[PATCH v2 6/8] ARM: V7M: Add support for MPU to M-class
Vladimir Murzin
vladimir.murzin at arm.com
Fri Jul 21 06:12:34 PDT 2017
This patch makes it possible to use MPU with v7M cores.
Tested-by: Szemző András <sza at esh.hu>
Signed-off-by: Vladimir Murzin <vladimir.murzin at arm.com>
---
arch/arm/Kconfig-nommu | 4 +--
arch/arm/include/asm/cputype.h | 10 ++++++++
arch/arm/include/asm/v7m.h | 10 ++++++++
arch/arm/kernel/head-nommu.S | 56 ++++++++++++++++++++++++++++++------------
arch/arm/mm/pmsa-v7.c | 53 +++++++++++++++++++++++++++++++++++++--
5 files changed, 113 insertions(+), 20 deletions(-)
diff --git a/arch/arm/Kconfig-nommu b/arch/arm/Kconfig-nommu
index 6d18395..930e000 100644
--- a/arch/arm/Kconfig-nommu
+++ b/arch/arm/Kconfig-nommu
@@ -52,8 +52,8 @@ config REMAP_VECTORS_TO_RAM
config ARM_MPU
bool 'Use the ARM v7 PMSA Compliant MPU'
- depends on !XIP_KERNEL && CPU_V7
- default y
+ depends on !XIP_KERNEL && (CPU_V7 || CPU_V7M)
+ default y if CPU_V7
help
Some ARM systems without an MMU have instead a Memory Protection
Unit (MPU) that defines the type and permissions for regions of
diff --git a/arch/arm/include/asm/cputype.h b/arch/arm/include/asm/cputype.h
index b62eaeb..abaac5e 100644
--- a/arch/arm/include/asm/cputype.h
+++ b/arch/arm/include/asm/cputype.h
@@ -173,6 +173,11 @@ static inline unsigned int __attribute_const__ read_cpuid_cachetype(void)
return read_cpuid(CPUID_CACHETYPE);
}
+static inline unsigned int __attribute_const__ read_cpuid_mputype(void)
+{
+ return read_cpuid(CPUID_MPUIR);
+}
+
#elif defined(CONFIG_CPU_V7M)
static inline unsigned int __attribute_const__ read_cpuid_id(void)
@@ -185,6 +190,11 @@ static inline unsigned int __attribute_const__ read_cpuid_cachetype(void)
return readl(BASEADDR_V7M_SCB + V7M_SCB_CTR);
}
+static inline unsigned int __attribute_const__ read_cpuid_mputype(void)
+{
+ return readl(BASEADDR_V7M_SCB + MPU_TYPE);
+}
+
#else /* ifdef CONFIG_CPU_CP15 / elif defined(CONFIG_CPU_V7M) */
static inline unsigned int __attribute_const__ read_cpuid_id(void)
diff --git a/arch/arm/include/asm/v7m.h b/arch/arm/include/asm/v7m.h
index 1fd775c..5de776c 100644
--- a/arch/arm/include/asm/v7m.h
+++ b/arch/arm/include/asm/v7m.h
@@ -57,6 +57,16 @@
#define V7M_SCB_CCSIDR 0x80 /* Cache size ID register */
#define V7M_SCB_CSSELR 0x84 /* Cache size selection register */
+/* Memory-mapped MPU registers for M-class */
+#define MPU_TYPE 0x90
+#define MPU_CTRL 0x94
+#define MPU_CTRL_ENABLE 1
+#define MPU_CTRL_PRIVDEFENA (1 << 2)
+
+#define MPU_RNR 0x98
+#define MPU_RBAR 0x9c
+#define MPU_RASR 0xa0
+
/* Cache opeartions */
#define V7M_SCB_ICIALLU 0x250 /* I-cache invalidate all to PoU */
#define V7M_SCB_ICIMVAU 0x258 /* I-cache invalidate by MVA to PoU */
diff --git a/arch/arm/kernel/head-nommu.S b/arch/arm/kernel/head-nommu.S
index 5f90a5f..0d64b8b 100644
--- a/arch/arm/kernel/head-nommu.S
+++ b/arch/arm/kernel/head-nommu.S
@@ -176,19 +176,33 @@ ENDPROC(__after_proc_init)
#ifdef CONFIG_ARM_MPU
+#ifndef CONFIG_CPU_V7M
/* Set which MPU region should be programmed */
-.macro set_region_nr tmp, rgnr
+.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 = MPU_DATA_SIDE
+.macro setup_region bar, acr, sr, side = MPU_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, #MPU_RNR]
+.endm
+
+.macro setup_region bar, acr, sr, unused, base
+ lsl \acr, \acr, #16
+ orr \acr, \acr, \sr
+ str \bar, [\base, #MPU_RBAR]
+ str \acr, [\base, #MPU_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.
@@ -202,48 +216,58 @@ ENDPROC(__after_proc_init)
ENTRY(__setup_mpu)
/* Probe for v7 PMSA compliance */
- mrc p15, 0, r0, c0, c1, 4 @ Read ID_MMFR0
+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
bxne lr
/* 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
+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, #MPU_RAM_REGION
+ set_region_nr r0, #MPU_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,=(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
+ setup_region r0, r5, r6, MPU_DATA_SIDE, r12 @ PHYS_OFFSET, shared, enabled
+ beq 1f @ Memory-map not unified
+ setup_region r0, r5, r6, MPU_INSTR_SIDE, r12 @ PHYS_OFFSET, shared, enabled
1: isb
/* First/background region */
- set_region_nr r0, #MPU_BG_REGION
+ set_region_nr r0, #MPU_BG_REGION, r12
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
+ setup_region r0, r5, r6, MPU_DATA_SIDE, r12 @ 0x0, BG region, enabled
+ beq 2f @ Memory-map not unified
+ setup_region r0, r5, r6, MPU_INSTR_SIDE r12 @ 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
+AR_CLASS(mrc p15, 0, r0, c1, c0, 0) @ Read SCTLR
+AR_CLASS(bic r0, r0, #CR_BR) @ Disable the 'default mem-map'
+AR_CLASS(orr r0, r0, #CR_M) @ Set SCTRL.M (MPU on)
+AR_CLASS(mcr p15, 0, r0, c1, c0, 0) @ Enable MPU
+
+M_CLASS(ldr r0, [r12, #MPU_CTRL])
+M_CLASS(bic r0, #MPU_CTRL_PRIVDEFENA)
+M_CLASS(orr r0, #MPU_CTRL_ENABLE)
+M_CLASS(str r0, [r12, #MPU_CTRL])
isb
ret lr
diff --git a/arch/arm/mm/pmsa-v7.c b/arch/arm/mm/pmsa-v7.c
index 029d204..72f1a9f 100644
--- a/arch/arm/mm/pmsa-v7.c
+++ b/arch/arm/mm/pmsa-v7.c
@@ -15,6 +15,8 @@
static unsigned int __initdata mpu_min_region_order;
static unsigned int __initdata mpu_max_regions;
+#ifndef CONFIG_CPU_V7M
+
#define DRBAR __ACCESS_CP15(c6, 0, c1, 0)
#define IRBAR __ACCESS_CP15(c6, 0, c1, 1)
#define DRSR __ACCESS_CP15(c6, 0, c1, 2)
@@ -78,6 +80,51 @@ static inline u32 irbar_read(void)
return read_sysreg(IRBAR);
}
+#else
+
+static inline void rgnr_write(u32 v)
+{
+ writel_relaxed(v, BASEADDR_V7M_SCB + MPU_RNR);
+}
+
+/* Data-side / unified region attributes */
+
+/* Region access control register */
+static inline void dracr_write(u32 v)
+{
+ u32 rsr = readl_relaxed(BASEADDR_V7M_SCB + MPU_RASR) & GENMASK(15, 0);
+
+ writel_relaxed((v << 16) | rsr, BASEADDR_V7M_SCB + MPU_RASR);
+}
+
+/* Region size register */
+static inline void drsr_write(u32 v)
+{
+ u32 racr = readl_relaxed(BASEADDR_V7M_SCB + MPU_RASR) & GENMASK(31, 16);
+
+ writel_relaxed(v | racr, BASEADDR_V7M_SCB + MPU_RASR);
+}
+
+/* Region base address register */
+static inline void drbar_write(u32 v)
+{
+ writel_relaxed(v, BASEADDR_V7M_SCB + MPU_RBAR);
+}
+
+static inline u32 drbar_read(void)
+{
+ return readl_relaxed(BASEADDR_V7M_SCB + MPU_RBAR);
+}
+
+/* ARMv7-M only supports a unified MPU, so I-side operations are nop */
+
+static inline void iracr_write(u32 v) {}
+static inline void irsr_write(u32 v) {}
+static inline void irbar_write(u32 v) {}
+static inline unsigned long irbar_read(void) {return 0;}
+
+#endif
+
static int __init mpu_present(void)
{
return ((read_cpuid_ext(CPUID_EXT_MMFR0) & MMFR0_PMSA) == MMFR0_PMSAv7);
@@ -166,7 +213,7 @@ static int __init __mpu_max_regions(void)
*/
u32 dregions, iregions, mpuir;
- mpuir = read_cpuid(CPUID_MPUIR);
+ mpuir = read_cpuid_mputype();
dregions = iregions = (mpuir & MPUIR_DREGION_SZMASK) >> MPUIR_DREGION;
@@ -181,7 +228,7 @@ static int __init __mpu_max_regions(void)
static int __init mpu_iside_independent(void)
{
/* MPUIR.nU specifies whether there is *not* a unified memory map */
- return read_cpuid(CPUID_MPUIR) & MPUIR_nU;
+ return read_cpuid_mputype() & MPUIR_nU;
}
static int __init __mpu_min_region_order(void)
@@ -284,9 +331,11 @@ void __init mpu_setup(void)
MPU_AP_PL1RW_PL0RW | MPU_RGN_NORMAL);
/* Vectors */
+#ifndef CONFIG_CPU_V7M
err |= mpu_setup_region(region++, vectors_base,
ilog2(2 * PAGE_SIZE),
MPU_AP_PL1RW_PL0NA | MPU_RGN_NORMAL);
+#endif
if (err) {
panic("MPU region initialization failure! %d", err);
} else {
--
2.0.0
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