diff options
Diffstat (limited to 'arch/arm/kernel/head-nommu.S')
| -rw-r--r-- | arch/arm/kernel/head-nommu.S | 537 |
1 files changed, 537 insertions, 0 deletions
diff --git a/arch/arm/kernel/head-nommu.S b/arch/arm/kernel/head-nommu.S new file mode 100644 index 000000000..950bef833 --- /dev/null +++ b/arch/arm/kernel/head-nommu.S @@ -0,0 +1,537 @@ +/* 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/memory.h> +#include <asm/cp15.h> +#include <asm/thread_info.h> +#include <asm/v7m.h> +#include <asm/mpu.h> +#include <asm/page.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" |