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linux/arch/arm/kernel/head-nommu.S
Linus Walleij a9ff696160 ARM: mm: Make virt_to_pfn() a static inline 
Making virt_to_pfn() a static inline taking a strongly typed
(const void *) makes the contract of a passing a pointer of that
type to the function explicit and exposes any misuse of the
macro virt_to_pfn() acting polymorphic and accepting many types
such as (void *), (unitptr_t) or (unsigned long) as arguments
without warnings.

Doing this is a bit intrusive: virt_to_pfn() requires
PHYS_PFN_OFFSET and PAGE_SHIFT to be defined, and this is defined in
<asm/page.h>, so this must be included *before* <asm/memory.h>.

The use of macros were obscuring the unclear inclusion order here,
as the macros would eventually be resolved, but a static inline
like this cannot be compiled with unresolved macros.

The naive solution to include <asm/page.h> at the top of
<asm/memory.h> does not work, because <asm/memory.h> sometimes
includes <asm/page.h> at the end of itself, which would create a
confusing inclusion loop. So instead, take the approach to always
unconditionally include <asm/page.h> at the end of <asm/memory.h>

arch/arm uses <asm/memory.h> explicitly in a lot of places,
however it turns out that if we just unconditionally include
<asm/memory.h> into <asm/page.h> and switch all inclusions of
<asm/memory.h> to <asm/page.h> instead, we enforce the right
order and <asm/memory.h> will always have access to the
definitions.

Put an inclusion guard in place making it impossible to include
<asm/memory.h> explicitly.

Link: https://lore.kernel.org/linux-mm/20220701160004.2ffff4e5ab59a55499f4c736@linux-foundation.org/
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2023-05-29 11:27:08 +02:00

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/* SPDX-License-Identifier: GPL-2.0-only */
/*
* linux/arch/arm/kernel/head-nommu.S
*
* Copyright (C) 1994-2002 Russell King
* Copyright (C) 2003-2006 Hyok S. Choi
*
* Common kernel startup code (non-paged MM)
*/
#include <linux/linkage.h>
#include <linux/init.h>
#include <linux/errno.h>
#include <asm/assembler.h>
#include <asm/ptrace.h>
#include <asm/asm-offsets.h>
#include <asm/page.h>
#include <asm/cp15.h>
#include <asm/thread_info.h>
#include <asm/v7m.h>
#include <asm/mpu.h>
/*
* Kernel startup entry point.
* ---------------------------
*
* This is normally called from the decompressor code. The requirements
* are: MMU = off, D-cache = off, I-cache = dont care, r0 = 0,
* r1 = machine nr.
*
* See linux/arch/arm/tools/mach-types for the complete list of machine
* numbers for r1.
*
*/
__HEAD
#ifdef CONFIG_CPU_THUMBONLY
.thumb
ENTRY(stext)
#else
.arm
ENTRY(stext)
THUMB( badr r9, 1f ) @ Kernel is always entered in ARM.
THUMB( bx r9 ) @ If this is a Thumb-2 kernel,
THUMB( .thumb ) @ switch to Thumb now.
THUMB(1: )
#endif
#ifdef CONFIG_ARM_VIRT_EXT
bl __hyp_stub_install
#endif
@ ensure svc mode and all interrupts masked
safe_svcmode_maskall r9
@ and irqs disabled
#if defined(CONFIG_CPU_CP15)
mrc p15, 0, r9, c0, c0 @ get processor id
#elif defined(CONFIG_CPU_V7M)
ldr r9, =BASEADDR_V7M_SCB
ldr r9, [r9, V7M_SCB_CPUID]
#else
ldr r9, =CONFIG_PROCESSOR_ID
#endif
bl __lookup_processor_type @ r5=procinfo r9=cpuid
movs r10, r5 @ invalid processor (r5=0)?
beq __error_p @ yes, error 'p'
#ifdef CONFIG_ARM_MPU
bl __setup_mpu
#endif
badr lr, 1f @ return (PIC) address
ldr r12, [r10, #PROCINFO_INITFUNC]
add r12, r12, r10
ret r12
1: ldr lr, =__mmap_switched
b __after_proc_init
ENDPROC(stext)
#ifdef CONFIG_SMP
.text
ENTRY(secondary_startup)
/*
* Common entry point for secondary CPUs.
*
* Ensure that we're in SVC mode, and IRQs are disabled. Lookup
* the processor type - there is no need to check the machine type
* as it has already been validated by the primary processor.
*/
#ifdef CONFIG_ARM_VIRT_EXT
bl __hyp_stub_install_secondary
#endif
safe_svcmode_maskall r9
#ifndef CONFIG_CPU_CP15
ldr r9, =CONFIG_PROCESSOR_ID
#else
mrc p15, 0, r9, c0, c0 @ get processor id
#endif
bl __lookup_processor_type @ r5=procinfo r9=cpuid
movs r10, r5 @ invalid processor?
beq __error_p @ yes, error 'p'
ldr r7, __secondary_data
#ifdef CONFIG_ARM_MPU
bl __secondary_setup_mpu @ Initialize the MPU
#endif
badr lr, 1f @ return (PIC) address
ldr r12, [r10, #PROCINFO_INITFUNC]
add r12, r12, r10
ret r12
1: bl __after_proc_init
ldr r7, __secondary_data @ reload r7
ldr sp, [r7, #12] @ set up the stack pointer
ldr r0, [r7, #16] @ set up task pointer
mov fp, #0
b secondary_start_kernel
ENDPROC(secondary_startup)
.type __secondary_data, %object
__secondary_data:
.long secondary_data
#endif /* CONFIG_SMP */
/*
* Set the Control Register and Read the process ID.
*/
.text
__after_proc_init:
M_CLASS(movw r12, #:lower16:BASEADDR_V7M_SCB)
M_CLASS(movt r12, #:upper16:BASEADDR_V7M_SCB)
#ifdef CONFIG_ARM_MPU
M_CLASS(ldr r3, [r12, 0x50])
AR_CLASS(mrc p15, 0, r3, c0, c1, 4) @ Read ID_MMFR0
and r3, r3, #(MMFR0_PMSA) @ PMSA field
teq r3, #(MMFR0_PMSAv7) @ PMSA v7
beq 1f
teq r3, #(MMFR0_PMSAv8) @ PMSA v8
/*
* Memory region attributes for PMSAv8:
*
* n = AttrIndx[2:0]
* n MAIR
* DEVICE_nGnRnE 000 00000000
* NORMAL 001 11111111
*/
ldreq r3, =PMSAv8_MAIR(0x00, PMSAv8_RGN_DEVICE_nGnRnE) | \
PMSAv8_MAIR(0xff, PMSAv8_RGN_NORMAL)
AR_CLASS(mcreq p15, 0, r3, c10, c2, 0) @ MAIR 0
M_CLASS(streq r3, [r12, #PMSAv8_MAIR0])
moveq r3, #0
AR_CLASS(mcreq p15, 0, r3, c10, c2, 1) @ MAIR 1
M_CLASS(streq r3, [r12, #PMSAv8_MAIR1])
1:
#endif
#ifdef CONFIG_CPU_CP15
/*
* CP15 system control register value returned in r0 from
* the CPU init function.
*/
#ifdef CONFIG_ARM_MPU
biceq r0, r0, #CR_BR @ Disable the 'default mem-map'
orreq r0, r0, #CR_M @ Set SCTRL.M (MPU on)
#endif
#if defined(CONFIG_ALIGNMENT_TRAP) && __LINUX_ARM_ARCH__ < 6
orr r0, r0, #CR_A
#else
bic r0, r0, #CR_A
#endif
#ifdef CONFIG_CPU_DCACHE_DISABLE
bic r0, r0, #CR_C
#endif
#ifdef CONFIG_CPU_BPREDICT_DISABLE
bic r0, r0, #CR_Z
#endif
#ifdef CONFIG_CPU_ICACHE_DISABLE
bic r0, r0, #CR_I
#endif
mcr p15, 0, r0, c1, c0, 0 @ write control reg
instr_sync
#elif defined (CONFIG_CPU_V7M)
#ifdef CONFIG_ARM_MPU
ldreq r3, [r12, MPU_CTRL]
biceq r3, #MPU_CTRL_PRIVDEFENA
orreq r3, #MPU_CTRL_ENABLE
streq r3, [r12, MPU_CTRL]
isb
#endif
/* For V7M systems we want to modify the CCR similarly to the SCTLR */
#ifdef CONFIG_CPU_DCACHE_DISABLE
bic r0, r0, #V7M_SCB_CCR_DC
#endif
#ifdef CONFIG_CPU_BPREDICT_DISABLE
bic r0, r0, #V7M_SCB_CCR_BP
#endif
#ifdef CONFIG_CPU_ICACHE_DISABLE
bic r0, r0, #V7M_SCB_CCR_IC
#endif
str r0, [r12, V7M_SCB_CCR]
/* Pass exc_ret to __mmap_switched */
mov r0, r10
#endif /* CONFIG_CPU_CP15 elif CONFIG_CPU_V7M */
ret lr
ENDPROC(__after_proc_init)
.ltorg
#ifdef CONFIG_ARM_MPU
#ifndef CONFIG_CPU_V7M
/* Set which MPU region should be programmed */
.macro set_region_nr tmp, rgnr, unused
mov \tmp, \rgnr @ Use static region numbers
mcr p15, 0, \tmp, c6, c2, 0 @ Write RGNR
.endm
/* Setup a single MPU region, either D or I side (D-side for unified) */
.macro setup_region bar, acr, sr, side = PMSAv7_DATA_SIDE, unused
mcr p15, 0, \bar, c6, c1, (0 + \side) @ I/DRBAR
mcr p15, 0, \acr, c6, c1, (4 + \side) @ I/DRACR
mcr p15, 0, \sr, c6, c1, (2 + \side) @ I/DRSR
.endm
#else
.macro set_region_nr tmp, rgnr, base
mov \tmp, \rgnr
str \tmp, [\base, #PMSAv7_RNR]
.endm
.macro setup_region bar, acr, sr, unused, base
lsl \acr, \acr, #16
orr \acr, \acr, \sr
str \bar, [\base, #PMSAv7_RBAR]
str \acr, [\base, #PMSAv7_RASR]
.endm
#endif
/*
* Setup the MPU and initial MPU Regions. We create the following regions:
* Region 0: Use this for probing the MPU details, so leave disabled.
* Region 1: Background region - covers the whole of RAM as strongly ordered
* Region 2: Normal, Shared, cacheable for RAM. From PHYS_OFFSET, size from r6
* Region 3: Normal, shared, inaccessible from PL0 to protect the vectors page
*
* r6: Value to be written to DRSR (and IRSR if required) for PMSAv7_RAM_REGION
*/
__HEAD
ENTRY(__setup_mpu)
/* Probe for v7 PMSA compliance */
M_CLASS(movw r12, #:lower16:BASEADDR_V7M_SCB)
M_CLASS(movt r12, #:upper16:BASEADDR_V7M_SCB)
AR_CLASS(mrc p15, 0, r0, c0, c1, 4) @ Read ID_MMFR0
M_CLASS(ldr r0, [r12, 0x50])
and r0, r0, #(MMFR0_PMSA) @ PMSA field
teq r0, #(MMFR0_PMSAv7) @ PMSA v7
beq __setup_pmsa_v7
teq r0, #(MMFR0_PMSAv8) @ PMSA v8
beq __setup_pmsa_v8
ret lr
ENDPROC(__setup_mpu)
ENTRY(__setup_pmsa_v7)
/* Calculate the size of a region covering just the kernel */
ldr r5, =PLAT_PHYS_OFFSET @ Region start: PHYS_OFFSET
ldr r6, =(_end) @ Cover whole kernel
sub r6, r6, r5 @ Minimum size of region to map
clz r6, r6 @ Region size must be 2^N...
rsb r6, r6, #31 @ ...so round up region size
lsl r6, r6, #PMSAv7_RSR_SZ @ Put size in right field
orr r6, r6, #(1 << PMSAv7_RSR_EN) @ Set region enabled bit
/* Determine whether the D/I-side memory map is unified. We set the
* flags here and continue to use them for the rest of this function */
AR_CLASS(mrc p15, 0, r0, c0, c0, 4) @ MPUIR
M_CLASS(ldr r0, [r12, #MPU_TYPE])
ands r5, r0, #MPUIR_DREGION_SZMASK @ 0 size d region => No MPU
bxeq lr
tst r0, #MPUIR_nU @ MPUIR_nU = 0 for unified
/* Setup second region first to free up r6 */
set_region_nr r0, #PMSAv7_RAM_REGION, r12
isb
/* Full access from PL0, PL1, shared for CONFIG_SMP, cacheable */
ldr r0, =PLAT_PHYS_OFFSET @ RAM starts at PHYS_OFFSET
ldr r5,=(PMSAv7_AP_PL1RW_PL0RW | PMSAv7_RGN_NORMAL)
setup_region r0, r5, r6, PMSAv7_DATA_SIDE, r12 @ PHYS_OFFSET, shared, enabled
beq 1f @ Memory-map not unified
setup_region r0, r5, r6, PMSAv7_INSTR_SIDE, r12 @ PHYS_OFFSET, shared, enabled
1: isb
/* First/background region */
set_region_nr r0, #PMSAv7_BG_REGION, r12
isb
/* Execute Never, strongly ordered, inaccessible to PL0, rw PL1 */
mov r0, #0 @ BG region starts at 0x0
ldr r5,=(PMSAv7_ACR_XN | PMSAv7_RGN_STRONGLY_ORDERED | PMSAv7_AP_PL1RW_PL0NA)
mov r6, #PMSAv7_RSR_ALL_MEM @ 4GB region, enabled
setup_region r0, r5, r6, PMSAv7_DATA_SIDE, r12 @ 0x0, BG region, enabled
beq 2f @ Memory-map not unified
setup_region r0, r5, r6, PMSAv7_INSTR_SIDE r12 @ 0x0, BG region, enabled
2: isb
#ifdef CONFIG_XIP_KERNEL
set_region_nr r0, #PMSAv7_ROM_REGION, r12
isb
ldr r5,=(PMSAv7_AP_PL1RO_PL0NA | PMSAv7_RGN_NORMAL)
ldr r0, =CONFIG_XIP_PHYS_ADDR @ ROM start
ldr r6, =(_exiprom) @ ROM end
sub r6, r6, r0 @ Minimum size of region to map
clz r6, r6 @ Region size must be 2^N...
rsb r6, r6, #31 @ ...so round up region size
lsl r6, r6, #PMSAv7_RSR_SZ @ Put size in right field
orr r6, r6, #(1 << PMSAv7_RSR_EN) @ Set region enabled bit
setup_region r0, r5, r6, PMSAv7_DATA_SIDE, r12 @ XIP_PHYS_ADDR, shared, enabled
beq 3f @ Memory-map not unified
setup_region r0, r5, r6, PMSAv7_INSTR_SIDE, r12 @ XIP_PHYS_ADDR, shared, enabled
3: isb
#endif
ret lr
ENDPROC(__setup_pmsa_v7)
ENTRY(__setup_pmsa_v8)
mov r0, #0
AR_CLASS(mcr p15, 0, r0, c6, c2, 1) @ PRSEL
M_CLASS(str r0, [r12, #PMSAv8_RNR])
isb
#ifdef CONFIG_XIP_KERNEL
ldr r5, =CONFIG_XIP_PHYS_ADDR @ ROM start
ldr r6, =(_exiprom) @ ROM end
sub r6, r6, #1
bic r6, r6, #(PMSAv8_MINALIGN - 1)
orr r5, r5, #(PMSAv8_AP_PL1RW_PL0NA | PMSAv8_RGN_SHARED)
orr r6, r6, #(PMSAv8_LAR_IDX(PMSAv8_RGN_NORMAL) | PMSAv8_LAR_EN)
AR_CLASS(mcr p15, 0, r5, c6, c8, 0) @ PRBAR0
AR_CLASS(mcr p15, 0, r6, c6, c8, 1) @ PRLAR0
M_CLASS(str r5, [r12, #PMSAv8_RBAR_A(0)])
M_CLASS(str r6, [r12, #PMSAv8_RLAR_A(0)])
#endif
ldr r5, =KERNEL_START
ldr r6, =KERNEL_END
sub r6, r6, #1
bic r6, r6, #(PMSAv8_MINALIGN - 1)
orr r5, r5, #(PMSAv8_AP_PL1RW_PL0NA | PMSAv8_RGN_SHARED)
orr r6, r6, #(PMSAv8_LAR_IDX(PMSAv8_RGN_NORMAL) | PMSAv8_LAR_EN)
AR_CLASS(mcr p15, 0, r5, c6, c8, 4) @ PRBAR1
AR_CLASS(mcr p15, 0, r6, c6, c8, 5) @ PRLAR1
M_CLASS(str r5, [r12, #PMSAv8_RBAR_A(1)])
M_CLASS(str r6, [r12, #PMSAv8_RLAR_A(1)])
/* Setup Background: 0x0 - min(KERNEL_START, XIP_PHYS_ADDR) */
#ifdef CONFIG_XIP_KERNEL
ldr r6, =KERNEL_START
ldr r5, =CONFIG_XIP_PHYS_ADDR
cmp r6, r5
movcs r6, r5
#else
ldr r6, =KERNEL_START
#endif
cmp r6, #0
beq 1f
mov r5, #0
sub r6, r6, #1
bic r6, r6, #(PMSAv8_MINALIGN - 1)
orr r5, r5, #(PMSAv8_AP_PL1RW_PL0NA | PMSAv8_RGN_SHARED | PMSAv8_BAR_XN)
orr r6, r6, #(PMSAv8_LAR_IDX(PMSAv8_RGN_DEVICE_nGnRnE) | PMSAv8_LAR_EN)
AR_CLASS(mcr p15, 0, r5, c6, c9, 0) @ PRBAR2
AR_CLASS(mcr p15, 0, r6, c6, c9, 1) @ PRLAR2
M_CLASS(str r5, [r12, #PMSAv8_RBAR_A(2)])
M_CLASS(str r6, [r12, #PMSAv8_RLAR_A(2)])
1:
/* Setup Background: max(KERNEL_END, _exiprom) - 0xffffffff */
#ifdef CONFIG_XIP_KERNEL
ldr r5, =KERNEL_END
ldr r6, =(_exiprom)
cmp r5, r6
movcc r5, r6
#else
ldr r5, =KERNEL_END
#endif
mov r6, #0xffffffff
bic r6, r6, #(PMSAv8_MINALIGN - 1)
orr r5, r5, #(PMSAv8_AP_PL1RW_PL0NA | PMSAv8_RGN_SHARED | PMSAv8_BAR_XN)
orr r6, r6, #(PMSAv8_LAR_IDX(PMSAv8_RGN_DEVICE_nGnRnE) | PMSAv8_LAR_EN)
AR_CLASS(mcr p15, 0, r5, c6, c9, 4) @ PRBAR3
AR_CLASS(mcr p15, 0, r6, c6, c9, 5) @ PRLAR3
M_CLASS(str r5, [r12, #PMSAv8_RBAR_A(3)])
M_CLASS(str r6, [r12, #PMSAv8_RLAR_A(3)])
#ifdef CONFIG_XIP_KERNEL
/* Setup Background: min(_exiprom, KERNEL_END) - max(KERNEL_START, XIP_PHYS_ADDR) */
ldr r5, =(_exiprom)
ldr r6, =KERNEL_END
cmp r5, r6
movcs r5, r6
ldr r6, =KERNEL_START
ldr r0, =CONFIG_XIP_PHYS_ADDR
cmp r6, r0
movcc r6, r0
sub r6, r6, #1
bic r6, r6, #(PMSAv8_MINALIGN - 1)
orr r5, r5, #(PMSAv8_AP_PL1RW_PL0NA | PMSAv8_RGN_SHARED | PMSAv8_BAR_XN)
orr r6, r6, #(PMSAv8_LAR_IDX(PMSAv8_RGN_DEVICE_nGnRnE) | PMSAv8_LAR_EN)
#ifdef CONFIG_CPU_V7M
/* There is no alias for n == 4 */
mov r0, #4
str r0, [r12, #PMSAv8_RNR] @ PRSEL
isb
str r5, [r12, #PMSAv8_RBAR_A(0)]
str r6, [r12, #PMSAv8_RLAR_A(0)]
#else
mcr p15, 0, r5, c6, c10, 0 @ PRBAR4
mcr p15, 0, r6, c6, c10, 1 @ PRLAR4
#endif
#endif
ret lr
ENDPROC(__setup_pmsa_v8)
#ifdef CONFIG_SMP
/*
* r6: pointer at mpu_rgn_info
*/
.text
ENTRY(__secondary_setup_mpu)
/* Use MPU region info supplied by __cpu_up */
ldr r6, [r7] @ get secondary_data.mpu_rgn_info
/* Probe for v7 PMSA compliance */
mrc p15, 0, r0, c0, c1, 4 @ Read ID_MMFR0
and r0, r0, #(MMFR0_PMSA) @ PMSA field
teq r0, #(MMFR0_PMSAv7) @ PMSA v7
beq __secondary_setup_pmsa_v7
teq r0, #(MMFR0_PMSAv8) @ PMSA v8
beq __secondary_setup_pmsa_v8
b __error_p
ENDPROC(__secondary_setup_mpu)
/*
* r6: pointer at mpu_rgn_info
*/
ENTRY(__secondary_setup_pmsa_v7)
/* Determine whether the D/I-side memory map is unified. We set the
* flags here and continue to use them for the rest of this function */
mrc p15, 0, r0, c0, c0, 4 @ MPUIR
ands r5, r0, #MPUIR_DREGION_SZMASK @ 0 size d region => No MPU
beq __error_p
ldr r4, [r6, #MPU_RNG_INFO_USED]
mov r5, #MPU_RNG_SIZE
add r3, r6, #MPU_RNG_INFO_RNGS
mla r3, r4, r5, r3
1:
tst r0, #MPUIR_nU @ MPUIR_nU = 0 for unified
sub r3, r3, #MPU_RNG_SIZE
sub r4, r4, #1
set_region_nr r0, r4
isb
ldr r0, [r3, #MPU_RGN_DRBAR]
ldr r6, [r3, #MPU_RGN_DRSR]
ldr r5, [r3, #MPU_RGN_DRACR]
setup_region r0, r5, r6, PMSAv7_DATA_SIDE
beq 2f
setup_region r0, r5, r6, PMSAv7_INSTR_SIDE
2: isb
mrc p15, 0, r0, c0, c0, 4 @ Reevaluate the MPUIR
cmp r4, #0
bgt 1b
ret lr
ENDPROC(__secondary_setup_pmsa_v7)
ENTRY(__secondary_setup_pmsa_v8)
ldr r4, [r6, #MPU_RNG_INFO_USED]
#ifndef CONFIG_XIP_KERNEL
add r4, r4, #1
#endif
mov r5, #MPU_RNG_SIZE
add r3, r6, #MPU_RNG_INFO_RNGS
mla r3, r4, r5, r3
1:
sub r3, r3, #MPU_RNG_SIZE
sub r4, r4, #1
mcr p15, 0, r4, c6, c2, 1 @ PRSEL
isb
ldr r5, [r3, #MPU_RGN_PRBAR]
ldr r6, [r3, #MPU_RGN_PRLAR]
mcr p15, 0, r5, c6, c3, 0 @ PRBAR
mcr p15, 0, r6, c6, c3, 1 @ PRLAR
cmp r4, #0
bgt 1b
ret lr
ENDPROC(__secondary_setup_pmsa_v8)
#endif /* CONFIG_SMP */
#endif /* CONFIG_ARM_MPU */
#include "head-common.S"
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