diff options
| -rw-r--r-- | arch/arm/include/asm/mpu.h | 3 | ||||
| -rw-r--r-- | arch/arm/kernel/head-nommu.S | 87 |
2 files changed, 90 insertions, 0 deletions
diff --git a/arch/arm/include/asm/mpu.h b/arch/arm/include/asm/mpu.h index bd48c0cb544e..001483465aa4 100644 --- a/arch/arm/include/asm/mpu.h +++ b/arch/arm/include/asm/mpu.h @@ -50,6 +50,9 @@ /* Maximum number of regions Linux is interested in */ #define MPU_MAX_REGIONS 16 +#define MPU_DATA_SIDE 0 +#define MPU_INSTR_SIDE 1 + #ifndef __ASSEMBLY__ struct mpu_rgn { diff --git a/arch/arm/kernel/head-nommu.S b/arch/arm/kernel/head-nommu.S index 06ba9c8e62be..659912c49571 100644 --- a/arch/arm/kernel/head-nommu.S +++ b/arch/arm/kernel/head-nommu.S @@ -17,9 +17,11 @@ #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> /* * Kernel startup entry point. @@ -63,6 +65,17 @@ ENTRY(stext) movs r10, r5 @ invalid processor (r5=0)? beq __error_p @ yes, error 'p' +#ifdef CONFIG_ARM_MPU + /* Calculate the size of a region covering just the kernel */ + ldr r5, =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, #MPU_RSR_SZ @ Put size in right field + orr r6, r6, #(1 << MPU_RSR_EN) @ Set region enabled bit + bl __setup_mpu +#endif ldr r13, =__mmap_switched @ address to jump to after @ initialising sctlr adr lr, BSYM(1f) @ return (PIC) address @@ -147,4 +160,78 @@ __after_proc_init: ENDPROC(__after_proc_init) .ltorg +#ifdef CONFIG_ARM_MPU + + +/* Set which MPU region should be programmed */ +.macro set_region_nr tmp, rgnr + 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 = MPU_DATA_SIDE + 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 + +/* + * 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 + * + * r6: Value to be written to DRSR (and IRSR if required) for MPU_RAM_REGION +*/ + +ENTRY(__setup_mpu) + + /* 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 + bne __error_p @ Fail: ARM_MPU on NOT v7 PMSA + + /* 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 @ Fail: ARM_MPU and no MPU + tst r0, #MPUIR_nU @ MPUIR_nU = 0 for unified + + /* Setup second region first to free up r6 */ + set_region_nr r0, #MPU_RAM_REGION + isb + /* Full access from PL0, PL1, shared for CONFIG_SMP, cacheable */ + ldr r0, =PHYS_OFFSET @ RAM starts at PHYS_OFFSET + ldr r5,=(MPU_AP_PL1RW_PL0RW | MPU_RGN_NORMAL) + + setup_region r0, r5, r6, MPU_DATA_SIDE @ PHYS_OFFSET, shared, enabled + beq 1f @ Memory-map not unified + setup_region r0, r5, r6, MPU_INSTR_SIDE @ PHYS_OFFSET, shared, enabled +1: isb + + /* First/background region */ + set_region_nr r0, #MPU_BG_REGION + isb + /* Execute Never, strongly ordered, inaccessible to PL0, rw PL1 */ + mov r0, #0 @ BG region starts at 0x0 + ldr r5,=(MPU_ACR_XN | MPU_RGN_STRONGLY_ORDERED | MPU_AP_PL1RW_PL0NA) + mov r6, #MPU_RSR_ALL_MEM @ 4GB region, enabled + + setup_region r0, r5, r6, MPU_DATA_SIDE @ 0x0, BG region, enabled + beq 2f @ Memory-map not unified + setup_region r0, r5, r6, MPU_INSTR_SIDE @ 0x0, BG region, enabled +2: isb + + /* Enable the MPU */ + mrc p15, 0, r0, c1, c0, 0 @ Read SCTLR + bic r0, r0, #CR_BR @ Disable the 'default mem-map' + orr r0, r0, #CR_M @ Set SCTRL.M (MPU on) + mcr p15, 0, r0, c1, c0, 0 @ Enable MPU + isb + mov pc,lr +ENDPROC(__setup_mpu) +#endif #include "head-common.S" |