINE(CPU_INFO_SETUP,	offsetof(struct cpu_info, cpu_setup));
-  BLANK();
   DEFINE(DMA_BIDIRECTIONAL,	DMA_BIDIRECTIONAL);
   DEFINE(DMA_TO_DEVICE,		DMA_TO_DEVICE);
   DEFINE(DMA_FROM_DEVICE,	DMA_FROM_DEVICE);
arch/arm64/kernel/cputable.c deleted +0 -33
deleted file mode 100644
index fd3993c..0000000
@@ -1,33 +0,0 @@
-/*
- * arch/arm64/kernel/cputable.c
- *
- * Copyright (C) 2012 ARM Ltd.
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see <http://www.gnu.org/licenses/>.
- */
-
-#include <linux/init.h>
-
-#include <asm/cputable.h>
-
-extern unsigned long __cpu_setup(void);
-
-struct cpu_info cpu_table[] = {
-	{
-		.cpu_id_val	= 0x000f0000,
-		.cpu_id_mask	= 0x000f0000,
-		.cpu_name	= "AArch64 Processor",
-		.cpu_setup	= __cpu_setup,
-	},
-	{ /* Empty */ },
-};
arch/arm64/kernel/head.S +6 -55
index 8ce88e0..3ef9cbc 100644
@@ -245,22 +245,12 @@ ENTRY(stext)
 	bl	__calc_phys_offset		// x24=PHYS_OFFSET, x28=PHYS_OFFSET-PAGE_OFFSET
 	bl	set_cpu_boot_mode_flag
 	mrs	x22, midr_el1			// x22=cpuid
-	mov	x0, x22
-	bl	lookup_processor_type
-	mov	x23, x0				// x23=current cpu_table
-	/*
-	 * __error_p may end up out of range for cbz if text areas are
-	 * aligned up to section sizes.
-	 */
-	cbnz	x23, 1f				// invalid processor (x23=0)?
-	b	__error_p
-1:
+
 	bl	__vet_fdt
 	bl	__create_page_tables		// x25=TTBR0, x26=TTBR1
 	/*
 	 * The following calls CPU specific code in a position independent
-	 * manner. See arch/arm64/mm/proc.S for details. x23 = base of
-	 * cpu_info structure selected by lookup_processor_type above.
+	 * manner. See arch/arm64/mm/proc.S for details.
 	 * On return, the CPU will be ready for the MMU to be turned on and
 	 * the TCR will have been set.
 	 */

@@ -268,8 +258,8 @@ ENTRY(stext)
 						// MMU has been enabled
 	adrp	lr, __enable_mmu		// return (PIC) address
 	add	lr, lr, #:lo12:__enable_mmu
-	ldr	x12, [x23, #CPU_INFO_SETUP]
-	add	x12, x12, x28			// __virt_to_phys
+	adrp	x12, __cpu_setup
+	add	x12, x12, #:lo12:__cpu_setup
 	br	x12				// initialise processor
 ENDPROC(stext)
 

@@ -634,14 +624,10 @@ ENTRY(secondary_startup)
 	 * Common entry point for secondary CPUs.
 	 */
 	mrs	x22, midr_el1			// x22=cpuid
-	mov	x0, x22
-	bl	lookup_processor_type
-	mov	x23, x0				// x23=current cpu_table
-	cbz	x23, __error_p			// invalid processor (x23=0)?
 
 	pgtbl	x25, x26, x28			// x25=TTBR0, x26=TTBR1
-	ldr	x12, [x23, #CPU_INFO_SETUP]
-	add	x12, x12, x28			// __virt_to_phys
+	adrp	x12, __cpu_setup
+	add	x12, x12, #:lo12:__cpu_setup
 	blr	x12				// initialise processor
 
 	ldr	x21, =secondary_data

@@ -721,38 +707,3 @@ __error:
 1:	nop
 	b	1b
 ENDPROC(__error)
-
-/*
- * This function gets the processor ID in w0 and searches the cpu_table[] for
- * a match. It returns a pointer to the struct cpu_info it found. The
- * cpu_table[] must end with an empty (all zeros) structure.
- *
- * This routine can be called via C code and it needs to work with the MMU
- * both disabled and enabled (the offset is calculated automatically).
- */
-ENTRY(lookup_processor_type)
-	adr	x1, __lookup_processor_type_data
-	ldp	x2, x3, [x1]
-	sub	x1, x1, x2			// get offset between VA and PA
-	add	x3, x3, x1			// convert VA to PA
-1:
-	ldp	w5, w6, [x3]			// load cpu_id_val and cpu_id_mask
-	cbz	w5, 2f				// end of list?
-	and	w6, w6, w0
-	cmp	w5, w6
-	b.eq	3f
-	add	x3, x3, #CPU_INFO_SZ
-	b	1b
-2:
-	mov	x3, #0				// unknown processor
-3:
-	mov	x0, x3
-	ret
-ENDPROC(lookup_processor_type)
-
-	.align	3
-	.type	__lookup_processor_type_data, %object
-__lookup_processor_type_data:
-	.quad	.
-	.quad	cpu_table
-	.size	__lookup_processor_type_data, . - __lookup_processor_type_data
arch/arm64/kernel/setup.c +2 -14
index e8420f6..a19eae2 100644
@@ -50,7 +50,6 @@
 #include <asm/cpu.h>
 #include <asm/cputype.h>
 #include <asm/elf.h>
-#include <asm/cputable.h>
 #include <asm/cpufeature.h>
 #include <asm/cpu_ops.h>
 #include <asm/sections.h>

@@ -83,7 +82,6 @@ unsigned int compat_elf_hwcap2 __read_mostly;
 
 DECLARE_BITMAP(cpu_hwcaps, ARM64_NCAPS);
 
-static const char *cpu_name;
 phys_addr_t __fdt_pointer __initdata;
 
 /*

@@ -209,22 +207,12 @@ static void __init smp_build_mpidr_hash(void)
 
 static void __init setup_processor(void)
 {
-	struct cpu_info *cpu_info;
 	u64 features, block;
 	u32 cwg;
 	int cls;
 
-	cpu_info = lookup_processor_type(read_cpuid_id());
-	if (!cpu_info) {
-		printk("CPU configuration botched (ID %08x), unable to continue.\n",
-		       read_cpuid_id());
-		while (1);
-	}
-
-	cpu_name = cpu_info->cpu_name;
-
-	printk("CPU: %s [%08x] revision %d\n",
-	       cpu_name, read_cpuid_id(), read_cpuid_id() & 15);
+	printk("CPU: AArch64 Processor [%08x] revision %d\n",
+	       read_cpuid_id(), read_cpuid_id() & 15);
 
 	sprintf(init_utsname()->machine, ELF_PLATFORM);
 	elf_hwcap = 0;
Signature · 7 lines
2.1.4


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