[PATCHv3 08/11] arm64: Check for selected granule support
From: Suzuki K. Poulose
Date: Wed Oct 14 2015 - 07:22:52 EST
Ensure that the selected page size is supported by the
CPU(s).
Cc: Mark Rutland <mark.rutland@xxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Will Deacon <will.deacon@xxxxxxx>
Signed-off-by: Suzuki K. Poulose <suzuki.poulose@xxxxxxx>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
Tested-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
---
arch/arm64/include/asm/sysreg.h | 12 ++++++++++++
arch/arm64/kernel/head.S | 28 ++++++++++++++++++++++++++--
2 files changed, 38 insertions(+), 2 deletions(-)
diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysreg.h
index a7f3d4b..1f07cc5 100644
--- a/arch/arm64/include/asm/sysreg.h
+++ b/arch/arm64/include/asm/sysreg.h
@@ -44,6 +44,18 @@
#define SET_PSTATE_PAN(x) __inst_arm(0xd5000000 | REG_PSTATE_PAN_IMM |\
(!!x)<<8 | 0x1f)
+
+#define ID_AA64MMFR0_TGRAN4_SHIFT 28
+#define ID_AA64MMFR0_TGRAN64_SHIFT 24
+#define ID_AA64MMFR0_TGRAN16_SHIFT 20
+
+#define ID_AA64MMFR0_TGRAN4_NI 0xf
+#define ID_AA64MMFR0_TGRAN4_ON 0x0
+#define ID_AA64MMFR0_TGRAN64_NI 0xf
+#define ID_AA64MMFR0_TGRAN64_ON 0x0
+#define ID_AA64MMFR0_TGRAN16_NI 0x0
+#define ID_AA64MMFR0_TGRAN16_ON 0x1
+
#ifdef __ASSEMBLY__
.irp num,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30
diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S
index 7ace955..b6aa9e0 100644
--- a/arch/arm64/kernel/head.S
+++ b/arch/arm64/kernel/head.S
@@ -31,10 +31,11 @@
#include <asm/cputype.h>
#include <asm/kernel-pgtable.h>
#include <asm/memory.h>
-#include <asm/thread_info.h>
#include <asm/pgtable-hwdef.h>
#include <asm/pgtable.h>
#include <asm/page.h>
+#include <asm/sysreg.h>
+#include <asm/thread_info.h>
#include <asm/virt.h>
#define __PHYS_OFFSET (KERNEL_START - TEXT_OFFSET)
@@ -613,10 +614,28 @@ ENDPROC(__secondary_switched)
* x0 = SCTLR_EL1 value for turning on the MMU.
* x27 = *virtual* address to jump to upon completion
*
- * other registers depend on the function called upon completion
+ * Other registers depend on the function called upon completion.
+ *
+ * Checks if the selected granule size is supported by the CPU.
+ * If it doesn't park the CPU
*/
+#if defined(CONFIG_ARM64_64K_PAGES)
+
+#define id_aa64mmfr0_tgran_shift ID_AA64MMFR0_TGRAN64_SHIFT
+#define id_aa64mmfr0_tgran_on ID_AA64MMFR0_TGRAN64_ON
+
+#else
+
+#define id_aa64mmfr0_tgran_shift ID_AA64MMFR0_TGRAN4_SHIFT
+#define id_aa64mmfr0_tgran_on ID_AA64MMFR0_TGRAN4_ON
+
+#endif
.section ".idmap.text", "ax"
__enable_mmu:
+ mrs x1, ID_AA64MMFR0_EL1
+ ubfx x2, x1, #id_aa64mmfr0_tgran_shift, 4
+ cmp x2, #id_aa64mmfr0_tgran_on
+ b.ne __no_granule_support
ldr x5, =vectors
msr vbar_el1, x5
msr ttbr0_el1, x25 // load TTBR0
@@ -634,3 +653,8 @@ __enable_mmu:
isb
br x27
ENDPROC(__enable_mmu)
+
+__no_granule_support:
+ wfe
+ b __no_granule_support
+ENDPROC(__no_granule_support)
--
1.7.9.5
--
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